By the way, Husqvarna offers several Rider versions, same hydro unit, with engine hp as high as 16hp, so this won't be THAT overpowered, and will surely get as good fuel consumption as the 28ci flathead [petrol is 2.25/lit =aprox. $9/gal] with a bit more power.. I've been wanting to stick with the B&S as it'll be a plug and play [elec.] and the older single cylinder Vanguard as it'll fit right in [V-twin will hit battery box].
I've thought about this a bit, unless anyone can figure something else to factor in.
Thanks, John

I've found SOME info, such as at:
http://www.smallenginesurplus.com/briggs-stratton-short-block-part-number-697762-p-3536.htm
That says that this short block is the same for the 28pxxx and 28qxxx which I'm fairly sure are Vanguards.
So, I'm thinking that the 312777 is a Vanguard, just looking for some independent confirmation.
Thanks, John

Download the owners manual from Briggs-
http://www.briggsandstratton.com/us/en/support/manuals

It shows Intek on one of the cover models.

I'm not going to claim I know all the Briggs Models, but it seems to me the 28 & 31 series are NOT Vanguards.

This post was edited by bill_kapaun on Tue, Jan 21, 14 at 9:06

Bill would be correct. The shrouding looked more Vangard than Intek, but yes it has Intek guts. The thing with these is they were good engines and it could be a good swap. That is if the exhaust would work from the Toro and is in good shape. Though Toro did say they put Vangards on some XLs back in the day, I just don't recall which ones. 71197 99- is likely the Toro model if you wish to research further.

28Q777 would be the largest single cylinder Vanguard made, and I'm inclined to think that the 28Q777 is nothing but a sheep in wolf's clothing (not a real old school Vanguard at all).
312777 IS NOT in the Vanguard family.
B&S uses a proprietary engine identification strategy that reveals SOME information at a glance, but to find out obscure info like the Briggs marketplace name (e.g. Vanguard, Intek, etc.) bestowed on a particular engine, you may have to e-mail Briggs & Stratton with your question.
Using the B&S engine ID strategy, basic info of 312777 in the "left to right" order of characters comes out as:
31....engine displacement in cubic inches
2....basic engine design # 2
7.....vertical crankshaft
7.....plain bearing with pressure lubrication
7.....electric starter @ 12 or 24 volts DC, with alternator

If the single cylinder engine in question were a horizontal crankshaft engine, it would be very obvious whether it was a Vanguard or not. The horizontal Vanguard's cylinder is canted at an angle (related to the flat engine mounting plane of the sump) and the overall profile of the engine when viewed from the crankshaft end looks like a Vee twin engine with one cylinder sliced away, and essentially, that is exactly how Briggs derived a single cylinder Vanguard engine out of the original Vanguard Vee Twin design.
The 1/2 of a Vee Twin appearance is not so obvious when looking at a vertical crankshaft Vanguard single because the engine mounting plane is moved to the crankshaft PTO end sump case.
I also do not believe that all the engines Briggs has decided to label as "Vanguards" in later years are actually "genuine" Vanguards in regard to how the original Vanguard family was designed and manufactured.
After all, when you get down to the root of the matter, the name "VANGUARD" is really nothing more than a marketing ploy, and Briggs owns the name as applied to OPE engines.
And because the original Vanguards achieved almost legendary status for performance and durability, what better way to hype up an engine than to stick a Vanguard decal on it?
If Briggs decides to put a Vanguard decal on engines that do not fit the original design parameters of the Vanguard family, they can legally do that because the name Vanguard is owned by Briggs and does not represent any type of specification standard that distinguishes those engines from the other marketing names that Briggs utilizes.
Your best bet on this is going to be an e-mail to Briggs & Stratton and ask them if the Vanguard title was ever given to the 312777 you are interested in.

This post was edited by mownie on Tue, Jan 21, 14 at 12:26

I assume you are in OZ.
That :MIGHT" result in different nomenclature for engines than in the states.

