help please 7.25 briggs idle too fast

[edwardh1]

I have a about 5 year old 21 inch walk behind snapper mower with a Briggs 7.25 ex 190 engine. it has a handle mounted lever engine speed control. the lowest I can set the speed at seems much too fast. Based on my owning mowers for 30 years.

is there a governor inside the engine that sets the speed the engine runs at? I tried loosening the push cable on the side of the eengine but it just got faster

 

[maxdustington]

On most small engines I have seen, there are multiple positions for the throttle cable to attach on the plate to accommodate different applications. You could try a different one, but I have a feeling your throttle cable might be stretched.

 

[mk378]

Much of the governor system is outside the engine on top of the carburetor. Remove the air cleaner box to see it better.

The user's control (if equipped) moves a lever that pulls on one end of the governor spring. Moving it toward faster makes the spring tighter. Moving it to an idle position should make the spring completely slack, so the throttle lever on the carb can easily go to the closed position.

Check that nothing is jammed. You should be able to pull the carb throttle closed against the spring. After starting the engine with no load, it should run with the carb throttle nearly closed.

Curious why anyone wants to idle a push mower.

 

[edwardh1]

mine is a self propelled. did not mention that

 

[JTK]

edwardh1, my 7-8yr/old 21" Snapper commercial mulcher is the same way. The throttle lever on the handlebar only ranges the engine speed from high to max RPM. I typically mow with the throttle all the way back. Seems odd, but I've never been ambitious enough to look into it given it runs and mows so well as is.

 

[andyd]

Doubt if wire is stretched. You could, I suppose, but this cable is a solid wire that is pushed and not stranded like a brake cable that pulls. There should be a linkage adj at carb. Also an idle stop screw that could be backed out. This is generic, advice.

 

[eljefino]

The lever goes to the governor. The governor goes to the carb.

Since it's all spring loaded, mess around with it and see if you can get the low idle you want just by poking around in there. Then you'll know if it's truly the governor, which I think it is. There should be various stop screws you can back out.

The engineers may have a reason for a mid-high idle such as fan speed for cooling or getting the oil flinger to lubricate properly.

 

[old1]

On many of the newest engines they are purposely made to idle high for emission control, as the normal idle circuit is the richest circuit in the carb. If you notice, many newer engines don't even have a remote throttle.

 

[eljefino]

Well yeah and if it's cammed for a specific RPM, the intake and exhaust and all that will be tuned for said RPM. Small engine carbs vary widely in complexity and something constant-speed like a lawnmower will have a different emulsion tube than a go-cart. And less ability to cope with sudden transitions in load requirements.

If it's too low an RPM, vacuum will drop, and the carb will enrich, wasting gas and causing unnecessary emissions. How often do you idle without working anyway?

 

[Lubener]

Some engines have a coil spring connecting to the governor lever also, could be broken, missing or disconnected. I highly doubt the governor has gone out of adjustment on its own.

 

[old1]

If the governor spring is broken, it will idle all the time.