78 gulfstream omc won't turn over

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: 78 gulfstream omc won't turn over

In '78 I believe your OD is the hydro-mechanical drive. As such it probably has the three wire tilt motor. If it is original I think you will find it to be quite a mess inside. All of those motors were prone to getting water and oil from the gearbox up inside them. This is not to mention likely brush wear.

They say that once you get oil in the armature and in the stator that they will never develop sufficient torque again. However I have had luck cleaning them up including cleaning the commutator. (including re-scribing the grooves in them). If you do end up getting a new motor, do not go cheap. Cheap motor replacements are notorious for not have sufficient torque right out of the box.
 

jhcon65

Cadet
Joined
May 25, 2011
Messages
21
Re: 78 gulfstream omc won't turn over

Thank you ... It has a two wire connection presto lite brand motor . I removed The tilt motor and found that the commutator connection wiring was loose ... It actually came separated from the rest of the body of the motor .. So I can figure that that is why it would lower just fine , but not... bad connection , most likely worn out motor ... It was kinda slow before . So after boring you all with my hundreds of updates . I will replace the slave , and tilt and should be ok ... What is good brand of replacement tilt motor ? I don't want to have that problem again ...
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: 78 gulfstream omc won't turn over

....What is good brand of replacement tilt motor ? I don't want to have that problem again ...

Prestolite! And you will have some problem again as it is the nature of the beast.
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: 78 gulfstream omc won't turn over

Is it worth rebuilding ?

What? If you mean the tilt motor, I would certainly give it a try considering the cost of a new one. My tilt motor is now 37 years old. I never had any wires come loose but it had gotten pretty groaty inside. I've cleaned it up, treated the commutator and done a few other little tricks to keep it dry inside and it just keeps ticking along.
 

jhcon65

Cadet
Joined
May 25, 2011
Messages
21
Re: 78 gulfstream omc won't turn over

Well , I finally got around to working on the boat .... Thought that I had it figured out , trying to test the slave solenoid by myself was fun . No helper available .. So I replaced the slave , still nothing ..... AAAAARRRRG !! Reverted back to the post about ignition , testing and procedures ... Eliminating all that could be ... Finally found the prob , ...... Wiring , a bad connection inside of a factory splice , by accident I pulled on the ignition switch wire at the slave solenoid when I did this I had , had my test light propped on the cover so I could see it from the front of the boat And that did it . So now to open the splice , run a new wire ... No splices ... This time ... Thank s So much for all of your help ....
 
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