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Valve Gap Adjustment as Regular Maintenance

Posted by optsyeagle (My Page) on
Sat, Nov 1, 08 at 9:05

I was watching a guy adjusting the valve gaps on a riding mower on youtube and he said that with Briggs & Stratton motors, he recommended doing this once per year. He said they just normally go out of adjustment.

Does anyone else recommend this and what benefits would be derived from a mower that appears to be working just fine.


Follow-Up Postings:

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RE: Valve Gap Adjustment as Regular Maintenance

"Does anyone else recommend this and what benefits would be derived from a mower that appears to be working just fine."

I THINK B&S recommends it and the benefit is that the engine doesn't gradually get harder to turn over overloading the starter and eventually damaging the starter or result in engine not turning over.

Do I do that - no.

Walt Conner


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RE: Valve Gap Adjustment as Regular Maintenance

Thanks Walt.

I guess this gets added to the catagory that also includes saying a person shouldn't drink a lot and run around with loose women.


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RE: Valve Gap Adjustment as Regular Maintenance

! do this and you may never wear your tractor out! IMO I would also add removing wheels, cleaning axles, and hubs and lite coat of high temp grease, changing the fuel filter, and about every two or three year remove the fuel tank and clean it out (you'll be suprised what you find in there) and inspecting for chafed wires.

Course Everybody here knows I am a oil changing nerd, so chaining the oil atleast twice or three times a year is a must reguardless of hours, atleast change the oil filter once a year.

Are your familar with monthly pre-ventive maintenance requirements??? Some would be clean and inspect the air filter, check and sharpen blades and checking for grass build-up under the deck (especially if you have a habit of mowing when the grass is wet), lightly grease the grease points, check air in tires, and blow it off after every use. IMO this keeps the dust to a minimum and your lawn tractor looking like new and slows the aging process, especially if you store it inside.

There would also be "before use inspections" IMO. like check oil and gas, inspecting the deck belts, freedom of movement of blades, and going over your yard looking for sticks, rocks, toys, golf balls ect.. and any metal objects. these will become projectiles if you run over them. And the Most important IMO!!!!!!!!!NO KIDS IN YOUR YARD or the guy next door and exit your grass away from streets and sidewalks. Kind of long and I'm sure I forgot something, but I got time to kill before the big game TTU and TU.


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RE: Valve Gap Adjustment as Regular Maintenance

You can go through these threads and find many instances where the [oster wonders why their Briggs doesn't want to turn over.
Many times their second sentence is something like "I replaced the battery, solenoid and starter"!

I think I've seen recommendations of doing it every 100? hours?

One problem is that the slow/hard cranking develops slowly over time and thus isn't readily apparent. Lets face it, by the time a valve adjustment may be really needed, the battery is probably old enough to be considered suspect anyway.

On another forum, some one conducted a starter draw test on their engine with it locked up VS valves properly adjusted etc. Current draw was something like 300 AMPS VS 100 AMPS@

Say your engine is drawing 200 AMPS, but cranks over enough to finally start. Imagine the additional heat that starter generates.

In a nutshell, if my engine had 100 hours since the last valve adjustment OR it seems to be cranking just a bit slower, I'd adjust them. It may save buying a new starter motor down the road.


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RE: Valve Gap Adjustment as Regular Maintenance

The "gradual loss" factor also rings true in regard to keeping your engine at maximnm power efficiency. If the valve lash has decreased enough to prevent the compression release from operating as designed......the engine is not "breathing" as well as it could. This could be a 1 to 2 (or more) reduction in maximum horsepower output on engines advertised at 18HP or greater. Of course, everything else bill kapaun stated, holds creedence also. I just wanted to add another benefit gained by keeping your valves in as good a "state of tune" as the other stuff folks call "normal maintenance".


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RE: Valve Gap Adjustment as Regular Maintenance

Is there a similar valve adjustment recommendation for Kohler Command's? Particularly single cylinder 16hp? I don't think I have noticed this suggestion except for B&S twins, but the idea would make sense.


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RE: Valve Gap Adjustment as Regular Maintenance

Well all B&S OHV engines have mechanical lifters which need periodic adjustment. Kohler OHV engines have hydraulic lifters which adjust themselves like automobile lifters do.

Walt Conner


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RE: Valve Gap Adjustment as Regular Maintenance

Thanks. I know the Kohler is hydraulic, with the occassional Kohler "tick" and there is nothing in the Kohler manual about adjusting, but I didn't focus on the fact that B&S was mechanical. I just assumed they were also hydraulic these days, and that there was still some form of periodic adjusting recommended by those in the know. Now I "know".


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RE: Valve Gap Adjustment as Regular Maintenance

  • Posted by jerryo z4 in SE MN (My Page) on
    Mon, Nov 3, 08 at 21:33

Posted by walt2002 (My Page) on Mon, Nov 3, 08 at 17:15
Well all B&S OHV engines have mechanical lifters which need periodic adjustment. Kohler OHV engines have hydraulic lifters which adjust themselves like automobile lifters do.


So B&S intec's need adjusting every 100 hours or so.

Are the vangaurd's the same?

JerryO


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RE: Valve Gap Adjustment as Regular Maintenance

What about the Kawaski 20hp in a JD 425? Mech or hydraulic?
Fred


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RE: Valve Gap Adjustment as Regular Maintenance

Walt -
While the Kohler Command engines feature hydraulic lifters, the Kohler Courage series do not.
OTOH, I haven't sen instances (yet) of where the Courage engines need adjusting similar to the briggs... Perhaps others have ?


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RE: Valve Gap Adjustment as Regular Maintenance

Wherecan you find step by step instructions for performing valve lash adjustments. I could not find anything on the briggs web site other than to check and or adjust every 100 hrs. Thanx!


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RE: Valve Gap Adjustment as Regular Maintenance

I have detailed instructions for series 28 and 31 B&S engines. I have 4 pages copied from the B&S Repair Manuel for Intec V Twins.

Walt Conner
wconner5 at verizon dot net (put in proper format)


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RE: Valve Gap Adjustment as Regular Maintenance

jerryo, yes, the Vanguard engines have "solid" or mechanical tappets and require periodic adjustment to compensate for "valve stem stretch", as well as wear to the valve face and the valve seats in the head, all of which conspire to reduce the necessary "clearance or lash" (necessary for good compression and for the health of the valves and seats).


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RE: Valve Gap Adjustment as Regular Maintenance

Thanks Walt,but I have the 18hp vangaurd motor.Likely close to the same regiment,but if anyone knows for sure I would be thankfull. Thanx again.


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RE: Valve Gap Adjustment as Regular Maintenance

goblin127: I also have an 18 hp Vanguard. I asked Walt to send me the directions, of which he did. It made a great deal of difference on my engine once I readjusted the valves. He does know his stuff as well as many others here. E-mail him for the directions.


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RE: Valve Gap Adjustment as Regular Maintenance

what are vavles torqed at on cv22s


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