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-   -   Leaking Flange on CMI's (https://www.offshoreonly.com/forums/general-q/189728-leaking-flange-cmis.html)

J.B. Marshall 07-03-2008 06:51 AM

Man that sucks... what motors due you have. Did you just have work completed on them recently? Cannot be new and have 4o hrs or it would be under warranty? I would go back to who did the work on them. Just my $.02

I just put back together my port motor exhaust (header & Y pipe) after having carbon exhaust leaking from the flange. I used two gaskets and perma gasket and I hope this does the trick, I have yet to put the boat in the water to test it, hoepfully tomorow.

BillR 07-03-2008 12:58 PM

Headers have likely sprung a leak.
Older (merc) Etops are famous for that. Probably leaking right @ the flange that bolts to the head.
If so - DON'T fix them. Buy the new cool collar Etops. Then you will not have this issue again.

SAME thing happend to mine.

thirdgen327 07-03-2008 02:23 PM

well, I went to do the leakdown test and my tester was F'in up so I didnt get too. I pulled the header on that side and the primary tube for #6 was FULL of water. That primary has the orange water spots all over it and didnt look very good. 4 and 8 had some water in the primaries as well but still looked good.

Also, It appears that the flange is still leaking internally even though i couldnt see external signs while it was running.

Why would the primary have that much water in it. I am starting to think its my header now but I still have to do the leakdown tomorrow.

Thanks for the replies

BillR 07-04-2008 07:35 AM

You can hook a garden hose to the header - remove the rubber crossover and cap it- then hook the hose to inlet and turn on. Your leak should present itself.

thirdgen327 07-04-2008 08:22 AM

Thanks man, gonna do that right now. You guys have been a big help.

thirdgen327 08-12-2008 01:11 PM

I know its been a few weeks , but heres an update. It was a very small breach in the head gasket. Replaced and no more issues. Everything else checked out great.. At least its fixed and the headers are still good.. lol

Enjoy whats left of the summer.

Thanks again guys.

J.B. Marshall 08-12-2008 02:38 PM

Excellent... Glad to hear you are back out having fun. :ernaehrung004:


I am in the process of taking off my manifold and tail pipe on the Stbd side of the stbd engine to add a second gasket and some permatex to stop a leak that came about last weekend.
Had to do another one earlier in the season, they are a pain in the Azz.


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