Exhaust Problems
 

Hello all,

I have a 1979 Martini, and for some reason the exhaust tips are at water level. Every time we go to the bay, water will enter through the exhaust into the engine, and hydro-lock the boat. A few mechanics have told me I am crazy for wanting to do this, but I was thinking, couldn't I install metal flaps inside the exhaust pipe so that if water gets in through the rubber flap, the metal ones will stop it?

Any help/tips on this would be great, thanks!

A secondary flap would be a great idea as Mercruiser states if the exhaust tip is within 12" of the water line you should have internal and external flaps. I don't know your whole system but this would be a great start

It is a very weird system. There is nothing stopping the water from hitting the motor except the rubber flaps, which seem to float.....

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Both metal internal and rubber flaps. I would steer clear of those '' mechanics ''


John jr

Yes, both andThere are different external flaps that inboard ski boats use that help keep them from 'floating' up as you state.

Thank you! :)

where could i get a universal type flap from?

Hardin answered you first correctly, so give them a shot first.

If they don't have them type into your search browser "marine exhaust flappers" , click on pictures, find what you want, and then click. There should be a bazzillion to chose from.

i got one from hardin marine and it was too big... they dont have any smaller ones 410-280195 is the part number... wont fit inside a 4 inch hose... west cost offshore has one that looks like it will work... im calling first cause i dont wanna lose money on "2 day shipping" and have it come 4 days later again... and get charged a restocking fee of 15%

hjkl

ok, how far above waterline is top of riser? sposed to be something like 14 inches. I think about 6 inches of riser extension would help a lot. then you also have enough height to cut holes higher. those stern power drives are pretty nice setups. scarce. hard to get parts for-not impossible. but sturdy drives. kinda like Betamax. just cause it didn't sell doesn't mean it is junk.

Riser height is very important, but, tailpipes under water are done alot. Look at some of the Eliminator Eagle's and such...many of those have exhaust under and running some pretty crazy motors. Those would be the exhausts to look into to see how they don't drink water from being under water.

i know on the inboard ski boats the engines are mounted pretty high and the water cant go that far up hill.i dont know if your boat was built with the current exhaust but i agree that the risers need to be raised and maybe the exit holes filled in and raised up.until you can make these modifications i would concider internal and external flappers.

A little tip everyone hanging around and off the back end of that boat causes water reversion as well just sitting there especially when waves slap up against the transom.. many boats with the extended swim platforms where everyone hangs out on in party cove experience water reversion as well no matter what form of exhaust setup they have. You are lowering exhaust waterline / boat waterline. (deeper in the water). It would be wise to put riser extension blocks to raise the height. of the exhaust system.

first buy a brand new set of Salisbury exhaust flappers. when old, the hinge is looser. new ones stay closed better. then there are exhaust tips with internal flappers. I don't know of any add-on internal flappers that could be added in the middle of the hose, but if somebody designed and built one, I betcha it would sell...oh, and BUP, this isn't reversion. reversion is when engine sucks water back in while running. this is intrusion or submersion or glug glug glug.

Dangerzone, can you post a pic of your engine compartment? would give us an idea how much downhill you have in exhaust run. and I thought of an EASY cure. sell it to me!!!

there is next to no pitch on the system... along with less than a 4 inch rise on the system i think the water is easily coming in,,,i cant seem to find a in line type flapper that will fit in the system.. synamic speed marine is going to look at the boat and see what they can come up with... i know the proper fix... but i just dont want to say it out loud..

first buy brand new Salisbury flappers. then look for tips with integral flappers. then look for manifolds you can put riser extensions on or something aftermarket with tall risers. brand new external flappers stay closed. they are cheap and 5 minute install. or sell it to me!!! actually can't afford anything yet, but soon I will be shopping for a 24/7 or 22 Avanti.

Do you have a jet boat type snail system ? With your transom exhaust locatgion being so low, a standard riser located over the manifold would have a bunch of 'fall' angle.

Don't say 'sell the boat' - that is letting the machine beat you. Well, I guess that would mean you beat yourself, but we can blame the machine can't we. LOL.

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Its a 454 with a 502 cover on it...last guy that owned it....

What prize do I win ?

Um, a pack of snails - some escargot maybe? ;)

snail has a coup de ville. has a big S put on the side of the car, so when he flys by, people say look at that S car go!! now, take the snails and float test them and get manifolds you can put risers on. that motor is down deep in the bilge. I guess stern power drives are shorter than mercs, or else prop is too deep in water. you sure this is a Martini, and not a Klemm Jem?

the hull states its a b and b hull... not so sure if its a klemm jem... but i have found a solution... found a set of normal manifold(mpi i believe) then im going to have the exhaust coustom bent so i dont have to mess with the holes in the transom... im hoping that gives me at least a 12 inch rise... i did replace the rubber flappers but being there under water they do no go cause guess what they float... dynamic speed marine in chesterfeild/new haven mi is going to help me with this project as they are known for the good custom work they do... sucks im going to pay more for the exhaust than the boat but to get it done right im willing to do what ever i can... next year i want to upgrade the engine and rework some of the fiberglass to bring her back to her glory days...