Not Oz, NZ, the other down under.
When I looked at IPLs, the parts for this engine were consistent with the 28P, 28Q engine family. The 28P, Q, as far as I can tell, are real Vanguards [older single cylinder, pre v-twin].
I'm thinking that Toro had asked B&S for an upspeced version of the 28ci single. The bore is the same and uses the same piston as the 28P,Q. The IPL for the 312xxx is the same as the PQ Vanguards, it is just a stroked PQ.
The engine shrouding looks identical to the PQ engines. So, if you needed a crank for this, you'd end up with a 28ci, as I don't think the 31ci [longer stroke] crank or con rod is available.
All of the websites that have listings for these, mention them as an adjunct [same as or in addition to] to the PQ engine.
I'm thinking that the 312xxx is a stroked PQ, being 31ci, is bigger [not like the 14-16 hp rating coming from the same displacement engine].
I'll look some more and see if I can come up with any more info, I know that this is a "brand specific" engine [branded for Toro] and therefore is NOT that common. So, some diligence and research...
I'd have to say that this is one of the more informed and friendly forums on these subjects, yes, that's a compliment.
Thanks to all that have responded, you've been a great help. John

There's a lot of "28" and more "31" series engines.
I've got IPL's for 18 of the first and 26 of the 2nd.
I'm probably missing a few.

It'd be nice if the IPL's would state if Vanguard, Intek etc.
Probably more info than what Briggs wants to let out.

I've seen spec's on the 18 & 20 HP Vanguards. They were identical, except the 20 HP had a 2 barrel carb & related "intake system".
The 18 actually had more peak torque by a tiny amount.

I was at a Toro dealer at the time . I do remember the "upgraded" engines that added a oil filter w/ the pressure lube label. I don't recall more details on that and Partsmart isn't cooperating at the moment. In looking at Partstree, they show a variety of sumps available- some w/o filtration and the option of plastic ring gears. Seems Intekish. Would there be a reason to market a full pressure lube w/o a filter? Or weren't all Vangaurds FPL?
Why the distaste for the Intek? It sounds like you are repowering a basic lawntractor. Something special in your project you'd like to share?

"Something special in your project you'd like to share? "

Nothing special as far as the project is concerned. I figured that if I was going to go through the exercise of changing out the engine, OHV for flathead, that I was going to look for a premium engine. I'm sure that the Intek would be a step up [performance and fuel consumption wise], but I was not wanting to use any old consumer variety engine.
I'm in no particular hurry, so I was going to narrow down the field of candidates to be on the look out for.
I've been trying to identify tractor brands that use the up-speced engines, John Deere, Massey-Ferguson, Viking [Stihl]... I've seen the 28P and the 28Q engines in these [14-16hp]. When I saw these Toro 17-44 HXLs, and did some research, they seemed like likely candidates. There are two currently being advertised on an online auction site [Trade Me] and the listings are;
http://www.trademe.co.nz/Browse/Listing.aspx?id=687732348 and
http://www.trademe.co.nz/Browse/Listing.aspx?id=688013152.
The first one has a picture of the engine with the tapered down edge on the blower housing with the three ribs pressed in. The second one [one that I'm bidding on] has given the engine #s as 312777-0128-e1, 990506ze.
I've been trying to ID this as a Vanguard [premium engine] so as to be assured.

I'm not planning to do any heavy duty work with this, but why not get the best when donor engines are probably all about the same price, regardless of model. I've seen Tecumseh engines going for 3-400 bucks, and B&S flatheads for as much as Kohler Commands. So, if I'm looking for a particular make, model...
I think that because the "Toro 17hp power plus" is not branded as a "Vanguard", might just be the wrinkle in the market for me to procure a good engine for a good price.
I'd like to build the BEST quality that I can afford, which precludes new.
I bought the Rider 13 for $100 with a rusted out deck, and fabricated a new deck [that works great], so I've got less than $500 into this machine, and can't/don't want to afford $1,500 for an engine, so a good, used from a donor machine is what I've got to work with.
Thanks, John

So, what was Briggs and Stratton's response to your e-mail asking them if this engine in question can rightly wear a Vanguard decal?

