90hp Johnson blew headgaskets maybe seized

[alanR1]

I bought a boat w/ a 1982 90hp Johnson V4 outboard motor. The previous owner said it had been bored out 1 over. Both the left and right headgaskets blew after months of use. He flushed the motor extensively after replacing the gaskets. Hasn't run it since. Sat in yard for 1 year about. Looked at pistons and looked ok. Took off back plate between heads and saw lots of salt deposits. Haven't tried to start it yet but he said it may be seized! Any suggestions. Flywheel in neutral seems to be pretty stiff, haven't put a socket and breaker bar on it to try and turn it. Should I remove the powerhead and take off all electrics etc. and submerge it in mystery oil. Any suggestions are welcome.

 

[DJ]

Re: 90hp Johnson blew headgaskets maybe seized

alan,<br /><br />I would think that you could oil the cylinders down and hope for the best. You have nothing to lose.<br /><br />The rotational stiffness can also be caused by the water pump. They do not like to be turned "dry".

 

[alanR1]

Re: 90hp Johnson blew headgaskets maybe seized

Should I saturate the cylinders w/oil? If so what kind of oil is best fro that and also how long should I let it sit? I extremely appreciate your help!

 

[Solittle]

Re: 90hp Johnson blew headgaskets maybe seized

alan - The thing that struck me about your post is that the seller told you that it may be siezed. I would take that as the motor had been submerged even if it has not been. That would mean the motor might make a decent anchor and not worth saving (bearings, crankshaft, all electrical stuff, cylinder walls etc.). Submerging in Marvel Mystery oil will not help even though that is a great product. If you can by chance free it up without a lot of fuss that may be another story but at this point I would look to parting that one out and buying another.

 

[DJ]

Re: 90hp Johnson blew headgaskets maybe seized

alan,<br /><br />I would use fogging oil. It's available at most marine stores.

 

[alanR1]

Re: 90hp Johnson blew headgaskets maybe seized

I know the guy that sold it to me and I know it was not submerged. He just blew the head gaskets and got excessive saltwater in the motor. He nver turned it over after he replaced the gaskets and flushed the motor because he started to replace the floor inside the boat and didn't finish it so he had no need to start since then. I am hoping the flushing did the trick but I just wanted some suggestions. Thanks anyway.

 

[alanR1]

Re: 90hp Johnson blew headgaskets maybe seized

If I use fogging oil how do get it all over the inside of the motor?? Where should I spray it?? Is there an oil level in an outboard like this?? If so where do you put the oil in?? I know alot about motorcycles and cars but little about outboards even though they are all similar in their own way.

 

[Hooty]

Re: 90hp Johnson blew headgaskets maybe seized

Whip up a mixture of about four parts of Marvel Mystery Oil and One part of Liquid Wrench. Pull the plugs and saturate the cylinders with the stuff and let it set for a day or two. If you can, lay the engine down on the carbs. It'll loosen up.<br /><br />c/6<br /><br />Hooty

 

[alanR1]

Re: 90hp Johnson blew headgaskets maybe seized

Thanks alot Hooty!! Should I try and turn it over after that process?? How should I drain it all out, just flip it over and wait for it to stop dripping??

 

[Hooty]

Re: 90hp Johnson blew headgaskets maybe seized

Naw. After it loosens up, leave the plugs out and spin it with the starter. Stand clear though.<br />Actually, you can let the stuff set in it for a while. The Liquid Wrench will flash off and the MMO will just set there and keep it from rusting.<br /><br />c/6<br /><br />Hooty