Mariner 350 Exhaust leak

[SanJuanDreamer]

I have 98 Mainer 350 and I found water is leaking in through the screws of the exhaust seal.
Where the exhaust matches to the hull, there are 5 though-hull nut and bolts connecting the seal to the hull.
It seems a screws at the bottom are leaking.

Just wondering if any of you ran in to this issue and what did you do?
Plan A is remove the bottom screws.
Find a way to gently lift the rubber seal from the hull and squirt 5200 between the hull and exhaust seal, then replace screws.

Plan B disconnect the exhaust seal from the muffler, then remove the muffler.
Remove the exhaust seal from the hull.
Remove all that 5200 and clean up area and reset it.

If you have a Mariner 350, you know there is barley room in the engine compartment, removing the exhaust seal without removing the muffler can lead to a problem if it doesn’t go as plan.

[mjk1040]

Plan B is ur best bet, and do both exhaust. Mike

[feeez]

I know this is a big ask but some pics of this process would be great to see.

Thanks and Cheers
Fraser

[SanJuanDreamer]

Just thought of Plan C...
Remove the 5 screws, remove as much 5200 as possible and use a jack to push the muffle towards the exhaust outlet.
This setup should push the exhaust outlet out from the hull just enough to get access to the repair area.

[bud37]

Seems to me you might want to careful prying with a lot of force.....if the sealant used by Carver was 5200 it will be extremely difficult to separate the parts and some of the parts could be fibreglass or plastic. I can't say this with any certainty but I just have this mental image of a cracked part leaking worse after you are done.....

[bud37]

Actually a question....why not just remove and reseal the offending screws and nuts and call it a day.....there should be no coring below the water line I am led to believe.......

[SanJuanDreamer]

That's Plan A...which I'm not opposed too, just want the best fix.
I know some good boat mechanics, I'm going to send pictures with an explanation this coming Sunday, see where it goes from there...

[TonyC]

We have the same boat but can't recall about the same motors. You are correct that there is not a lot of space to work in. Consequently, at 6'2", I would be inclined to complete the job as reasonably as possible within acceptable limits.

Our boats are coming on 20 years old. During this time, mechanical systems become "comfortable" with their configuration. My concern about your Plan C is that the jacking to move the exhaust, while it may work as you want, could cause undue stress somewhere else in the system creating a new problem. Therefore, I'd consider as a last resort.

Your Plans A and B are basically the same but instead of working on a single screw, your are maintaining all of them. Back to my first statement, there is not a lot of room to work in. Additionally, the amount of water that passes through the exhaust is more of a stream where the lower screws are most exposed to the effects of the water and more likely to leak. Considering the working space and the likelihood that only the lower screws may have a problem, I'd be inclined to make repairs to those that are and likely to leak ... Plan A.

I'd definitely check the other side for signs of seeping or leaking and make similar repairs. Next weekend I'm tackling our starboard rudder stuffing box as it was leaking this past Summer. While the port box was dry, I'm replacing the flax also.

Let us know how the job goes!

Tony

[SanJuanDreamer]

Here are some pictures of the problem......

[bud37]

Well after seeing the pic I think you might have to bite the bullet and take it all apart and repair properly..in the long run it would be best, when you get the muffler out of there there will be a lot more room, just don't get a leg cramp ......interesting the sealant on the outside of the boat is not stained but on the inside it appears to have a rusty looking stain from more area than just the fasteners.....