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B&S DOV Engines

Posted by rdak z5MI (My Page) on
Wed, May 16, 07 at 8:38

Any opinions about this engine?

http://www.briggsandstratton.com/display/router.asp?docid=101512


Follow-Up Postings:

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RE: B&S DOV Engines

"No more struggling to start the lawn mower."
This is a quote right off there web page. Does this mean that they are admitting every single engine they produced up untill this break through was a "struggle" to start?
What happened to "Prime and Pull easy starting system"?
If they spent more time/money on consentrating on building good or even great engines and less time trying to "fool" the public with catchy phazes and sneeky marketing they'd be doing better.
Thats what I think about this engine, thanks for asking.


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RE: B&S DOV Engines

Hello Radak,

My impression is Briggs has developed this engine for the next phase of emissions controls. I also believe Briggs wants to upgrade some of their engines for better starting - to better compete with the easy starting Honda and Kawasaki engines. I examined a disassembled DOV during a Briggs update, and it appears to be a simple design that should be easy to service. I believe the engine will be available with the primer system and with the ready start system.

The conventional primer system is used by Briggs, Tecumseh, Kawasaki, and perhaps a few other manufacturers. A primer bulb is used to pressurize the float bowl and some fuel is pushed up the fuel pickup tube to the venturi area. The correct number of primes is a guessing game - depending on the outside temperature and the quality of the fuel.

The Ready Start system has a choke that is spring loaded closed. Connected to the choke is an air vane that opens the choke when the engine starts. There is a bimetal temperature sensor that further controls the air vane position. This system also uses a small venturi carburetor that draws fuel into the intake manifold at very low starting rpms. Finally, the ignition coil has been redesigned to produce a strong spark at very low starting rpms.

There was discussion at the PERR site.

http://perr.com/forum/viewtopic.php?t=6038&highlight=dov


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RE: B&S DOV Engines

'"No more struggling to start the lawn mower."
This is a quote right off there web page. Does this mean that they are admitting every single engine they produced up untill this break through was a "struggle" to start?
What happened to "Prime and Pull easy starting system"?
If they spent more time/money on consentrating on building good or even great engines and less time trying to "fool" the public with catchy phazes and sneeky marketing they'd be doing better.
Thats what I think about this engine, thanks for asking.'

Why should B&S be honest when no other manufacturer or vendor of anything in the entire history of the U.S. has been? Every single thing in any advertisement, commercial, political campaign or 'info-mercial' is a lie. This has now spread to the entire world. It is so pervasive that plain, truthful language used in factual descriptions of things for sale is no longer believed - it is thought to be a clever ruse to obfuscate the truth. I often dream of a boring world where 'advertisements' are simply black & white statements of fact about a new product. Vehicles all have model numbers - no 'Potenza', 'Modena' or 'Fiero'. In this world you accept the product description as the literal truth and decide if it meets your needs. Unfortunately, it will never happen. People are stupid and insist on being 'sold' products rather than selecting them intelligently. Every engine manufacturer will always call every engine 'Easy-Start' because that is the #1 attribute the 'sheeple' are looking for in a mower engine. Remember the Sears 'Eager One'? I think they started it for 4-cycles, but Lawn-Boy called their 2-cycle mowers 'easy-starting' for many years. So, what's the truth? As always, you have to buy it to find out, at which point the advertising agency high-fives each other as the cash register goes 'Ka-ching'.


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RE: B&S DOV Engines

I think you guys are over reacting. Briggs and Stratton engines have gotten easier to start with almost all design changes over the years. The new design changes in the DOV engine make sense to me. I hope they can continue to be on the forefront of technology. Even if they may exagerate some things for "press" I prefer to swallow a little glorification of a product as opposed to seeing them go down making flatheads. I hate to see the day when all our tech comes from the far east. Go Briggs and Statton...Go USA!


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RE: B&S DOV Engines

Go USA??? I've heard B&S is shutting down plants in favor of foreign production.

http://biz.yahoo.com/bizj/070419/1449550.html
http://www.jsonline.com/story/index.aspx?id=593775
http://milwaukee.bizjournals.com/milwaukee/stories/2007/04/16/daily36.html

I'm not happy to see this either, but it is reality.

I wonder if this new technology means this engine is available in California without changes???


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RE: B&S DOV Engines

On the Briggs site they say "The engine is "best in class" when it comes to cutting grass, producing peak torque of 11.4 N/m at 2.400 RPM."

Two point 4 RPM? That is pretty darn slow. But lets assume that they really mean two thousand four hundred (2,400) RPM, that is very slow for a lawn mower. I am a little curious about how it will mow at such a slow speed, especially mulching.

As to the Ready Start system, isn't that amother fancy name for the system that they had in the late 70s or early 80s? We had several of them back then. The carb-on-tank setup, with a vacuum operated automatic choke. The spring closed the choke, and intake vacuum pulled it open. No priming, no choke on the throttle. Just put it to fast and pull. I don't remember them being hard to start, either.


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RE: B&S DOV Engines

great -just what we need automatic chokes for lawnmowers-just more stuff to go wrong .


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RE: B&S DOV Engines

No, really, the automatic choke that Briggs used years ago was great. nothing to go wrong really. There was a vacuum diaphram under the carb (it was actually part of the gasket I think), and when you started the engine the diaphram pulled the butterfly open. As the engine came under a load the vacuum would drop and it would choke a little, giving it a little more fuel like an accelerator pump in a car.

I do not know if this is like what they are calling Ready Start, but I'd bet that it is similar. It is nothing new though, as it was around 25 to 30 years ago.


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RE: B&S DOV Engines

Ready Start uses a spring to close or create choke as default. Then two old systems are used. One the bi-metal choke spring which increases or decreases closer tension to supplement the main closer spring.

The second old system brought back is adapted from the old air vane governor. The air vane instead of closing the throttle as more air passes it, in this case it opens the choke as more air passes the vane.

This system works pretty neat. If the engine is cold and ambient air is cold the bi-metal spring keeps the choke closed a little longer. If warm it allows the choke to pen quicker.

Upon starting the flywheel fan moves air across the air vane and starts to open the choke. By the time the engine rpms are at running speed the choke is wide open. Should a cold engine stumble and slow down the choke starts to close again.

The overall system works far better then I expected it when they first talked about it at update school a couple of years back. It prevents over choking by someone slow to respond to a manual control choke and automatically re-chokes if needed to prevent a cold stumble from turning into a die off and need to restart. Perfect system for dummies.


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RE: B&S DOV Engines

thats the whole problem -too many dummies using mowers. just like the idiots who couldnt use the choke in their car and so we suffered for decades with the poorly desighned automatic choke


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RE: B&S DOV Engines

  • Posted by rdak z5MI (My Page) on
    Thu, May 17, 07 at 21:11

Thanks for the info. and link Larry.


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