So, what was Briggs and Stratton's response to your e-mail asking them if this engine in question can rightly wear a Vanguard decal?
I've not asked B&S specifically, they've been slow and don't really answer my specific question.
The IPL for the 312777-0128-e1 #s that I put into their manual search produced the results that I mentioned above.
The T.E. Warehouse lists the 28qxxx and the 312xxx on the same page as similar, just one is 16hp, the other is 17hp.
http://www.tulsaenginewarehouse.com/catalog/briggs/bsvert/28q700.html
I know that there is no pic of both engines, but I'd recon that they wouldn't put a picture of a Vanguard [labelled] and list these engines' descriptions as being the same if they weren't. Could be a mistake?
The single cylinder is actually the older variant of the Vanguard line, the v-twin is the newer/current version IIRC. The code being 990506ze fits in with the vintage of my machine, so assuming that the hours are similar, that'll be equal as well.
My plan is to swap out the Vanguard for the flathead, then sell the flathead for near what the price for the Vanguard was, so it'll be close to a break even proposition, with my machine ending up on the better end of the deal.
Thanks, John

Saw this:
http://www.advancedmower.com/toro/toro_xl_series.htm
Shows [in the last column] that the 17hp is a vanguard. Hmmm

Saw this:
http://www.advancedmower.com/toro/toro_xl_series.htm
Shows [in the last column] that the 17hp is a vanguard. Hmmm
I've seen some ads for 17-44hxl that DO have the Intek [engine shroud]
that sure looks different than the Vanguard. I think that these engines are able to be visually identified.

Well, you may have gotten onto something with the advertisement showing it listed as Vanguard.
But it still smells as if Briggs is guilty of hiding a product behind a well known, and presumed "premium tier" decal to promote consumer acceptance.
This practice is more widespread than the average consumer is aware of......and it is done across markets of all type products.
I don't know where or when the practice of "renaming" first began, but I have personal experience where a major manufacturer used the renaming scheme to attempt salvaging a product that had gained notoriety due to problems in service and high maintenance costs.
Of course this narrative is all anecdotal and the story was related to me by a field service representative a few years after the product was removed entirely from the options list.
I worked for a company known then as IHC. The company manufactured an engine sold as the "DV550" (and a smaller DV462) in the mid '60s. The breakdown on that was D=diesel, V= V-8 configuration, 550= 550 cubic inch displacement. A turbocharged version was available as the DVT 550.
The engines were based on the popular IHC V-461 and V-549 large V8 gas burner engines.
My experience with the engine was in medium duty highway trucks, but I was told that the engine was used in some agriculture tractors and construction equipment made by other IHC divisions.
Anyhow, the DV550 (and DVT550) soon became well known as a "less than desirable" power plant in trucks and its sales figures sagged a few years after it was introduced.
To give the ailing sales of the DV550 an image booster shot in the arm, the marketing engineers renamed the engines as the D-xxx (Diesel, xxx horsepower) available in 150, 170, and 190 HP versions. Sales subsequently rose a bit at first, but it soon became apparent that the D-xxx was just a renamed DV550 and sales then became tepid.
A few years later, the renaming took place once again and the infamous DV550 was marketed as the "9 liter", and sales inched back up a bit only to fall quickly as it was recognized as just another pseudonym for the same old product.
Thankfully, and much to the credit of IHC engine designers, IHC developed the inline 6 cylinder DT466 engine in the early '70s and finally had a product that would endure (and endear buyers). The DT 466 engine family lives on and is still being built and sold today.
I know this ran off the path and into the tall weeds but I just wanted to relate something from my own past where I first learned of how companies might employ marketing and sales engineers to rescue or promote products by associating them with well known and trusted names.........or changing names to DIS-ASSOCIATE a product from its infamously well known predecessors.

