upper exhaust ports under water

mausili · Sep 28, 2011

i have an 88' sportcraft 172 fisherman with 1.6 seadrive. when motor is trimmed all the way down upper exhaust ports r under water. how do i get them out. i wouldnt imagine this boat was sold new this way, could there be water hiding in boat somewhere i cant find, or or is it what i read in other post that some or most of the seadrives where installed to low. in which that puts my self bailing holes under water also. water comes in with 2 people at the stern not moving. has anybody seen this problem or have ideas. the exhaust being under water is adding pressure causing motor to only idle at 600 rpm i think it is also causing planing problems. was also wondering if it would hurt to invest in smart tabs. thanx everyone.

mausili · Sep 28, 2011

Re: upper exhaust ports under water

now im not sure about it being installed to low for the cavitation plate is pretty even with bottom of hull when paralell.

mausili · Sep 30, 2011

Re: upper exhaust ports under water

so i found water soaked foam in hull. will it dry out if i can get air to it or does it need to come out, and should i put more back in.

Solittle · Sep 30, 2011

Re: upper exhaust ports under water

Unfortunately you have a combination that could only be worse if the rig were sitting at the bottom. Actually it would be better if it were sitting on the bottom if you have insurance.

The OMC Sea Drives cannot be raised on the transom- - well they can but it is a huge deal - - you have to completely remove the entire assembly, plug existing holes in the transom and relocate at the correct level. The Sea Drives were a bad design. I know as I have a pair of 1987s. Mine sit low but no where as low as you describe for yours.

Even if you did that it would not solve the problem of a water logged hull which is the real problem. No matter what you do the water will not dry out. You could, of course, pull up the floor and replace all of the waterlogged foam. Even if that is what you want to do you most likely will find that your stringers and perhaps transom are rotten.

My suggestion is to part it out and don't expect to get much for it due to the above. Above all please do not try to sell it unless you fully disclose the problems to any prospective buyers.

Sorry - -

mausili · Sep 30, 2011

Re: upper exhaust ports under water

transom is good shape foam is on outside of stringers. from what i can see from stringers on bilge side is fiberglass what r my chances the foam side is. it looks to me the boat is in two pieces dont think it would be hard to lift floor. i am now designing headers for upper exhaust should be interesting.

mausili · Sep 30, 2011

Re: upper exhaust ports under water

forgot to mention just bought this boat 2 months ago wife is going to kill me. by the way thank you solittle for comment i didnt think they would dry out.

metriccrescentwrench · Sep 30, 2011

Re: upper exhaust ports under water

mausili said:
transom is good shape...

That's doubtful given the condition of the rest of the boat. The only way to tell for sure is to take several core samples (drill halfway into the tramsom from the inside). If it's all good the holes can be sealed and no harm done, if the wood is wet then at least you know the extent of your problems.

mausili · Oct 1, 2011

Re: upper exhaust ports under water

i changed transducer and it was dry there but will take your advice and check different spots to make sure. will post back with find thanks

Haffiman · Oct 1, 2011

Re: upper exhaust ports under water

It is most definitely installed too low.
Your anti ventilation plate should probably be 2++" above bottom, depending on the speed you get. Due to the transom off-set, Sea Drives does not follow the normal outboard std, but more of Jack-Plate/Bracket. The older 1.6 had shim-washers to adjust the down trim stop, and they may have been missed out
The Sea Drives were great when correctly installed!!
Had a few that broke down for customers, removed the engine part, used the SD bracket and modified, and hooked on XL engines in most cases.

mausili · Oct 1, 2011

Re: upper exhaust ports under water

haffiman r u saying the motor could be trimmed to far down when talking about washers, if so where would they be. also i would say anti ventilation plate is right at or slightly above bottom at paralell. what angle should motor be at when trimmed all the way down?

Haffiman · Oct 1, 2011

Re: upper exhaust ports under water

Unfortunately no online parts catalog, but look at the stopper for the tilt cylinder. It is a 'block' attached with two screws. It used to be available 'spacers' to put under that block.
But why trim it all the way down when idling?

mausili · Oct 1, 2011

Re: upper exhaust ports under water

thats what i was thinking. i was planning on installing smart tabs to get me up quicker so ports wouldnt be under water that long, it takes a while to plane with extra weight and added pressure on the exhuast it takes about 50 to 100 yards before motor turns up and starts planing. then keep trimmed up while idling and docking. i have a prototype of headers to route exhaust up at an angle and out of water plan on trying out tomarrow.

Haffiman · Oct 1, 2011

Re: upper exhaust ports under water

Do the following:
Start with motor trimmed with exhaust ports above water.
Give full power, wait 3-5 seconds (as soon as engine starts reving up) and then trim down.

mausili · Oct 2, 2011

Re: upper exhaust ports under water

i did exactly that today worked great even pulling an adult tuber with family in boat.

boobie · Oct 3, 2011

Re: upper exhaust ports under water

When the seadrives first came out there were a lot of boat manufactures that installed them on the wrong boats that didn't have enough floatation in the stern of the boat. Therefore they became submarines. I've seen seadrives on the proper boats perform very well.

mausili · Oct 6, 2011

Re: upper exhaust ports under water

crowley has a parts catalog it looks like a thrust pad spacer. will check on that. is the purpose of having motor trimmed all the way down to take the force off of other components. i quess my question is. is there a crucial angle that the motor has to be in to get boat on plane. like a motor without tilt and trim u can reposition motor away from bracket with th pin.

Haffiman · Oct 6, 2011

Re: upper exhaust ports under water

The original intention was to compensate for different transom angles get a correct trim. Unfortunately the parts list will not fully load.

Solittle · Oct 7, 2011

Re: upper exhaust ports under water

Boat is a 1988 23' Wellcraft.

mausili · Oct 7, 2011

Re: upper exhaust ports under water

solittle r u trying to show me something in perticular? if just showing boat amazing what great shape those r in. I recently baught a pair of 86' 1.6s from a guy in orlando who was repowering. he sold me both motors and gave me the trailer they were in for $800. i was going to pull lower unit on original but shaft was stuck in crank. because mine is mechanical steering and one i baught r hydrolic, so i just swapped them at trim bracket and made a plate that bolts to both ears on hydrolic mount.

Solittle · Oct 8, 2011

Re: upper exhaust ports under water

Just showing how mine are mounted to the transom. When floating in the water, the water level is right below the plastic shroud below the metal pan at the base of the engine.

Thanks for the "amazing". My engines were originally a dull charcoal. I have always liked the Mercury black so about 6-7 years ago I did what you see here. My rig sits out in the Florida sun so the engines don't look quite as amazing now.

If I had deep pockets I would repower with a new single V-6 - 225/250. I haven't used it much in the past couple of years due to health issues.

upper exhaust ports under water

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