Need new engine

[reichstall]

not sure on this motor but i do know some equipment i work on if it has any electronic stuff on it may short out when she heats up wont start than it cools down and the circle starts again. these are a terriable promblem to find. almost as bad as we had a guy throw a wrapper from his cig pack in fuel tank it would float around get sucked up against pick kill machine than after i bit fall off and float around again.Not saying this is the deal but i see on my conquest the control box is right there at steering and so it is feasable

[drslyr4]

So an update on this Kolher M18. I cleaned up all of the electrical connectors, ran some sea foam down the throat of the carb. Someone suggested the heads might be full of carbon. It does seem to start better now. I will be doing a compression test next because there seems to be blow by coming out of the dipstick tube. I'm guessing thats not a good sign.

[Frymechanic]

So an update on this Kolher M18. I cleaned up all of the electrical connectors, ran some sea foam down the throat of the carb. Someone suggested the heads might be full of carbon. It does seem to start better now. I will be doing a compression test next because there seems to be blow by coming out of the dipstick tube. I'm guessing thats not a good sign.

Ok, I know you have lots of suggestions to check out but i have a question that may narrow down your search for the problem. When you got the motor back from the shop, did it perform exactly the same each time you got it back? If it did and the compression is good then i would check timing. I know it sounds silly, but attach a timing light if you have one and with the flywheel cover off make sure its firing inside the bracket marks on the flywheel. I'm not 100 percent positive on that engine but there should be an adjustment for the magneto to put it tighter to the flywheel and sometimes a slight timing adjustment. If not then the breaker points should have one. Also clean and inspect the magneto tips to make sure they are free of rust and debris.
If it did perform differently then you might have excessive carbon in the cylinder and valves. I would pull the head and clean the carbon out, clean the valves and install a new head gasket. Hope that helps, and look forward to hearing updates.

[drslyr4]

Did a compression check both cylinders are at 100psi. I was surprized at that. Cleaned the plugs up added some seafoam to the tank, put new new air filter, and changed the oil. Fired right up in the shop and I took it for a spin. Ran real good. I didn't check the timing though, but since its not pinging or misfiring that would most likley mean its on. I think I will leave it outside and see if the problem comes back. I am thinking the heads were carboned up. Thats why I was using seafoam down through the carb. I have used this in the past to clean up interal engine parts and have had good luck. Thanks for everyone help.

[Frymechanic]

Did a compression check both cylinders are at 100psi. I was surprized at that. Cleaned the plugs up added some seafoam to the tank, put new new air filter, and changed the oil. Fired right up in the shop and I took it for a spin. Ran real good. I didn't check the timing though, but since its not pinging or misfiring that would most likley mean its on. I think I will leave it outside and see if the problem comes back. I am thinking the heads were carboned up. Thats why I was using seafoam down through the carb. I have used this in the past to clean up interal engine parts and have had good luck. Thanks for everyone help.

Good, glad its working out for you. Pining or misfiring is not necessarily an indicator of timing being on or not. Still worth a check if its still low on power or if it hasn't been checked in a long time.