is it broke or not?

[serisdaddy]

I just bought a 88 thunder craft with a 4.3L omc cobra. It runs great sitting still but going it sputters and doesnt seem to be geting full throttle and the boat fills with water. The pump keeps it under control for the most part but not really. If the pump is off it would probably sink:'( Anyway there are two rubber boots on my outdrive. The top one seems in good shape no dry rot or anything but the lower one has holes all along it. I put my finger in there and there is nothing going through it. I was told that the holes were worn spots but they are perfectly uniform as if placed there on purpose...is it broke and need to be replaced or is it how its supposed to be? And what would cause it to sputter I can only go between 25-35mph at about 25hundred rpms. My oil pressure it at 40 unless it is full throttle then shoots to 80-90 and I have messed with the trim and it doesnt really help.

 

[Boatin Bob]

Re: is it broke or not?

The rubber boots you are referring to are the drive and exhaust bellows. The upper one is the drive where the drive shaft goes through and is the most important. If it leaks besides possibly sinking your boat the u-joints and gimbal bearing will be destroyed. The lower one is the exhaust and aftermarket ones were designed/built with slots along the bottom so don't worry about that one, it could actually fall off and not really cause you any problems except the exhaust won't be directed out through the prop anymore. Since you just got it I would recommend doing a full tune up plugs, points, wires, cap, fuel filters, clean the flame arrestor and set the dwell and timing as per spec. Are you saying the boat only fills with water while the engine is running or while the boat is moving, or does it take on water all the time?

 

[serisdaddy]

Re: is it broke or not?

ok thanks atleast I know its not actually broke...it takes on water while sitting still I think because yesterday when I first put it in the water my wife watched the engine compartment and it was ok for a min. or two then she said she could hear it. As I drove the boat out she kept looking for water and said it was fine. Then I stopped and we all jumped in for about 20 min.and when we got back in it was in the storage area on the floor between the driver/passenger seats

 

[marunr]

Re: is it broke or not?

Re-read Boatin Bob's post. You most likely have a leak in the drive bellows. It IS broke and you should have it checked out asap or you will be broke too if it's not too late already. Water in the drive is an expensive problem!

 

[serisdaddy]

Re: is it broke or not?

youre right and I know that I was just saying that atleast I know it is supposed to have holes. I have a small crack near the drain plug that has silicone in it so I am going to fiberglass that and see how that works. Ive checked the drive boot and it is in good condition I dont think that is the problem but if it is, is there anyway to check oil or something to see if there is water anywhere it shouldnt be?

 

[marunr]

Re: is it broke or not?

You can check the dip stick on the top of the drive to see if it's too full, but that may not tell you anything. You should probably drain the drive oil and see if it has water in it. If it's new to you, you should probably do that anyway. Do you have a manual? You need to get one to re-fill the drive properly.

You need to pull the outdrive to check the drive bellows for water. You really can't see everything with it on. You will need to buy a manual because having one is a must for a boat owner. Many things must be done in a particular way or serious damage can result.

Here is a post that includes a link to the original manuals.
http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1136387

You should also read this if you haven't yet. (It seems a little daunting but take your time, print it out as well as all the links and it will really help you understand your outdrive)

http://www.hastings.org/~stuart/cobra/

You'll have to copy and paste the link. I don't know how to correct what's happening with my computer...and I can't make the search engine on this site work at all anymore!

 

[Boatin Bob]

Re: is it broke or not?

Agree 100% with marunr....just because the exhaust bellows is OK doesn't mean the drive bellows is. Very common for water to come in there especially if the drive is tilted up, sometimes you can have a hole that only leaks when the drive is up and the bellows is expanded, when you lower it the bellows compresses and stops or slows the leak. Here is the link that marunr was trying to give you Stuart's OMC Site It's very informative. Can't say get a manual enough times, either aftermarket or watch eBay for original OMC factory manual. Get the leak fixed, it may be small now but until you know the cause it could get worse and your pump could quit! Don't mean to scare you but don't want you to get into an unfortunate preventable situation either.

 

[Limited-Time]

Re: is it broke or not?

serisdaddy......ya got water leaking into your boat from an unknown source at what sounds like an alarming rate. Yes something is broke or at least cracked or split. You need to find out where the water is ingressing from, and correct the problem. Sounds as if your pump or battery dies as sea your sunk..........scary thought