Runs great in the driveway, not so much in the water - how not to buy a boat

[jrmarsh]

I just bought a 1963 Glastron Gulfstream with a 1989 Mercruiser V6 4.3 I/O. It ran great in the driveway and me being the *GENIUS* that I am decided to buy it without doing a sea trial, especially since the guy advertised the boat as 'TURN KEY", and hey, he seemed like a really nice guy...BIG MISTAKE.

I took it to my hometown marina in Monterey, CA and at first I couldn't even get it to run more than over 5 mph in the water without cutting out, then it wouldn't even start. I had the carburator rebuilt and replaced the coil (and found out the mechanic put a coil designed for points rather than an electronic ignition system which it had been converted to) which seemed to help it a bit to the point where around 1800-2500 rpm it starts cutting out, when I reach about 3000 it surges but still misses. I know that the original tanks were replaced with an aluminum tank but the filler cap had a bad gasket and water got into the system. Are the problems I am having symptomatic of water in the gas? I know it could be a lot of other things like the ignition, or the right coil etc. but I am trying to identify other possibilities as a process of elimination.
Any help, suggestions would be greatly appreciated.

Here is what I now know about the boat:
It was converted to an electronic ignition using the Sierra/Prestolite ignition module/distributor housing (which I just found out was taken out of a junked boat)
The gas tanks were replaced with a used aluminum tank, I know that at one point water got into the tank.
The fuel pump is new and delivering fuel properly.
The carburetor has just been rebuilt.
The NEW coil is not a marine coil and needs to be replaced but didn't change the way it ran anyway.

My main question here though is if the symptoms I am having are typical of water in the fuel.

Thanks,
James

 

[Hit It]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Water in the fuel can certainly cause the engine to bog down or surge. I would install a fuel/water separating filter if you don't already have one and see if that helps. If you do have one, change out the filter. Change out your existing fuel filter and make sure there are no obstructions. Also, check the fuel pickup in the tank and make sure its clear. These are pretty cheap things to try before really digging into the engine.

 

[StevNimrod]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

They can be. The only way to be sure is to check the relevant filters and test the fuel system - look for a how-to on that up in the stickies. Also, if water has gotten into the carb the water will likely need to be removed mechanically.

Of your list of things you now know about the boat, how do you know?

Did you check it yourself, or did someone else?

 

[jrmarsh]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Thanks guys, it does have a water-seperator/filter which we tried bypassing with no change in the symptoms. The information I got was partly from an old timer mechanic who put the motor/outdrive in it and things I have seen and done to it. I've got a (different) mechanic in my home town now who is going to do a compression test, throw in some new marine plugs and replace the coil with a proper one then take it for a sea trial. I will update this thread on the progress. In the meantime I think I am going to try and drain the bottom of the tank to see if there is any water in there and check the water separator. I'll probably just drain the entire tank and fill 'er up with fresh gas.

Just to let you know, the carburetor was rebuilt about five days ago and has about maybe 20 minutes of running time since. I did ask the mechanic if we should drain the tank before running the engine so not to foul a newly rebuilt carpuretor and he told me that he thought there wasn't much water in there and that a bottle of STP water treatment should do the trick. Now i'm not so sure I should be listening to this guy, though I tend to respect elders who have been doing a trade for some time so I gave him deference on this matter.

 

[Eric 3.7LX Alpha 1]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

the tank draws from the bottom the fuel fitting is on the top of the tank but a pickup runs down inside of it. If you can draw some fuel out of it and look at it thru a clear glass and see how it looks. The water will of coarse be at the bottom. If there is any you can drain it out to a point where the fuel looks good. You'll see water then it will get cloudy and then nice fuel, if there is water in there.

I had a problem with my deck fill for a while before I found it and delt with water in the tank for a couple of months. Real pain, but these experiences are what make us good mechanics and captains.

 

[haulnazz15]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

I'd say a complete tune-up is in order. First, syphon out all of the old gas and replace with new. Replace all fuel filters/separator filters. I don't know about a special coil for marine use, or electronic ignition for that matter, but I'd definitely check out their work. I would treat it as if you were installing the converstion yourself: meaning, bring the engine to top dead center on the compression stroke and see if the rotor corresponds to the #1 point on the distributor cap. You may also need to verify the voltage going to the distritor leads and coil to compare with what the electronic system needs. Many stock setups only supply voltage through a resistor for normal coil setups, but most electronic conversions seem to want a full 12V at all times. Also, new (correct) plugs are needed and properly gapped, and there's not really a "marine" plug.

 

[jrmarsh]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Thanks haulnazz15, what I meant by "marine plugs" was there are plugs you can get that resist corrosion better than everyday auto plugs.

Just to let everyone know, it starts and idles fine, cruises fine up until about 1800 rpms , then up to about 2500 rpms it wants to die. If I can surpass 2500 rpms it takes off, but still misses somewhat.

 

[Mahoney]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Check your mechanical advance weight and springs in the distributor under the electronic ignition plate. It sounds like that could definitely be the problem, or at the very least needs to be checked. If they rusted, you are not going to get any ignition advance around the rpms you are saying it is starting to die. Under load in the water your ignition is going to be way retarded at those rpm's and its going to do exactly what you are describing.

You can also check the ignition advance with a timing light, but since you are going to be in the distributor anyhow, check out the advance mechanism.

 

[jrmarsh]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Thanks Mahoney, I'll definitely check that. Every little bit of info helps.

 

[jrmarsh]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Ok so I pulled 800 ml from the bottom of the tank 750 of which was water.
ugh.

 

[Struc]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

At least you figured it out. Could have been a lot worse!!

 

[CheapboatKev]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

I was suggesting running an independant jerry can of new clean fuel, but I see you found the problem.

 

[jrmarsh]

Re: Runs great in the driveway, not so much in the water - how not to buy a boat

Well, I'm not out of the woods yet until I'm on the water and it's running great, but thanks for the encouragement. I pumped out another 3-4 gallons of fuel today, about half was water, it's running clear now so I think I got almost all of it. Then I hooked up an auxulliary tank with fresh gas and ran it straight to the fuel pump to run clean gas through the carb and ran the motor with the earmuffs in the driveway for about 20 minutes. I'll take it out on the water sometime this week but just to be safe (and to try an isolate the problem) I am going to bypass the main tank and use my auxilliary tank. If it runs well then I'll have a better idea of what the cause was.