3000W Chinese Gensets Info.

Cox89XJ wrote:
Thanks professor, I think your right on the compression release.
I had an old International lawn mower with a 14hp Koler engine. That is the last engine I’ve rebuilt. After reassembly it would not run good. On the Koler I had to completely disassemble the motor to replace the governor. Is the compression release in the head or does the motor have to be completely disassembled?

The motor has to be completely disassembled. The release is on the camshaft. The exhaust valve is held open a little bit when you try to start the engine, as the engine picks up speed the centrifugal force on the counter weight pulls the release out of the way and the exhaust valve works normally.

It is possible for the mechanism to get stuck and not release as engine speed increases. You said you had electric start - if you put a compression tester meter into the spark plug hole and crank the engine for about 30 seconds you should reach 75 psi. If the thing is stuck, you will only get a reading of around 20 psi.

This is a photo of the mechanism on the camshaft. The blue arrow shows the centrifugal counter weight. You can see the spring in the background that pulls the compression release up.

The second photo with the blue arrow shows how the mechanism lifts the cam tappet to crack the exhaust valve. As engine speed increases the centrifugal force throws the counter weight outward and overcomes the tension of the spring.

I would just remove the assembly from the camshaft or grind/cut off the lifter tab rather than try to replace it. It will be a little harder to pull start but we have been doing that for decades on other engines.

If you decide to open it up you will probably need a new side case gasket. The thickness of the gasket is critical to the crank seal. If you try to replace the gasket with RTV the crank seal will be too tight on the crankshaft. The clue for this condition is you will not be able to turn the engine over by hand. An open side case is shown in the third photo.