Re: 15 horse force fast idle
I bought this motor over this winter. I brought it home and found there was no spark to the lower cylinder. I found a hole in the plug wire and trimmed it back. Good spark now but lower cylinder still missing. It ran great for about 20 minutes then the lower cylinder quit again. Good spark but wet plug. I ran compression check and found top cyl.120psi and lower 105psi. I replaced the head gasket, fuel pump,reed plate gaskets,carb gasket and rebuilt the carb due to goop in the carb and installed a Magnatune ignition system to eliminate the points and condensers. Installed new plugs, gapped at .025 per instructions, and another compression check yielded 118 top and 112 lower. The reeds were in great shape so I left them alone. After reinstalling the engine I found there was a vacuum leak around the seal where the motor mounts to the lower unit. I added some sealent and sprayed around the mounting surface with no change in idle quality. Every time I spray around the shaft where that controls the butterfly on the carb, the idle comes down. I spray around the reed plate and the carb mounting surface with no change idle. The butterfly is closed and the advance plate under the flywheel is adjusted back. The inside of the engine is clean. I pulled the exhaust cover and it too was really clean. The engine runs great when you gas it, but it's just the idle that is too fast and not really that smooth. It seems to load up on itself and if I lean it out by turning in the idle mixture it smooths out but races more. It really seems to be a vacuum leak, but nearly all the gaskets are new. Is there vacuum where the engine mounts to the lower unit??? Hope this helps. Thanks.
