Small Briggs Engine help...

[rback33]

I have a 23HP (I think) on my Garden Tractor... I have drained the tank, checked the fuel filter and changed the air filter. What is does is basically surges when it runs... it did this last summer and I eventually got it to basically quit, but never felt that it ran at Full RPM like it should. I know next to nothing about small engines and hope to have a buddy of mine over to work on it this afternoon. When it is doing what it does there is a little arm near the carburetor that slides back and forth in time with the surging..I found this last summer when i was working on it... I tried carb cleaner last summer and that did not seem to help. Any suggestions are appreciated.

ps.. I can mow with it the way it, but I can tell I am not getting full blade speed and it's not cutting as well as it should and bogs down much easier as well.

 

[firemanpat2910]

sounds like the governor needs adjusting,or a new spring. There are several books on smallengine repair that would probably help you. I remember seeing one at Home Depot that had a lot of pics diagrams. There is definatly a trick to getting rid of the surge. Its a combo of carb adjusts and govenor.Also vacuum leaks can cause problems.

 

[TBDonnelly]

I have a 23HP (I think) on my Garden Tractor... What is does is basically surges when it runs...

I also have a 23hp on my garden tractor. Mine also had a surge issue. Spraying carburetor cleaner in the throat of the carburetor fixed the issue temporarily at best. I started adding a small amount of STP fuel injector & carburetor treatment in with the gas. The surging issue has stopped ever since. I believe it was a gum build-up issue in the carb....

Don

 

[Bird]

The only times I can remember having that problem was with much smaller Briggs engines and, as the fireman said, it was the spring on the governor.

 

[MT372HERE]

Sounds to me like yo uare running lean.

Id pull the carb and clean the main jet out.

Before you do that, rev it way up to full throttle, then slam the choke shut. Do this 10 times and see if it gets any better.

I had a 21 (I THINK) hp intek briggs that did this, as well as dozens of smaller briggs, always was the main jet, or the pilot jet.

 

[rback33]

I've been thinking it was a fuel/carb problem..m I'll try some of this when I get home... have some carb/injector cleaner in the back seat of my ca r that I leave in town... I will grab it before I run home... thanks for the help... I'll try and update on Wednesday....

 

[Parttimer]

I have just encountered the same problem with my father's craftsman 15.5 hp lawn tractor. After mowing some long grass, the engine is cycling. I checked the air filter, fuel filter, spark plug. The plug indicates a little lean but not bad. There is an arm that comes out of the base of the (engine,tranny) which is moving and throttling the butterfly valve at the exit of the carborator. Seems to be something that has somthing to do with load sencing to adjust for a heavy load on the little engine??? Looking for a schematic for the tractor to see what this does. Seems like you are having a similar problem. Did any of the other solutions help your issue?? just curiouse.

 

[firemanpat2910]

parttimer, That is the govenor. it can be very touchy to adjust. First eliminate all fuel, carb,and air flow issues. If problems not cured you might need to adjust the gov. Sometimes its as easy as replacing the spring other times it an hour or more of adjust a little,test adjust,test,......... Its very aggrivating especialy when its 110 degrees out.

 

[Parttimer]

Thanks, My dad and I were thinking this was the origin of the problem. Next time I'm over there I will take a better look under the mower and see what is there. My mother cleaned up and threw away the owners manual for the new mower and kept the 20 year old one. LOL.

 

[HomeBrew2]

My 1992 MTD w/ 16HP B&S does the surging thing every year or so. It has always been a simple fix of turning the carb mixture screw in a bit then back out. I agree with a lean condition, thus the gov trying to compensate. Also agree probably dirt in carb but tweeking the screw seems to dislodge it. 10 sec fix for me.
Cheers!

 

[rback33]

Sorry, just now came back to check the thread again.. it's better, but not "fixed." I'll try adjusting the screw slighlty when I mow again (if.. it's SOOOO dry here, but got 3/4" the other night) Should know this weekend...

 

[Thomas]

Some darn good advice was given...soooo I'll give it a shot.
I had 19.5hp doing the samething and come to find out the choke wasn't opening all the way...after tractor warm up lack of rpm's to cut...spray some WD40 into cable no more problem.

Since you and your dad are having the same problem,just wondering if fuel being purchase from the same gas station...maybe try another gas station??

 

[rback33]

Well as Mr Murphy would have it... it's been BONE dry in Kansas all summer and it has rained for the last 3 days..... didn't so much as glance at the mower with all the wet stuff around....

 

[MT372HERE]

Try this.

Take the air Filter off. Start the engine, and rev it to full throttle, and put your hand firmly over the intake, completely chokeing the engine.

This will create a strong Vaccum, and suck any crap through the jets.

It is not a Governor problem, the fact the governor is working proves that. What is happening is the Engine is running at say 3000 rpms, and it runs lean to the point it cant run any longer and start to slow, thusly, the governor opens the throttle, allowing the carb to draft stronger, and pull more fuel up, it recovers, and closes back down.

Typically, the jets are a little gummed, and causes it to run slightly lean, with todays CARB and EPA laws, they are lean from the factory, so there isnt alot of room to play with before it hunts.

If the governor wasnt working, the engine would run lean, then shut off.

If you run it slightly choked, does the hunting condition go away?

 

[Parttimer]

I ran a half a can of Seafoam carborator cleaner with a tank of gas and now the engine is only surging when the mowing deck is not engaged. The engine seems to run nicely during mowing. Thanks