This post was edited by mownie on Sun, Jan 26, 14 at 12:59

That table you showed joggled something in my little pea brain. Toro did say that the later 17HXLs had a Vangaurd . I remember that was to build on a price point as the larger XL wasn't a big mover. The 38"s sold many times over the others. I don't consider my self a Vanguard expert, but a couple of differences come to mind. The more obvious is that the Inteks used a compression release on the intake and the Vanguards on the exhaust. In which case the aluminum push rod was used on the respective valve that the compression release was used on. So, the engine you described then should spec the aluminum push rod in the exhaust spot- but it does not. Same as the Intek with the aluminum rod in the intake spot. Don't Vanguards have a full pressure lube to the top rather than the oil circulating through the sump, filter? The sump is used on 287,28N, 28P, 28Q,28S, 28W, 310, 311,312, 313 . The head, connecting rod, cam etc. was used on those and a plethora more. I know the majority of these are common Intek mills. Could a Vanguard have possibly have a plastic ring gear? It shows as possible in the specs. Your engine could very well have the steel gear though. The shroud was used on 28P. 28Q & 312 series only. Does this fit mownie's theory that this could be a sheep in wolf's clothing? Loosely interpreted of course....
I'm of course not ditzing the Inteks as in my mind they are good little engines. If you want a Vangaurd for whatever reason, then you should have one. Hopefully, if you do grab onto this one- it was properly maintained and is really built to your desired specs.

My original objective was to replace the flathead engine as I've had experience with flathead vs ohv in similar size [apple to apple]. I've used ohv on a pressure washer [flathead B&S vs ohv Honda] and a walk behind mower [flathead B&S vs ohv B&S]. In both cases, the ohv was smaller [displacement], had more power, was quieter, and used way less fuel [more efficient].
My next objective was to find one of the "best" ohv engines to look for. I was trying to avoid a "Courage" blunder. In doing my research, the Kohler Command, Honda GXV, B&S Vanguard and the Kawasaki FS were identified as being the premium models. Each brand has a "comsumer" version, Kohler has the courage, Honda has the GCV, B&S has a myriad of lesser models [quite confusing] and Kawasaki has the FH. Now my search has been narrowed to look for ONLY these models, avoiding the consumer versions.
My next objective was to locate an inexpensive way to obtain an engine. This is most likely going to be purchasing a "donor" machine with a fault that brings down the used price of this machine, rusted/busted deck, bad transmission, needs belts, needs engine work of a non terminal nature [head gasket, etc].
That is why I've been looking at the Toro as this engine is a brand specific [Toro] labeled engine that not that many people know about, hence improving my chances by lowering the attention/demand of other prospective buyers [competition].
The Vanguard has just been the most often encountered of the four brands mentioned, I've seen a few Kohlers [expensive and rare, 1/4 as many and 2X as much $] Kawasakis [more expensive and more rare] and Hondas [as expensive and rare as the Kaw].
Vanguards just show up more often and would probably be a bit easier to install as the electrical connections would likely be the same as what is in my machine, though I'm not adverse to making some custom connections.
There have been several Toro 17-44 HXLs advertised and the prices for the whole machines have been in the $150-300 range, where a used Kohler CV15 [alone, engine only] is going for about $500. A Kawasaki 15hp v-twin is listed for $700 [and I'm not sure it'll fit].
So, I'm not scope locked on a Vanguard, it's just that they've presented themselves more often and for a more budget friendly price. That is why I'm trying to be able to quickly and easily ID potential donor engines.

I'm not sure that the blower housing [tapered down end over valve cover with the three pressed in ribs] is a definitive identifier of a Vanguard. But I'd have a difficult time believing that B&S would reshape the blower housing to increase their sales or model desirability.

I don't know where this will end, or what it will take to satisfy the question.
My Briggs service manual # 272147 which covers Vanguard singles DOES NOT include any 312700 engines. The biggest engine listed in that manual is the 28Q700.
The URL you cite in your opening post (link included below) as having confirmed that 312777 is a Vanguard, actually confirms (for me) that 312777 IS NOT a Vanguard.
Walt Conner states in that thread that while the engines listed in that thread are all the same physical size, none of them, including the 312777 are Vanguard engines.
I consider Walt Conner to be an authority on Briggs engines.

