1990 supra exaust question

[goldnut]

Hello all, I am working on a 1990 for a customer. There is a water leak around the starboard exhaust outlet. I backed the boat in the water and could hear water coming in. This boat was overheated and slightly melted the beauty rings that attach to the transom and enter the mufflers. Are these just siliconed in to seal the muffler or is the some sort of mechanical fastening on the inside. I dont want to pull the tank if it isnt necessary. Also where can I purchase the rings? Thanks Ken

[Jetlink]

www.skidim.com will most likely save you on parts that you need to source. As for the other questions that depends on the model of boat and the engine as the exhaust outlet is specific to a small block or a big block, 3 inch diameter for the small block and 4 inch for the big boy. Depending on the set up as there are so many various ways the factory or even owners after the fact did their exhaust it will be difficult to give you a finite answer. I overheated my exhaust last year and it was caused by a faulty muffler so I had to replace the muffler, the flange and all the exhaust hose as well.

[Salty87]

There are a couple variables. Pics are always helpful. Not all had mufflers. 351s are more likely to have them 454s in my limited experience.

Weird to hear water coming in although some models had the interior side of the exhaust pipes exposed and some have flooring/foam over them. Water will certainly fill the exhaust pipes when backing in and be loud enough to hear. You might try taking a pic down the inside of the transom behind the gas tank above the exhaust pipes to see if they're exposed or under flooring. If there are mufflers that aren't exposed then some of the floor will have to come up. If it has a 351 then a tank pull is probably necessary to inspect mufflers.

Do they look like this?


If these the plates need to be sealed to the transom and also a couple inches up the pipes where the exhaust pipes meet the mounting flange. It's not mechanical.