1981 115 HP Johnson overheating

[bojango541]

Hello,

This motor starts up and runs fine, but after a couple minutes at cruising speed, an alarm thing goes off, so i'm assuning its overheating. Water is still spitting out the back though, and its not that hot when i touched it. Where should i start? Could it be the water pump. Is there something clogged in the main block of the engine, and the water isnt going all the way around to cool it? Is it the thermostat?


Thanks, Nick

 

[Dhadley]

Re: 1981 115 HP Johnson overheating

Yes, any of those things could be the problem. Verify the motor is indeed overheating with either a heat stick or a thermal gun. If you're having a cooling system issue I'd suggest starting with a water pump kit, not just the impeller. Also service the t-stats and change the deflectors. Obviously you'll change the head gaskets when doing the deflectors.

 

[bojango541]

Re: 1981 115 HP Johnson overheating

Yes, any of those things could be the problem. Verify the motor is indeed overheating with either a heat stick or a thermal gun. If you're having a cooling system issue I'd suggest starting with a water pump kit, not just the impeller. Also service the t-stats and change the deflectors. Obviously you'll change the head gaskets when doing the deflectors.

I'll do that, Just not too familiar with deflectors. What exactly are they, and where are they located. Nick

 

[Dhadley]

Re: 1981 115 HP Johnson overheating

They're in the water passages around the cylinders. Once you pull the heads you'll see them. They're actually a piece of the old 2 line fuel hose. If you look at the parts diagram they're part # 322411. You'll need 4.