I have a lawn tractor with a Briggs and Stratton 12 hp model 281707 engine. The engine is hard starting when cold. It chugs for a bit until it gets going. Sometimes it chugs and stalls. After the engine is warm it starts ok. The gas is fresh. The choke seems to be working ok. I tried starting fluid thinking it was a carburetor problem. The starting fluid didn't help. The air cleaner is clean. New sparkplug. The compression is low when the engine sits 30-45 psi.
After the engine has been running the compression goes to 80 psi. I squirted oil in the cylinder and the compression went to 80 psi when cold. After addin the oil the engine started fine two times, when I cut the grass. On the third time the engine was hard to start again and the compression was low. This occured over a couple of weeks. I'm thinking head gasket. Is there any way to tell for sure before I take the engine apart? Or do you think I may have another problem?
:confused:

Sorry I click on the wrong Forum

:drunk:

ill by it give me a price

This post was intentionally remove by "certifiedtech"

Sound like the valve clearance is off causing a compression leak.
Remove valve cover/crankcase breather (behind carb,). Remove spark plug and set the engine to "top dead center" With the piston at the top and both valves closed. With a feeler gauge measure the distance between the valve stems and lifters
(Intake "min 5" "max 7" use 6)

(Exhaust "min 9" "max 11" use 10)

In other words

Intake 6
Exhaust 10

Most likely you`ll need a valve job.

you can set them with one valve open all the way , if the intake valve is all the way open set the exaust, when the exaust is all the way open set the intake . if you just find top dead center on the piston there is a chance it wont be on the compression stroke , you want the flat side of the cam ! it dont sound to me like the engine needs a complete valve job just yett . is the throttle shaft in the carburator tight? did the engine smoke like a house on fire ? with compression that low dry , then that much wet that would indicate a ring sealing problem the cylinder wall might be scored . valves could verry well be the problem , but the compression should not jump up that much with wet dry test if it was the valves , how much oil did you put in the combustion chamber ?

the valves just need to be adjusted that will involve pulling head and valve cover this has been my experiance

Try checking the head bolts to see if they are snug. Sometimes this can cause a loss of compression and/or eratic engine operation.

Look for:

1) Loose head bolts
2) Loose spark plug
3) Blown gasket/broken gasket
4) Incorrect valve clearance
5) Worn rings

how much you want for the engine?

how much you want for the engine?

It may be too late, the original post is a couple of years old.
thanks,

well than lol
hummmmmmmmmmmmm................