1973 Evinrude 135 hp overhauled and bogging down

mcdonkey37

Cadet
Joined
Jun 12, 2009
Messages
19
Hello,

So my engine (135 hp evinrude) is finally together and I have been breaking it in. I have been running it in a tank around 1500 rpm's. 9 gallons of gas so far. The engine will run fine and then make a poof/pop sound and bogg down to 1000 rpm's or lower and sometimes quits right after it sputters out.

Is this common for on overhaul?

I have been running it with premium gas and a mixture of 32/1. I realized the other day that the premium gas I used for 6 gallons had 10% ethonol, would that damage the engine?

A boat mechanic stated that I probably have an air leak in the gasket by the crankcase. He said with time it could seal up on its own. He recommended taking it out in the water to put a load on the motor.

Is there a sealant or something to use to stop the air leak?

sorry for all the questions, I just want to give all the background information and find what is causing the bogg down.

thanks for your help
 
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