'87 Tower of Power 115 Cyl. Cover LEAK!

[croSSed]

This engine has had this leak before. I had it repaired and it lasted a season. Just took my boat on it's maiden voyage and the leak now is so bad water is pouring out of the bottom cowl. It is leaking around the #2 plug hole. If it had been repaired before, and I go in there and replace the gasket, what's to keep it from leaking again? A second failure in less than 30 hours of running time tells me it's going to do it again if I try to repair. What to do? Thanks for any help.

TG

 

[emckelvy]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

Maybe you have a bit of erosion on the top of #2 cylinder. Or perhaps the water jacket cover itself is warped. You can check the cover with a straight edge and have it surfaced at an automotive machine shop, find a good used one (such as on eBay); or pick up a new one. Check www.mercurypartsexpress.com for part # and price.

If the cover is OK, you might try this old trick along with replacement of the gasket:

Pick up a tube of Permatex Red RTV (you don't want the stuff with copper in it); spread a thin coating of it on the sealing surface of the block (around each spark plug hole), and also on the water jacket cover where it seals to the top of each cylinder.

Spread the RTV out evenly with your finger. Don't make it real thick, as an excessive amount could squeeze out when you tighten down the cover, and cause a blockage if it were ever to break loose inside.

The RTV will fill in any voids and hopefully be a permanent fix.

Note: as a last-ditch-fix, with the cover on, thoroughly degrease the spark plug hole area and run a bead of RTV around the leaking area to seal it externally.

Be sure to give the RTV pleny of cure time before putting it to the test.

HTH, let us know how it turns out..............ed

 

[croSSed]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

Maybe you have a bit of erosion on the top of #2 cylinder. Or perhaps the water jacket cover itself is warped. You can check the cover with a straight edge and have it surfaced at an automotive machine shop, find a good used one (such as on eBay); or pick up a new one. Check www.mercurypartsexpress.com for part # and price.

If the cover is OK, you might try this old trick along with replacement of the gasket:

Pick up a tube of Permatex Red RTV (you don't want the stuff with copper in it); spread a thin coating of it on the sealing surface of the block (around each spark plug hole), and also on the water jacket cover where it seals to the top of each cylinder.

Spread the RTV out evenly with your finger. Don't make it real thick, as an excessive amount could squeeze out when you tighten down the cover, and cause a blockage if it were ever to break loose inside.

The RTV will fill in any voids and hopefully be a permanent fix.

Note: as a last-ditch-fix, with the cover on, thoroughly degrease the spark plug hole area and run a bead of RTV around the leaking area to seal it externally.

Be sure to give the RTV pleny of cure time before putting it to the test.

HTH, let us know how it turns out..............ed

Thanks for the tip. In the previous repair the shop tried to fix it by removing the cover, replacing the gasket, and running Permatex Forms-A-Gastket around the gasket. I know because I can see the stuff that had squeezed out. I'm thinking that I have a compromised sealing surface of some kind.

TG

 

[Bob_VT]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

The places around each plug are somewhat raised up as compared to the rest of the cover. Do as stated above and take special care in cleaning the surfaces throughly. It is tedios work but they have to be absolutely clean. The rtv spread with your finger on the places around the plug holes first and let it dry (about an hour or two then do all the surfaces again (old motorcycle trick) and it should hold.

 

[redjmp]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

Inspect the area around # 2 spark hole for signs of corrosion. Make sure to remove all of it and get down to bare metal. What I did was to use some jb weld on the surface. Just enough to build it out a few millimeters. Then I took a file and milled it down so that it was just slightly prouder than where the rest of the cover seals to the block. JB weld works like a charm. I then just used a regular gasket with just a little quicksilver sealing compound or you could use some permatex aviation form a gasket on the gasket.
If you have ever overheated the engine, then chances are that the cover is a little warped which is why it started to leak in the first place.

 

[Clams Canino]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

You can also use Permatex Ultra-Black on that cover gasket with good results.

-W

 

[jimmbo]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

My 84 115 leaked repeatedly from #2 plug. Installing new gasket with permatex sealer would stop the leak for about 3 weeks. A new cover and gasket, installed dry cured the problem.

 

[Texasmark]

Re: '87 Tower of Power 115 Cyl. Cover LEAK!

Lots of gasket mfgrs and service manuals say install the gasket dry. This, i'm sure is to keep the glue from diluting the function of the gasket. Course there are products especially for unique applications, such as Kopper Koat or Copper Coat (forgot, been awhile since I used it) for head gaskets. I will not install a dry head gasket.

I like wet installations because I think that most gaskets are inadequately supported to keep them from squirming and workinig out, and it is real hard for me to install a dry gasket, but sometimes that is what it takes. I have had good luck with blue and black RTV's. I usually put on a thin layer on both surfaces, let it skin over and install. After a few hours I will come back and re torque-tighten if it wants it.

If dry works, go for it.

I replaced mine after several years on an '89 and I don't remember whether I installed it wet or dry; sorry.

My real preference is groove/plate with an O-ring. But milling the grove costs money and OEM's don't like doing that.....most OEM's.

Good Luck,

Mark