I have a 1977 Evinrude 70 hp. I recently rebuilt the carbs, flushed fuel line + tank, performed sync and Link, replaced spark plugs, replaced water pump and lower unit oil. The motor runs fine at idle, high speed and in forward/reverse on flush attachment. The motor runs fine in idle in the water. The motor stalls when put in gear in the water. The compression in the third cylinder is low (65 psi). The lower unit does not appear to be in any kind of a bind. Do you have any further suggestions for resolving this problem.
The compression on #3 is the clincher. You might try doing a decarb and see if it comes up. Until then, I believe you will have problems with running the motor. Need to get that straightened out before you can move forward with other repairs...
you can do a decarb and see it helps, or you can go ahead and pull the head, could be a simple as a head gasket. the decarb is going to improve the performance , but don't run it for long dragging that cylinder. you could do a lot of damage if it is a cracked ring or worse.
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I had a low cylinder over 30 lbs lower. I used the OMC spray tuner while it was running and no real improvement, I pulled the plug and put the low cylinder at TDC and flooded it with the tuner spray. I had the motor tilted up and lowered my bow to achieve an almost verticle attitude for the cylinder. I let it soak 22 hours and my low cylinder came back!!!!!! I will venture to say I am impressed and I know the original owner of my 1967 motor. This was the first time it was done.
Be sure when you are checking the compression that you have all the plugs pulled out and hold the throttle wide open.
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Do you think I can change the prop in order to help get past the initial shock of going between neutral and in gear? Right now I am using a 13-14 x 17 prop. If changing will help, what should I go to?
I am trying the power tune now and will let it soak a day or so.
"motor stalls when put in gear" - recheck your link & sync - throttle plates may be opening before spark advance - also check idle speed setting - good luck with the compression thing.
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1978 70 hp Evinrude stall when put in gear
Linear Mode
