# Briggs and Stratton engine lacks power



## amac (Jul 19, 2008)

My B and S lawn mower just received carb service a couple of weeks ago and was running fine. My son started mowing lawns which increased its usage and then one day the engine, though it runs, seems to have about half the power it did before. It is a lot quieter, which is nice, but stalls at the sign of higher grass and has little power. Any suggestions? I cleaned the air filter and it seemed to help a little.

thanks.


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## K-B (Oct 24, 2005)

What kind of mower? Walk-behind? Tractor? How many horsepower?
A lot quieter...hmm. Check the muffler, it might have gotten plugged. Mud wasps have a knack for plugging mufflers overnight.


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## A#1 (Jul 13, 2008)

amac said:


> seems to have about half the power it did before. It is a lot quieter, which is nice


check if the throttle cable mechanism has slipped...just from your explaination...half the power...quieter...sounds like the throttle cable isn't opening the throttle lever on the carb all the way


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## Stealthy (Aug 7, 2008)

Checked cable mechanism, thanks but did not fix the problem. Now when I push down on the back of the mower and raise the front (like you would when you are turning) it dies. BTW, it is a 4.5 hp push mower yard machine.


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## A#1 (Jul 13, 2008)

carb service and extra usage...i hope your small engine mechanic is capable of setting the air/fuel ration mixture with the screws that set the mixture...an over rich air/fuel mixture...being too rich on the fuel side can wash away the lubrication on the cylinder wall...this would score the cylinder wall and cause loss of compression...

other causes that come to mind...possible the governer adjustment as lost it proper adjustment...

if it's a new enough mower...some new small engines have a kill switch which works in coordination with the crankcase oil level...if the engine is a little low on oil...tilting it may trip this sensor and cause it to shut down to prevent engine failure.

other than that...burnt exhaust valve...could be many causes...for the price of a sparkplug...i'd start there if it hasn't been replaced in a while...many a problem comes down to a weak spark due to the electrode and conductor on the sparkplug being worn and its arc gap then is out of tolerance giving a weak spark...


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## Basementgeek (Feb 7, 2005)

Have you thought about taking it back to the place that serviced it ?

If it ran ok before it was fixed maybe they messed it up - sounds like a fuel problem to me.

BG


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