gamefisher 3hp

[falco]

I just bought a '91 3hp gamefisher for my 10' boat. It runs perfectly while it's out of the water (it's air cooled) but will "bog down" and die when you put it in the water. It will idle okay , but once you start to increase the throttle it will bog down and shut off, it doesn't matter if it's hot or cold. Once it shuts off it'll start again with just one pull and go another 200 yds or so before it shuts off again. I opened everything up expecting to find a gummed up carb, but it was surprisingly clean. I couldn't find anything restricting flow of fuel or air. It's got plenty of compression and everything turns smoothly. This is one of the models that doesn't have a muffler. The exhaust it just piped down below the water and comes out a couple inches above the prop. My question is....i know it's designed to function that way, but could the backpressure put on the exhaust by the water be causing the problem? It has a few small holes drilled in the exhaust pipe above the water level to relieve some of the pressure....if this turns out to be the problem all i'd have to do is drill a few more hole and it should run fine. Hopefully some of you guys have some experience with these motors...i'm new here, but you guys seem to have quite a bit of knowledge about boats and motors.

 

[daltonmcgill]

https://www.tinboats.net/forum/viewtopic.php?t=4585 this might help you

 

[falco]

thanks dalton, i did a search and found that thread but unfortunately that's an older model 5hp that was made by tecumseh...i have a newer model 3hp that was made by tanaka. They're actually designed quite differently.

 

[Loggerhead Mike]

check your float to make sure its adjusted right. also check your reed valves to make sure all are seated properly. you can shine a flashlight behind them to make sure they're seated. you can also pull the flywheel and make sure the magnets are strong, and theres no corrosion between it and the coil.

another good check while your motor is running, spray brake clean or a starter fluid around gaskets that may be leaking creating a vacuum.

 

[CarlF]

Sounds like either stuck floats or clogged jets in the carberator to me. Give it a good cleaning, maybe put in a carb kit and it will most likely be fine.
Check to see if there is water in the bowl as well.

 

[ben2go]

thanks dalton, i did a search and found that thread but unfortunately that's an older model 5hp that was made by tecumseh...i have a newer model 3hp that was made by tanaka. They're actually designed quite differently.

We have a winner Johnny.100% right on.The Tanka motors are more like boat motors than the Tecumseh based ones.1st check the gear lube make sure it doesn't look like chocolate milk.Next,I would look at the fuel lines.Even if you don't see a leak there maybe one.Any little bit of stray air that enters the fuel line(s) will cause the carb to loose fuel pressure.The fuel pumps on outboards are weak, to prevent them from over powering the carb float,and flooding the engine.This brings up another issue.The carb float could be set to low starving the engine while it's under load(water resistance).The next thing inline could be be weak spark plugs or the ignition timing is off.I'm sure there are other things that I am not thinking of right now.