Here is a link that might be useful: Vanguard debate

I'm sure that you will find what will work for you and you seem capable of making it happen. Wiring is a work around- true. Besides physical size, exhaust is the next biggest. That is what the real pain of replacing a L head is all about- sans the price tag. A Command would sure be nice. I will say that if you go with the Toro intending to use the exhaust- the muffler is incredi-expensive should it be cracked or have broken baffles. On the blower housing, Toro was real big back in the day on touting that their engines were special. Another example was the CV twins on the 260 series of the same era. "Built to Toro's specs". Like Deere says, eh- send us what ya got left over. SO they put the pro filters on them....

the information listed below was copied from the briggs power portal.

Model Number
312777-0128-E1
Engine Series
VANGUARD

These were used on some craftsman models and I recall servicing some of them. A vanguard shroud was installed over the regular intek shroud using special mounting brackets. Check out the parts breakdown.

I don't know what upgrades were made to the regular intek to designate this as a vanguard.

Here is a link that might be useful: vanguard 312777-0128-e1

I've been looking. There are a few 17-44s that are listed with pics. Some of these engines have the Vanguard in the center of the debris screen over the fan. It is there as B&S had sold these engines to Toro and Toro had them labelled as 17hp power plus.
Now, I know that slapping a label on something does not make it that. But, B&S do put a Vanguard label on some Toro 17hp power plus engines.
I've also seen Inteks in these 17-44s and they look like Inteks, so we'll see when it comes time to buy parts, if I get this. I suppose that an Intek wouldn't be the end of the world, either.
Thanks for all the input, I'll update this as info becomes available.

With the info from bluemower, I looked at the last page of the IPL and saw that the manual for the 312700 series is 272147, which is supposed to be the Vanguard singles manual.
That is at odds with my copy of 272147 because the copy I have does not include 312700. It stops at 28Q700.
So, I guess if Briggs wants to call it a Vanguard, they can legally do so.
I think I'll start calling my Chevy work truck a Cadillac Escalade, after all, both share a common OEM and tooling.

None of the single cylinder Vanguards have panned out. I was asking around and got a line on a Husqvarna RB-H 160 with a blown transmission. It is a '96 with a 303777-1032-a1 v-twin Vanguard. This is an attempt to make a lateral move [part out this mower] to have a bigger bank for the real deal. 40" [102mm] vented counter rotating timed deck, rear bagger, good running v-twin 16hp Vanguard. Machine was only $100, so I got it.
The ? that I've got now is:
The plugs look a bit black. Most of the carb jetting has been leaned out so that a good running B&S will have ash grey plug. Black would indicate oil fouling. Vanguards are known to have head gasket problems that present as oil into the head, air cleaner, combustion chamber. How common and at what engine hours do these show up?
I'd assume that a '96 would have more than enough hours for this problem to show up, now I'm wondering if it might be rings. A head gasket is a lot easier to fix/replace than rings.
Any experience with this engine's wear characteristics and failure intervals?
B&S estimates 20-30 hours/season, but my experience is that that # is low. A '96 would have 17 seasons times 30 = 510 hours. I'd figure maybe twice that # of hours [aprox 1,000]. Is this engine poked ? Granted, care and maintenance has a lot to do with engine longevity, so best guess and speculation. I've only got a compression tester [which does not work well with compression release on valve train], any other way to check cylinder/head/ring integrity other than leak-down vacuum test on these?

Thanks, John

***"BLACK would indicate oil fouling"***
Not necessarily the exclusive deciding factor.
The black color only indicates carbon.
The source of the carbon will be revealed by other facets of the carbon deposits.
Carbon deposits due to lube oil will have a glossy look and will be quite gummy/sticky when scratched. Also the built up deposits can be quite thick and uniformly cover everything about the spark plug completely.

Carbon deposits due to a very rich fuel mixture are sooty and powdery looking, and when scratched, will readily shed dryish flakes or specks.
Often, where a rich mix is causing carbon, you might see places on the spark plug where the carbon has already flaked off or areas where the carbon seems not to be as thick.

