older honda 100 running, but barley

[mschaeff8]

I just purchased a Honda 100 with a blue and white lid (1980's?). It starts up great. It will run at full throttle for awhile, then it will down power to a level of power that is bellow what you get from minimum throttle - though the prop continues to turn and push the boat very slowly. When it does this the engine shakes rather aggressively and it runs louder and occasionally pops like it is missing. The motor will at intermittent times return to full power for varying lengths of times (though never more then ten min. at a time). This motor may have been sitting outside for a year unused (I did use new gas). Any ideas? The help is very much appreciated.

Matt

 

[matt88]

Re: older honda 100 running, but barley

Im no expert by any means but it sounds electrical. Maybe check ignition sources. Sounds like something throwing your spark out of wack and the popping would be your carb loading up the motor when its not firing correctly. I would also check the water pump and thermostat if your motor is overheating that will also make it not run right but you said it was intermittent so that points to the ignition. Could also have more than one problem. I had one that would run ok until it started overheating and then it would lose power run rough and eventually shut off. After the motor sit for a few minutes it would start back and start the whole process over again. I fixed the overheating and have not had any trouble with the motor since except for a minor carb issue.good luck