compression release valve

[mikim]

I have a 1997 Sabre with 15hp Briggs ....did have a 38" deck. The starter is refusing to turn it over. I replaced the starter and when that didn't work I took it back where I got it to tell them they were no help. The tech there told me there is a compression release valve somewhere on it -- like on a chainsaw -- to get the thing started and that may be my problem. Anybody have a clue you can give me? It's old and I don't want to spend any money on it. I'm trying to get it to run as a run-around with a small trailer so my grandson has his very own "tractor" at the country place. (mowing deck is no longer with us)

 

[Stimw]

First, the guy dosen't know didley about that engine! The compresson release he speaks of is accually one of two things. Some engines have an arm on the camshaft that at very low speed releases the compression. Others have a special grind on the camshaft that releases the compression at cranking speed. Once up to running speed the engine bypasses this function.
My guess is that you have gas in the cylinder and it is hydraulicing. I've worked on some of those Briggs that if the carb float sticks it lets gas go right into the cylinder. Remove the spark plug and see if it will turn over. DON'T Start it. Change the oil first because it will have gas in it.

 

[mikim]

I did remove the spark plug -- and the motor spins like crazy and it spits gas out at what I assume to be a proper interval--which gave me the idea that he had a better understanding of that release than I did ... which should give you some idea of where I'm at .. .. completely in the dark. ....and lost.....Is there something else I can check? I did change the oil.

 

[Mith]

Check the valve clearances. They might not be opening properly.

Are you saying that gas spits out the spark pulg hole when you spin it over without the plug in?
If it does, check that the needle is shutting the fuel off properly in the carb bowl.

Have you checked your battery is OK, might be getting a bit old and low on power

 

[mikim]

Are you saying that gas spits out the spark pulg hole when you spin it over without the plug in? yeah ...it shouldn't? ... maybe then what I got here is just a carb problem and not a compression valve problem at all? Guess I need to pull it off and spray the devil out of it with cleaner. beyond that it'll have to go to the shop. arrgh .... didn't want to have to spend any thing more on it. Wife wants me to toss it.. I want it for the grandson's first motor --

 

[Mith]

There shouldnt be enough fuel in the combustion chamber to throw gas out the spark plug hole.
Take the bowl off the bottom of the carb, and disassemble the float/needle valve. Clean off the needle valve (wipe it off) and reassemble.
Let the cylinder dry out, and you should be good to go.

No money involved, no cleaner involved.

You could turn the fuel off (if there is a shutoff, if not put visegrips on the fuel hose) and let the cylinder dry out. Then tryt and spin it over with the spark plug in. With the cylinder dry it will probably turn over OK. Then you;ll know its a fuel issue.

 

[mikim]

Thanks guys .... now I have a POA ...and if I do end up taking it in to the shop -- I'll at least be able to give them a place to start. Course it'll be a month before I get back to the country place where it's at ... but still ..thanks so much.