1967 Johnson 80hp troubleshooting steps

[ahowler]

Looking for ideas here. I will explain my trouble and take any suggestions on steps to fing out the problem. Motor starts up nicely after a spray of fuel mixture sprayed in carbs. On this motor you have a little door that opens up in the front to access the carbs while the engine cover is on. So here is the first clue engine will die when you close this door. Leave it open and it runs fine. Next clue engine runs ok until you try and go full throtle, it will get going until it gets to about 1500 rpms then bogs down but slowly increases speed until it gets past 2000 rpms the wide open kicks in and the boat flys! Sounds great at wide open smooth. But back of the throtle and go below 2000 rpms and it starts all over again. Again thanks for any suggestions!

 

[yorab]

Re: 1967 Johnson 80hp troubleshooting steps

First of all, it sounds like exhaust is backing up and getting into the carbs when the door is shut. That is why the motor is suffocating when the door is shut. I believe (though I'm not 100% sure) that your motor is basically the same as mine (motor in signature). This most likely means that the doughnut seal at the water pump or the exhaust seal ring is bad. You can find an exploded view of your motor at marineengine.com, where you can find these parts. I see that you are new to the forums so I can give advice that is a bit more in depth if you need it. Or, others are always here to chime in as well. Let us know.