Over Heat 70 Hp OMC partial rebuild No power?

Steve135

Petty Officer 1st Class
Joined
Aug 26, 2002
Messages
394
Hi, I did a pretty hot over heat on 1986 evinrude 70hp. I replaced the head, water jacket,all three exhust gaskets. Replace T-stat pressure relife valves and springs. Did some tests on power pack, stater,charging and coils all checked good.<br />Motor started right up. Ran great in driveway. but won't start in water. I was so glad to have found other people have had the same problem as me, because I thought I was going mad.I checked there results and I haven't fixed my problem yet. I have a primer and no choke solnoid.I know from this web site its the back pressure thats causing the motor not to start in the water. WhichI think means air might be getting in somewheres in the carbs? I just need to know where to go next? \<br />I was going to pull the carbs and replace gaskets back to block. I am hoping the gaskets might be toast! The head gasket was a burned mess! Compresion is 114/105/109 any help would be great!<br />Hey thanks I always leave out somthing.<br />I did finally get it started with the help of <br />wd-40. and it would run fine and restart again and again. But would stall out when place in gear either fwd or rev.???? Got it to run for about 4 seconds in gear at idle and is just died. Gave up day 3.<br />steve
 

Walker

Captain
Joined
Jun 15, 2002
Messages
3,085
Re: Over Heat 70 Hp OMC partial rebuild No power?

Stinky, check your primer and make sure its pumping gas. That's what was wrong with mine. If that doesn't work then hold your hand over the carburator throat and see if the carb sucks up a bunch of gas.
 

Steve135

Petty Officer 1st Class
Joined
Aug 26, 2002
Messages
394
Re: Over Heat 70 Hp OMC partial rebuild No power?

Hey thanks I always leave out somthing.<br />I did finally get it started with the help of <br />wd-40. and it would run fine and restart again and again. But would stall out when place in gear either fwd or rev.???? Got it to run for about 4 seconds in gear at idle and is just died. Gave up day 3.<br />steve
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Over Heat 70 Hp OMC partial rebuild No power?

I don't think this matters yet but keep in mind a 1986 70 HP (56 cid) has only one plate over the exhaust area, not 3 like the 49 cid motors. Its a completely different motor. Just something to keep in mind when ordering parts.<br /><br />Good luck!
 
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