K@B Marine 11cc

[rosecrafts]

I have 11cc that is stamped 0003700. It runs great when water is not connected when bench testing, but when it stops ,water gets into the cylinder.It locks up. I clear it out and it will run. I pulled the cooling head and the button is slightly dirty but there is no shim. Should I replace the button or clean it and put in a shim? OR does it need a shim? If a shim is needed do I get one listed for the 5100 .67???? Is this motor the same as a 5100 .67? I need help Gary

[lh7018]

You need to find out how water is getting into the cylinder. The reason it locks up when there is water in the cylinder is because a liquid is not compressible and that's what your trying to do by turning the motor over with water inside. Forcing it with a wrench or an electric starter will only lead to internal damage. The need for a head shim is dependent on the head clearance. This needs to be measured and set and is covered in the FAQ. It may or may not need a shim or shims depending on the outcome of the measurements you take. You should set the clearance to the range that is recommended. Too much or too little will cause low power, burnt plugs, overheating, detonation or other troubles. It is really quite simple to set the clearance - the FAQ explains it with pictures. Even if your measurements show that no shim is needed the head button still should seal the cylinder to prevent water from coming in (and compression from getting out). I've run several engines this way and it is normal.
Try to avoid running the engine on the bench without a load or cooling. Runnning like that tells you nothing other than the engine will run. Besides risking damage to the engine from an over rev, the needle settings you do there (on the bench) will be useless when you try and run the boat in the water; the engine will be under load and a loaded engine needs fuel - much more than required on the bench. Trying to run the engine in the water with bench needle settings will cause the engine to most likely die in a few feet. If it continues to run it will be too lean - don't forget fuel contains the oil, it will run hot, burn plugs, have no power, etc. and the list goes on. Rich boats don't die out, lean ones do. This sounds much more complicated than it really is, it's quite simple. Let us know if you need more help, or of the outcome.