Top Transfer port cover gasket blowing,

Chipso

Seaman Apprentice
Joined
Mar 8, 2004
Messages
31
Top Transfer port cover gasket blowing,

Hi:<br /><br />I have recently purchased a 1965 Glasspar Avalon with a 1965 Mercury, 65 HP, Merc 650, 4 cyl. Serial # 1803488. My good friend (Forrest) and I have been trying to get this motor back on the path to stay with the boat. Most boat yards I have called, don't want to bother with it, because of it's age. This is what we have done so far. We have cleaned and adjusted the points, checked out the electrical system and appears to be working OK, good spark to all four plugs etc. Rebuilt the fuel pump to each carburetor. We recently re-time the engine, although we didn't have all the proper tools, we feel we are as close as you may get? The engine sounds good and then shortly thereafter, this gasket blows. <br /><br />Our problem appears to be that the "top" <br />"Transfer Port Gasket" keeps blowing out on us, happened about 3 times so far. We have replaced it and the cover appears flat and we even cut the gasket oversized to possibly help. We haven't used any gasket cement on it and don't know if that would help.<br /><br />The bottom one seems to be OK and we haven't had any trouble with it and it appears intact.<br /><br />Any commments and thoughts as to why this is happening to the top 2 cylinders only would surely be appreciated.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,136
Re: Top Transfer port cover gasket blowing,

Re: Top Transfer port cover gasket blowing,

Chipso, I cannot say I am familar with your motor, but I have some experience with 4 and 6 cylinder Mercs in general. Is it possible that the ignition timing is too advanced such that one of the top two cylinders "backfires" into the crancase, thereby "blowing" the transfer gasket?
 

Chipso

Seaman Apprentice
Joined
Mar 8, 2004
Messages
31
Re: Top Transfer port cover gasket blowing,

Re: Top Transfer port cover gasket blowing,

Chris1956<br /><br />Thanks for your imput. Sounds reasonable, as there must just be too much pressure or backfire somewhere in the top 2 cylinders, that is causing that gasket to blow. Although,I wonder why it wouldn't blow the bottom gasket also, if the timing was off or too far advanced?
 

Chris1956

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Joined
Mar 25, 2004
Messages
28,136
Re: Top Transfer port cover gasket blowing,

Re: Top Transfer port cover gasket blowing,

Chipso, In answer to the question why doesn't it blow the bottom transfer covers. (Let me go more out on a limb) Does that motor have multiple sets of points or triggers? If so, only the timing for one of the top two cylinders may be too advanced, only causing backfire on that cylinder. Additionally the top two cylinders share a carb, maybe there is some link there.
 

Chipso

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Joined
Mar 8, 2004
Messages
31
Re: Top Transfer port cover gasket blowing,

Re: Top Transfer port cover gasket blowing,

Chris1956<br /><br />Thanks again for you ideas. There is only one set of points for the engine. we have adjusted and cleaned them and set them to factory specs. .008.<br /><br />Good point, that it might have something to do with the top carburetor possibly, as opposed to the bottom one, which could be working properly.<br /><br />We have re-cut the gasket today and used a gasket cement to put it in place. We are going to try this, as someone off the forum suggested we do that also. Thought we would give it a day to set up before we try it again.
 

Chipso

Seaman Apprentice
Joined
Mar 8, 2004
Messages
31
Re: Top Transfer port cover gasket blowing,

Re: Top Transfer port cover gasket blowing,

Hi Chris1956:<br /><br />Just wanted to let you know we took the boat out today and ran it for about 8 miles and the gasket held after cementing it down in place. Hopefully, it will stay in place. Now we're working on a possible gasoline leak somewhere. Thanks for your imput
 
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