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View Full Version : Exhaust muffler leak and replacement S&S 81/82


harv559
08-08-2006, 12:57 PM
I need advice and expertise please!

I have a late 1981 Dlx (1982 features) Master Craft, 351 Ford, PCM. While I was investigating leaking water into the bilge I discovered:

It appears have a leak in the exhaust muffler (Drivers side).

Facts:
1. It leaks water into that side of the bilge, although it seems it isn’t really hot water. I do not get the water into the bilge while I run the boat (with water hose attached) when on the trailer. ( Does it only leak when the flange has back pressure from the lake water?)

2. I definitely see exhaust fumes inside the boat at the back of the boat where the floor boards end under/near the gas tank. I have the original fiberglass encased mufflers. ( Note: I see these fumes when running on trailer ( via a flashlight), and do smell them when on the lake.) Because I have little kids that sit back there I need to fix this!

Questions:
A. Do I need to take up the floor boards to get out the muffler or can I pull/push it out through the flange holes? ALSO, it looks like I would have to take out the fuel tank to get to the 4 or 5 hose clamps in the rear which hold the hose to muffler, hose to tubing to flange. Is this the massive job I have ahead?

B. If I “take up” the floor boards: The board is “glassed” to the side of the boat. Is it necessary to “reglass” the new board to the side of the boat? Does it add any structural/design integrity. I thought I could just cut out the floor area necessary to get to the muffler.

C. On replacing the OEM muffler: Is Skidim's (same as Overton's) part # 0911 the correct/best replacement? Can part #0912 apply (with an angle up), thus reducing the number of bends in the hose? Do I replace the OEM plastic tubing which goes through the flange opening?

D. If I am replacing one side, should I replace the other muffler also?

This is too big of a project for midsummer!

Thanks for your in advance for your expertise and advice.

LakePirate
08-08-2006, 01:21 PM
Have you found the cracks?

If so you might be able to mend them for now and take on the replacement over the winter.

ski_king
08-08-2006, 01:33 PM
I have an 82 and my mufflers are under the removable center floor board. Easy to lift. You make yours sound like the mufflers are under the outer glassed in floorboards?

My mufflers had a crack once where the exaust hose connects. Easy to take out and do a fiberglass repair to the muffler.

Post some photos of your boat, I want to see it!

mhobbs01
08-08-2006, 01:42 PM
The mufflers should be under the removable floor board just aft of the engine box. It may be different on the 81/82, but you should be able to remove the engine box, rear seat and the panel behind the rear seat. You should see 4 screws holding the panel down. I don't know about repairing them, but I imagine it's possible with the right stuff. If you wan't to replace one or both, skidim.com has them for about $130 each. As far as getting under the gas tank and reaching the hose clamps at the transom; I've wondered about that myself because my muffles are leaking as well. I think it may require removing the gas tank, but I don't think it would be too rough. It would be a good time to replace the fuel filter, check the stuffing box, etc. I'll send you my email address since we're both in Fresno.

harv559
08-08-2006, 01:53 PM
I have not found the cracks as the muffler is 90% under the floor board. So far I have only removed carpet, screws on middle/center stringer. This is when I discovered the board is glassed to the side wall.

harv559
08-08-2006, 01:59 PM
Unfortunately the mufflers are NOT under the removeable floor board attached to the engine cover. Under that section access is only to the drive shaft, steering and rudder, transom drain, and drain holes in stringers between side sub floor sections.

Bruce Carr
08-08-2006, 02:44 PM
I think you boat has the exhaust running outboard of the stringers. Later models, '83 and newer for sure, had the exhaust running inboard of the stringers.

I think you can get the mufflers out by disconnecting the mufflers at the 3" diameter hoses coming off of the exhaust risers at the engine, then removing all the screws around the exhaust flapper flanges on the outside of the boat at the transom. The mufflers should slide out aft through the transom.

Fixing the cracks is fairly easy. Get some fiberglass resin and cloth at Home Depot or your favorite auto parts store. Clean the mufflers in a large area around the crack(s) with acetone, sand with course sandpaper to roughen up the surface, clean some more with acetone. Then lay up two or three plies of the glass and resin over the crack(s) with lots of overlap onto the surrounding surface.

Its not too hard to repair and the glass repair will last forever if the surface is claen.

mhobbs01
08-08-2006, 03:10 PM
There is a West Marine on West Shaw east of the 99 (not sure if you knew, its somewhat new) if you decide you want to repair the mufflers and redo the glass on the floor. They have all the west system epoxy and fiberglass cloth you could need.

harv559
08-08-2006, 04:52 PM
I KNOW my mufflers run outboard of the center stingers. Thanks for the advice. I can't imaging that pulling or pushing the muffler with the riser hose end attached will be easy. Unfortunately, the riser hose is clamped at a point under the floor boards. Getting to the clamps at the transom under the gas tank would be impossible because only 1 arm can get in there.

The OEM mufflers seem so thick, it is hard to imagine they would crack.

harv559
08-08-2006, 04:53 PM
Luckily my brother in law is a fiber glass guru, having built a Velocity kit plane, where 80% of the build was fiberglassing!

harv559
08-08-2006, 04:56 PM
Could you see the crack really clearly upon visual inspection? Was the water leaking into boat hot? I have an 82 and my mufflers are under the removable center floor board. Easy to lift. You make yours sound like the mufflers are under the outer glassed in floorboards?

My mufflers had a crack once where the exaust hose connects. Easy to take out and do a fiberglass repair to the muffler.

Post some photos of your boat, I want to see it!