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115HP Inline 6 1988 new cylinder cover

SpikeJ

SpikeJ

New member
I order a new cylinder cover (old cover had two stripped spark plug holes) from Boats.net and the cover has tapered not tapped oversized holes for the spark plugs and the top plug opening intersects the temperature switch. What do I need to do to get tapped openings? Is their a part or piece that I am missing or could they have sent the wrong part.. If they were smaller than the plug I could tap the openings but these a quite a bit larger. Any one have any suggestions?:confused:
 
Both of my 150 inlines are from the 70's and the covers are not threaded . On mine I can take the cover off and re-install the plugs . Maybe they changed something in the late 80's .
 
SpikeJ said:
I order a new cylinder cover (old cover had two stripped spark plug holes) from Boats.net and the cover has tapered not tapped oversized holes for the spark plugs and the top plug opening intersects the temperature switch. What do I need to do to get tapped openings? Is their a part or piece that I am missing or could they have sent the wrong part.. If they were smaller than the plug I could tap the openings but these a quite a bit larger. Any one have any suggestions?:confused:
Click to expand...

The "head" and spark plug holes are part of the block. You bought a water jacklet cover. If you screwed up the threads then you need to heli-coil it or use thread certs.
 
xsive said:
The "head" and spark plug holes are part of the block. You bought a water jacklet cover. If you screwed up the threads then you need to heli-coil it or use thread certs.
Click to expand...


What he said, if the cylinder head is stripped out where the spark plugs thread in, take it off and put some heli-coils in, should be able to buy a kit pretty cheap, and its pretty easy to do.
 
Looks like the heli coil has been done once already on one of the tappings. I'm not sure that it can be taken out and done again. The New cover itself looks to be the right cover. I guess what I don't understand is how would this new cover be used? If their were no holes drilled at the spark plug locations I would get that. You would have to drill and tap the holes but the holes on this new cover are bigger than the spark plugs so I would need to "fill it in?" Are their thread certs that would work? The more interesting question would be the #1 Cylinder where the spark plug hole and temp sensor hole are 1 hole that looks like a figure 8. What or how is the new Cylinder cover preped for use? If one had to use a new cover how would you go about it? My thought is that the cover was preped for something other than what I need. I purchased it online and the company does not have any idea. Has any one been through this?
 
The plugs thread into the cylinders and not the cover . So that cover will not have threads . It bolts to the motor and the plugs go through and thread into the block . Look at this picture . I removed the exhaust cover and the cover where the spark plugs go were leaking water so I pulled the power head and installed new gaskets . The spark plugs are installed and the cover was off .

untitled.jpg
 
The spark plug whole are part of the block not the cover. If it has been heli coiled and that pulled out what you need is a product Merc sold called a Keensert, it was sold as a kit with the drill tool and tap, its an aluminum insert with locking devices and a lead seal, kinda nice the way they did it. I have them if you can't find it, I'd post a pic, but ya can't
 
Thanks everyone, now I get it, the plug passes through the cover and threads into the block.:o For the previous repaired hole any recomendations on what is best? I have looked at keencert and Time-sert. the Time-cert is a bit pricey for the tool kit? Any one know where one can be barrowed. The keencert seems to use standard tools. In either case it seems best to open up the block for access to both sides of the repair but that is a job I am not intereted in. Can it be done successfully with out that? Thanks all again.
 
I'd let ya use the Keenserts if you know someone who has done it, you need a little experience to drill the hole
 
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