A poor boy's method for testing/guessing at compression issues can be done using compressed air. If using this technique, you will need both valve covers removed.
You will need an adapter fitting that threads into the spark plug hole and accepts to being fitted to a shop air hose.
The engine must be rolled to the correct position (piston 1/4" down and beyond TDC point of the COMPRESSION stroke) for the cylinder being checked.
The engine absolutely MUST BE HELD FROM TURNING by some means to prevent the piston from reacting to the compressed air. You would have to figure out how to hold it with what you have on hand. An alternative method that does not require engine to be "locked" is described at the end of this description, so read carefully not to get the 2 confused.

Air pressure needs to be 90 PSI to 120 PSI for best results.
The air hose and all fittings need to be free of leaks as you will be "listening for leakage" in the test (and any air leaks in the plumbing can dull your testing accuracy).
Each cylinder must be tested individually and the piston for each cylinder must be in the correct point, which means you will have to go through the locking and unlocking of the holding device for each cylinder.
Once the engine is rigged against turning, apply compressed air to the cylinder you are testing.
Now, you must listen carefully for air leakage. I use a 3 foot length of 3/8" plastic tubing to pin point the leaking spot/area by using it like an impromptu stethoscope. Hold one end of the tubing near to one of your ears (but don't stick it in your ear) and probe the following places on the engine with the other end of the tube:
Get inside the valve push rod area of the cylinder head where the head meets the block. If the head gasket is leaking, that is where the leak will be.
If you hear air leaking, and it gets louder as you probe nearer to the head/block juncture, and begins to become quieter when the probe goes deeper into the gallery (has moved past the head/block juncture), you have located the leak.
But.....if the noise level continues to increase the deeper into the gallery the probe goes.............the leak may be coming from the opposite cylinder head or rings.
So you have to test BOTH cylinders the same way, but one at a time.
If you find that escaping air noise heard through the plastic tube increases on BOTH cylinders the deeper into the galleries the probe is inserted, and you do not hear an obviously louder sound when the probe tube end is positioned right next to either head/block juncture seam..........
the air is escaping past piston rings.
This test method will also identify valve leakage by placing the probe tube into the exhaust/muffler or the intake/carb locations.

There is also an alternative to rigging a holding fixture to keep the engine from moving under the influence of the compressed air.
The alternative way is to REMOVE the push rods from the rocker arms of the cylinder you are testing and simply place the piston at BOTTOM DEAD CENTER (BDC). With the push rods removed, the terms compression, power, exhaust, and intake stroke become meaningless, as both valves are closed.
The push rods must be marked so as to get them back exactly where they came from.
It only requires finger tip pressure to push the valve spring down to remove the push rods.

My thoughts on the Vanguards having "head gasket issues" are that the "true Vanguards" (and the 303700 is a true Vanguard) do not have any ill repute for head gasket failure.
On the other hand, the Briggs single cylinder OHV 280000 and 310000 engines DO HAVE somewhat a reputation for head gasket blow out. Same goes for the Briggs V twin OHV engines that are just based on having one more cylinder of the same design as the 28 and 31 OHV Intek family (405700 and 445700).

