HELP Please...it caught fire

[KennyV]

The bad news, the idle is kinda higher than expected and once you crack the throttle opne a hair bit more, the engine wants to rev itself to death.

Out of curiosity, I turned the airscrew all the way in while it was idling, this shoulda killed it but it kept running.

Have you felt resistance on the governor arm with the engine running... Is the governor actually working?

Have you taken the screw and it's seat completely out to check if the point is damaged?

You can easily swap engines but this one needs to be figured out... too strange. :smile:KennyV

 

[inline300]

I would say there was some resistance with the governor arm when it was running. Governor moves freely when not running.

Air screw tip was fine.


Should the carb butterfly open fully when the throttle control lever is set to FAST?

 

[KennyV]

Should the carb butterfly open fully when the throttle control lever is set to FAST?

Yes is your linkage allowing it to fully open?

 

[inline300]

I know it seemed like a basic question but I had to ask.

Yes, linkage works fine now.

Im still at a loss. Gonna put a new governor spring on it while Im throwing money at it.

 

[jhwentworth]

And just so Im 100% sure, if the throttle lever is set to the fastest speed, the carb butterfly should be fully open or no? Im thinking no, as I believe the governor is meant to increase the engine speed by opening the throttle, if the engine is put under load, say cutting tall grass all of a sudden, so Im thinking if the throttle is open all the way under the fast lever setting, then the governor cant open the throttle any more? Thoughts?
.

Small engine governors work by limiting engine RPMs. If you removed the governor's connection to the throttle platem and had the throttle level full on, the motor would rev very high, for a while. The throttle lever is trying to open the throttle plate and the governor is trying to prevent that. The higher the engine RPMs the more force the governor applies to counteract the pressure from the throttle lever.

When you open the throttle lever with the engine not running the throttle plate should be wide open. After the engine starts and increases RPM the governor should start to move to limit the speed. If you move the governor can you limit engine speed? Is the governor moving with engine speed changes? The internals of the governor do break, and the symptoms would be what you're seeing.

The problem you found with the idle screw cranked in is quite common. People use the idle adjustment to cover up a problem with low speed stalling or rough running.

 

[inline300]

Gotta love troubleshooting


I just went out, fired the mower up, this is what I experienced.


Engine NOT running.
Governor arm moves freely back and forth.


Engine RUNNING at IDLE.
I can physically move the governor arm with no resistance, and make the engine rev up and down. Otherwise, it idles fine, little on the high side but good, nothing unusual at this point.


Engine RUNNING at fastest position on the throttle lever.
Carb butterfly opens fully, Governor arm moves clockwise as far as it can, and at no point moves counter clockwise to slow down the engine.


Houston, I think we have a problem.:laughing:

Now my question is, is this a swap in and out type deal or will I need some special tool or information to replace? Could there be something else causing the governor itself not work?
What makes the governor work? When I look at the part diagram, it looks like a shaft with a canister hanging off it? Part #616
Parts and Diagrams for Briggs and Stratton 286707-0437-01



Thanks

 

[KennyV]

Gotta love troubleshooting



Engine RUNNING at fastest position on the throttle lever.
Carb butterfly opens fully, Governor arm moves clockwise as far as it can, and at no point moves counter clockwise to slow down the engine.



What makes the governor work?

Thats why I was asking about the governor showing resistance when the engine was running... If it isn't it is going to be internal, but an easy (sort of) fix... watch this youtube...
YouTube - how a governor works
I think you are on to a fix... :smile:KennyV

 

[KennyV]

BTW it could be that arm #616 ... but most likely is the gear part that spins and pushes against the end of that arm...
You will need to take the end case off to see what is not right... Not really a terrible job. :thumbsup:
Take care not to score the main seal when you remove it, or you will end up with an oil leak...
:smile:KennyV

 

[inline300]

Well fellers, right after I clicked the submit button this morning, I decided instead of guess what na hell is inside these motors, Id just find out. :biggrin:

So maybe I took the flywheel off and realized I didnt have too but, now I know. haha

I finally realize how the governor works.

It also took about two seconds to realize why it wasnt working, the plastic gear is worn.

Guess Ill pick one of those up. I havent looked but surely to goodness they sell the gear without having to buy the other pieces.

Your right kenny, if I had understood what you were saying, I would have isolated the problem right away but I just had no idea. I should have asked for specifics but I didnt, I felt resistance clockwise due to the spring on the throttle linkage but what I didnt realize till this morning, is the resistance should be counter clockwise, forcing the throttle to close or lower.

Well folks, your help has been appreciated.

Thanks

 

[briggs]

this is how we all learn glad you found the prob ....let us know what happens