1997 Muffler

I need to diagnose possible exhaust issues in my 1997 SN, GT40. My wife thinks the muffler is going as the sound of the boat seems to have changed. She also is concerned that black stains on the carpet around the engine cover might be exhaust. Here's my take.. The bilge isn't a black mess. The areas rarely cleaned around the rudder are typical dark bilgey gook, not what I would think exhaust would look like. The replacement muffler is 600 bucks. Ouch.. If it was cheap, I'd just throw one at the problem.

- can I pressure test the monster muffler that I have now? How?
- Anyone done a replacement on one of these to something with a little more... ahem... "agressive"?

Hmmmm... Now that you mention it, I have had a rich condition on occasion... It used to happen at restart after skiing half the day... cough, belch, BLACK SMOKE! Shut it off, start it back up and it ran fine til the next time. I have since narrowed this down to the temp sender. I cleaned and tightened the connection to the unit on the block and the problem went away for almost a year.

I had thought a leak also since I've been getting a fair amount of water in the bilge when skiing. But it's always cold water so I don't think it's from the muffler and as you saw in the other thread, I'm also addressing the rudder packing material.

But you bring up a VERY good point.. Not only could I inspect the baffles, but a person also could remove some if they were so inclined. Am I correct in assuming that's all that's in there is glass mat and resin?

Or.... a person could just remove the mufflers if "so inclined". Didn't you imply you wanted something more "aggressive" anyway?

LPSL. ..

Discussion and video about rebuilding Hull Hugger muffler

Fiberglass Repair on Hull Hugger Muffler


Planet Nautique Muffler Repairs

Also look for any areas on the underside of the muffler that may be worn thin from rubbing against the hull. With the muffler out, I put a flashlight inside my muffler at night and could really see the thin spots well. Replaced the rubber pads under the muffler where it was rubbing.

My engine had a loss of power due to blocked baffle. See the thread.

Bad Muffler kills performance

You'll probably be able to identify thin spots where the black has worn off and the muffler is yellow.

I had a couple of rubber support pads that slipped out of position from under the muffler. Created additional neoprene pads from HO Animal Ski binding toe pieces (not the wraps). Then used Gorilla Glue to secure the new pads. There is probably a better glue and pad material but this worked fine for me using on-hand stock.

winniskier wrote: My current conclusion is that the soot is actually composed of belt dust and engine fluids and the concerning noise from the exhaust is a figment of my imagination.   The good part is that the soot on the rug and in the bilge cleans up very easily each spring.with soap and water. That said, if I could figure out how to stop the soot, I'd die a happy man.

8122pbrainard wrote: I doubt the black stains are exhaust plus, you would notice an exhaust leak. I'd say it's black smut from your accessory belt(s). Check them for condition and tightness.

As well as alignment. Get the straight edge out!