140hp johnson wont go fast enough to plane

keithy

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racerone

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What colour is the stripe on the orange wires ? Are both top coils the blue stripe ?
 

keithy

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Took it out, got up to speed and planed out everything was good for about 5 minutes. Then I got a loud continuous beep. I shut it off and let it a minute. When I turned the key it without starting it beeped again. After a couple minutes it stopped so I went to take off again. This time the problem was back. Ended taking the cowling off and one of the cylinders is flooded, also one side hotter than the other.
 

Bosunsmate

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flooded with water or fuel?
One side often hotter than the other, what matters is how hot and by how much?
 

keithy

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Flooded with fuel. I cleaned the carbs and ran seafood through it when I got home. It wasn't extremely hot, still was able to touch it. I'll try again tomorrow with a separate tank with seafoam.
 

Bosunsmate

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You really need to check the thermostat for each head and the poppet valves if it has them
 

Faztbullet

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Peeing does not mean its cooling on a OMC, also that engine has water valve on throttle. The heads at idle will run really hot to the touch on these models. Replace t-stat inside of poppet and replace gasket as these t-stat have a tendency to stick open and the gasket screws onto poppet...
 

64osby

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Peeing does not mean its cooling on a OMC, also that engine has water valve on throttle. The heads at idle will run really hot to the touch on these models. Replace t-stat inside of poppet and replace gasket as these t-stat have a tendency to stick open and the gasket screws onto poppet...


Wouldn't sticking open allow it to cool better, or not get up to proper running temp?

Check the whole pump over, a new impeller might only be part of the issue. Also sounds like you dropped spark on one cylinder?
 
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keithy

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Well I didn't have new parts yet, but I did find a piece of plastic stopped up behind a thermostat. Took down the lower and found the plastic was from the cover to the water pump. The metal cup inside had rotated a bit and sliced off some of the plastic. Impeller looked good though. Put it all back together and will try again tomorrow. Only problem I had today was overheating.
 

Bosunsmate

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Wouldn't sticking open allow it to cool better, or not get up to proper running temp?

Check the whole pump over, a new impeller might only be part of the issue. Also sounds like you dropped spark on one cylinder?
i think that means that the system cant get to proper pressure so the water doesnt hang around long enough on the surfaces to transfer away heat, well ive read something like that many times on here
 

keithy

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Mar 2, 2015
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Success. Took the boat out after all that and it's running great.

Final verdict: one ignition coil needed replaced, carb needed a lot of cleaning, something got lodged in behind the thermostat, and the impeller cup needed to be fixed.

Thanks everyone for your help.
 
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