Briggs and Stratton engine

Joe390

Hi , I have a Briggs and Stratton 15.5 intek engine in my lawn mower. It has started over reving up to 3550 revs. When it is cold it is fine and starts no problem. But once it runs for awhile it starts to surge and then over revs. I have tried a new air filter , fuel filter , cleaned the carb and even got a new carb but with the new one it idles perfect but once reved up surges like mad. I can manage to keep the revs down when it's under load with the deck on , but once deck is disengaged it climbs back up. It is fairly gutless aswell and has no real power anymore.
Any insight would be much appreciated. Thanks

mikeecho

Try dipetane, it's what everyone's using to fix everything. :cool:

AMKC

Maybe the governor on your lawnmower is not set right. I am no mechanic but I do know it is there to control the revs.

Jeff2

Check for an air leak between the carb and intake.

Joe390

Hi , I have checked for leaks and no leaks atall. How would I check the govener?

Lewis_Benson

The governor will be a vane like piece that is close to the flywheel , it will be pushed out by the fans on the flywheel while the engine is running.
It till be connected to the throttle linkage.

It may be in need of adjustment.

Henry Ford III

Joe390 wrote: »

Hi , I have a Briggs and Stratton 15.5 intek engine in my lawn mower. It has started over reving up to 3550 revs. When it is cold it is fine and starts no problem. But once it runs for awhile it starts to surge and then over revs. I have tried a new air filter , fuel filter , cleaned the carb and even got a new carb but with the new one it idles perfect but once reved up surges like mad. I can manage to keep the revs down when it's under load with the deck on , but once deck is disengaged it climbs back up. It is fairly gutless aswell and has no real power anymore.
Any insight would be much appreciated. Thanks

How did you measure the rpm?

Ubbquittious

Does this engine have a wax cylinder choke by any chance? Could be carb problem

Joe390

Henry Ford III wrote: »

How did you measure the rpm?

Got a rpm gauge on it

Joe390

Lewis_Benson wrote: »

The governor will be a vane like piece that is close to the flywheel , it will be pushed out by the fans on the flywheel while the engine is running.
It till be connected to the throttle linkage.

It may be in need of adjustment.

Is the governor not weights inside in this engine?

cena

Sounds like the screw on the carb needs adjustment

Joe390

cena wrote: »

Sounds like the screw on the carb needs adjustment

I was trying to adjust it. It only has a air fuel mix and an idke set screw . I can turn the air fuel mix all true way in and then All the way out and no difference , a slightly less over rev maybe but nothing major

Jeff2

As I said air leak between the carb and intake.

Spray wd40 on the intake and try start it .

If it smokes then there an air leak.

Wash the when wd40 off after.

Joe390

Jeff2 wrote: »

As I said air leak between the carb and intake.

Spray wd40 on the intake and try start it .

If it smokes then there an air leak.

Wash the when wd40 off after.

Ok I'll try that tomorrow and let u know. Hope it is as it's getting frustrating now. Thanks

Jeff2

An air leak lthere let's the engine rev but with no extra fuel it has no extra power as you describe.

Joe390

Jeff2 wrote: »

As I said air leak between the carb and intake.

Spray wd40 on the intake and try start it .

If it smokes then there an air leak.

Wash the when wd40 off after.

Tried that today and no leaks that I can make out. Took off the intake tube and inspected gaskets and tube again , no cracks and tube is holding pressure when blow into. Thanks again