Engine Surge on LT40HG25

[ronwood]

My 25 HP Kolher engine appears from the sound of it runs above its normal top speed when I start the cut. I have a tach (Tiny Tach) that I bought from Kohlar and it looks like that it goes up to around 4200 rpm and then settles down to it normal range around 3700 rpm. It appears to happen more when the fuel tank is under 1/3 full. I have not replace the fuel filter yet . Have around 630 hrs on the mill. Any thoughts or suggestions would be appreciated.

Thanks
Ron

[Modat22]

Might be running a little lean or there is a little bit a wear on the butterfly pin in the carb. Shouldn't have wear at 630 hrs unless there is a plastic bushing in there. Put a new fuel filter on it and or drain the carb bowl (if it has a drain) and see what happens.

[Snag]

Any time I have seen that happen (not on my engine though  ;) ) the governor spring was not set correctly.  Do you have your kohler manual?  They have a troubleshooting section in them.  If not you can get them electronically on kohlerengines.com  

[ronwood]

Snag  - Thanks I will get the manuals.
Modat22  - Working on getting a new filter and try that. I don't think I have a bowl on the fuel line. If not probably be a good idea to have one.

Ron

[Modat22]

I ment the bowl on the carburator if it has one.

[D._Frederick]

Check the linkage from the governor lever to the butterfly valve on the carburator, there should be no play. If there is, get a very small spring and run it between the governor and the carb. to take up any play.