This post was edited by mownie on Tue, Feb 4, 14 at 12:02

Thanks for that, I'll get the compressor out. I've used air to remove valve springs to get at seals before, never listened for leaks before though.
When I first pulled the plugs, my heart sunk, as these plugs did not look good. I've "read" plugs to jet carbs before, and these looked oil fouled. Not dripping, engine still ran well [cut off limiter tab and got it to idle where idle speed screw was moot]. Adjusted valves and added oil [my first inkling], I usually put some series 3 or ATF into a low, new to me engine to clean out crankcase, then change oil to get a base line of oil use/consumption. I've had some experience with air-cooled [VW and others] preference for straight grade 30. So, what I'm hoping is that the black plugs might be a combination of clogged rings and multi-grade oil. I've got some Delo [diesel oil] in there now, and I'll change it to straight 30 and watch the stick. Right now, the engine is just sitting in the frame of a tractor/mower that's got a blown hydro trans, so it won't get any work for a while. Now, I've just got to figure out how to fit this into the space for a single, relocating the battery.
I thought long and hard about fitting this engine into this machine. If I were to get a single, it'd fit right in. But, the machine that I want to put this engine in is no Steinway, so a little hack-and-a-bush is well within proprieties. And you gotta love that v-twin sound [used to ride a Moto-Guzzi 850-T]. So, I think that I'm going to shoehorn this engine in. The v-twin Vanguards are way more common than the singles, so if an engine change is required to get a fresher engine, either a single or v-twin would fit.
The 12.5 hp flathead is 465cc [28ci], the v-twin is only 480cc [30ci], so displacement is not that much bigger, much smoother, quieter, and hopefully way better [less] fuel consumption [my primary goal in this project].
Now, just need to get some time to do the swap. Southern hemisphere is at the tail end of summer, grass is growing slower, so I can probably skip a week cutting grass, and get 'er done.
Thanks for all the help, John

Up here (USA) on the other side of the equator, we are eagerly awaiting (at least I am) the arrival of Spring :^)

I'll tell you, Christmas in summer was/is hard to get used to.
My parents [years ago] had a place in West Palm, Fla. My wife and I went down at Christmas one year. Sitting on the beach Christmas Day was weird.

I always enjoy seeing the Corona Beer ads at Christmas.
Christmas lights draping palm trees with the caption "Feliz Navidad".

I've run the V-twin with the Delo up and down, hot to cold a few cycles. My concern, other than the black plugs, was that there was a bit of a miss. Running on one cylinder for a while, while cold, and as it warmed up, a little pop/miss both at idle and at WOT.
Now that the engine has been semi-flushed, I did an oil and filter change. Found the filter at a Wal/K Mart type place after cross referencing the #s, and put some Castrol 30wt for air-cooled 4t OPE. The popping went away, it'll now start right up, often times without the choke, and idles on both cylinders right away, without the one cylinder warm up period.
So far, all that I've done was what should've been done as a part of normal maintenance; adjust valves, adjust carb [remove limiter on idle mix], change oil and filter [after high detergent oil added].
The plugs seem to be not getting any worse in the few times I've run this since, and actually seem to be getting cleaner/better around the center electrode [greyish tan] where before they were black all around, everywhere that the plugs were in the head [end of plug, positive and negative electrodes, porcelain insulator...]. I'm hoping that whatever oil was in there, was the problem, and now that the case has been cleaned and the correct oil and a new filter are on, it'll come right.
Now, I've just got to get the engines swapped over. There will be a bit of interference around the battery, but having looked at Husqvarna's manual for a Rider 14-Pro [that has a 14hp v-twin Vanguard] the engine cover and engine compartment look very similar. So maybe there is an offset that'll let it fit, as the difference in it fitting and not is fractional. Real issue will be the muffler. The RB-H 160 that this came out of was a front mounted engine configuration with a down turned muffler. Where there is space provided for a muffler on my machine is up and back. I'll need to turn the muffler up to where it is about even with the air filter. I figure that a cut and flip of the muffler will get most of the way. Then just some "U" bends to make the rest.
Thanks, John

sometime later...
Well, my wife got a[n] [awesome] job, in a different city. No need for the Rider, so was looking to sell. My neighbour [who had seen how good a job it did and how much time it saved] bought it from me for a grand. Not so bad for a $100 machine with a little sweat equity and some head scratching.
I'd bought another machine [16hp Husqvarna]for $100 that I scraped after snatching the engine off of it. Just sold the engine for $250.
All in all, this has been a very rewarding project, in many ways.

This forum has been very supportive, lots of very knowledgeable people on here that are willing to help.
Thanks again.

Congratulations to your wife on the new job, and to you for being a crafty (and lucky) man.
I usually have to count the earnings from my sweat equity in units of personal satisfaction. You, however, seem to have stayed several steps ahead of fate at every turn on this adventure and now count your dividends in $ units.
Best of luck to you and your wife for the future. :^)