sparks4540
Seaman
- Joined
- Feb 20, 2004
- Messages
- 50
I bought the '89 15horse force motor over the winter. It ran great for about 20 minutes and then ran on the top cylinder only. Compression test was good at 116top and 110 lower. I pulled the head to inspect the cylinders and replaced the head gasket. I also rebuilt the carb,inspected the reed plate,replaced the fuel pump and reed plate gaskets and the carb to reed plate gasket. There is no fuel squirting out the back of the carb and all the reeds look good having no gap or .005 max gap between the reed and plate. This model has a recirculating fuel system so I pulled the recirculating fuel drain valve plate off and found both screens had debris covering them. I cleaned them off and reinstalled. I pulled the exhaust plate off and inspected the ports. Nice and clean. I replaced the points and condensers with a magnatune ignition system. Both plugs have good spark. The engine fires after 1 or 2 pulls and runs great when throttle is opened. With throttle completely closed it idles at about 2000rpm in neutral. I have checked for vacuum leaks and the only time the idle slows is when i squirt around where the motor mounts to the lower unit. Is there vacuum under there??? Could the exhaust cover gasket be bad or the drain valve plate??? My buddy says to check the piston skirt...?? The engine also seems to load up if it idles for a few minutes. Both plugs look pretty dirty when I took them out. Champion L87YC gapped at .025 per Magnatune instruction. Any other ideas would be great.
