Whats the best fix for leaky big block Merc. exhaust riser gaskets? [Archive]

View Full Version : Whats the best fix for leaky big block Merc. exhaust riser gaskets?

Eriktheviking

03-13-2003, 09:20 AM

Last summer I replaced my riser gaskets twice.Once with some cheap ones made for NAPA,(which blew out) http://www.checkmate-boats.com/infopop/emoticons/icon_mad.gif,the second was a set of Quicksilver 27-863724 gaskets.They did last longer but did eventually fail. http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/zx11pissed.gif Before installation the surfaces were examined and cleaned and looked okay.This is not a saltwater boat.Got any suggestions? http://www.checkmate-boats.com/infopop/emoticons/icon_confused.gif

Eriktheviking

03-13-2003, 09:20 AM

03-13-2003, 08:08 PM

If Dr. Z doesn't answer, then you should get some input over at Scream and Fly..

1995 2100BR/1995 225 Promax/23" Tempest

BayviewRick

03-13-2003, 09:05 PM

You may need to have the surfaces machined...without seeing it, we can't be for certain, but you may have some oxidation, maybe some warping causing the problem. If it was one set, i'd say no, but two makes it questionable. It's very important that the surfaces are accurate and clean. It's not really the right way, but a hi temp sealer such as Permatex is a little more forgiving than a gasket if you do have some warpage. Rick

www.Bayviewmarinecenter.com (http://www.Bayviewmarinecenter.com)

Bill

03-13-2003, 09:11 PM

Something that needs to be mentioned here, Never put automotive accesories on a marine engine! http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/jpshakehead.gif You are asking for trouble!

vinny p.

03-13-2003, 10:19 PM

Merc. makes 2 types of gaskets for their risers. The original type was a thin gasket with print-o-seal embedded into the gasket. These gaskets really sucked, they leak all the time. The " New Design" gaskets look more like those waffle type automotive exhaust manifold gaskets. These are better. As was stated above, if the surfaces are not straight, regardless of which gaskets you use, they will never hold up. Put a straight edge across the surfaces, then measure the clearance between the straight edge and the surface with a feeler guage. This will tell you how much the parts are warped. Personally, I would throw away that junk Merc stuff and get a set of Gils'. That way, you will never have this problem again. It pays to do this now, before those Merc. manifolds cost you a motor.

Eriktheviking

03-13-2003, 11:45 PM

Bill, Maybe you misunderstood about the NAPA gaskets.They are mostly an automotive store,but NAPA also carries a large line of marine products for outboards and I/O's.Anyway, Rick and Vinny the surfaces did look decent but probably after 15 years they're a little warped.I did pick up a set of used GIL HI-TORK exhaust.I still need to get the necessary shift and oil filter brackets for them and get'em installed. You'll hear me coming then! http://www.checkmate-boats.com/infopop/emoticons/icon_biggrin.gif

vinny p.

03-15-2003, 07:37 AM

To ditch the stock Merc stuff is a good choice. It will probably save you a motor sometime!

Bill

03-15-2003, 10:36 AM

Erik, you are right, I saw NAPA and assumed automotive. I learn somthing everyday too, I did not know NAPA sells marine good, I have an account with my local one here for my business, I will ahve to check that out. Thanks!!!!!!! http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/thumb.gif

MikeW

03-21-2003, 05:13 PM

Vinnny has the right Idea. A set of Stainless Marine manifold are just the ticket. They have a by pass hose so no gasket and use a very cool "Big Truck" type clamp for the risers that work very well and allow you do turn them a bit if you don't have good tip to manifold alignment . I have a set on my Convincor, had Gils on my blower motor, Like them both. SM is less money and work just as good.