1985 90hp Merc Stuck, tear down?

mnmfors

Petty Officer 2nd Class
Joined
Nov 18, 2001
Messages
176
Hello everyone,<br /><br />I have had this motor lying around for about 6 months waiting for me to give it a new trigger. <br /><br />Now it won't turn over. I removed the lower unit, still won't spin. (lower unit fine) I have had some PB Blaster soaking in it for about a week and a half. Still won't budge. I plan on using the wooden dowel trick I read about earlier. I am just being patient. I know I will get it freed up sooner or later. Any other suggestions to speed this up?<br /><br />I did a search on this topic. I read a couple of posts on some 9.9's with the same problem. A couple of suggestions for teardown and inspection of the bearings came up. I didn't want tear it down, but I don't want to fix this motor only to have it fail a week later. Suggestions?
 

NEECAPRS

Petty Officer 2nd Class
Joined
Jul 25, 2003
Messages
126
Re: 1985 90hp Merc Stuck, tear down?

Stay on your current approach- don't tear it down(YET!!). The pistons and rings are stuck, not the bearings. :)
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: 1985 90hp Merc Stuck, tear down?

I use a mixture of Marvel Mystery Oil and Liquid Wrench to free up stuck pistons. Three parts MMO and one part LW. Works for me.<br /><br />c/6<br />Hooty
 

mnmfors

Petty Officer 2nd Class
Joined
Nov 18, 2001
Messages
176
Re: 1985 90hp Merc Stuck, tear down?

Thanks Hooty, I will give that a shot. <br /><br />Neecaprs,<br />"Don't tear it down...yet". <br />Would you suggest removing the exhaust and intake covers to inspect?....or will a compression check do in your oppinion? I would rather not take them off if I don't have to, as I know with my luck, I will break off a bolt or two.
 

NEECAPRS

Petty Officer 2nd Class
Joined
Jul 25, 2003
Messages
126
Re: 1985 90hp Merc Stuck, tear down?

Comp. Check: Do it first to see if there are any more cylinder wall/ring problems. Don't take any more pieces off until you find some reason to. You're sure right about the bolts-- my luck too!! ;)
 

mnmfors

Petty Officer 2nd Class
Joined
Nov 18, 2001
Messages
176
Re: 1985 90hp Merc Stuck, tear down?

Awesome mix Hooty, engine is freed and has good compression!!!! (150, 160, 160, 160, 150, 150)<br /><br />Neecaprs,<br />In reference to the bearings, Should I let it soak a little while longer? Or should I assume the bearings are OK and go ahead and start on the ignition?
 

NEECAPRS

Petty Officer 2nd Class
Joined
Jul 25, 2003
Messages
126
Re: 1985 90hp Merc Stuck, tear down?

I would assume they're okay. Hard to be certain, but, the sticking of the rings doesn't promise bearing trouble. Run with extra oil on the first tank to reduce risk. :)
 

mnmfors

Petty Officer 2nd Class
Joined
Nov 18, 2001
Messages
176
Re: 1985 90hp Merc Stuck, tear down?

Thanks again Neecaprs
 
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