Questions about a 1972 21' Slick Craft & Engine stalling at speed

Hi, I bought a 1972 Slick Craft last summer and it's a beautiful boat, it came with new upholstered seats, and it ran like a charm. Over the beginning of the summer I had to have some wires replaced because they were brittle, I know I had the solenoid and I think the starter replaced. Around the 23rd of Aug. I was boating at Kinzua Dam where I usually do and all of the sudden it made a few banging noises as it stalled out while we were going full speed. It started right up for me and my parents and we started back towards the marina when it stalled out again, once again though it started right up no problem, we then figured out that as long as we stayed at a low speed it would run, but if we sped up to much it would stall out again. When we got back the guys at the marina said the engine was frozen but from what my dad knows of engines and even from what other mechanics have told us, if the engine was frozen it shouldn't of started up again, and especially the five or so times we had to restart it. If anyone could give me their advice on what could be wrong with it I would appreciate it.
Thanks.

 

The best advise you could get is to take the boat to a qualified mechanic, that specializes in your engine/drive combination. Have them look over the engine and drive. Your engine may have gotten hot enough to seize up, could have had a mechanical failure which seized it, lots of things could be wrong. Without considerably more information, we'd be guessing as too what is wrong.

 

You have to give us a little more information, is it petrol or diesel? carburated or injected? From what it sounds like to me your starving it of fuel, check your filters (fuel), if you have a carburetor do you have a sticky float, again without more info impossible to say, could be a loose earth wire to the distributor.

 

Its a fuel problem , the faster you go the more you use so going slowly could be coped with.

So anything to do with fuel, fuel filter, fuel breather try it without the fuel cap, fuel pump etc etc.

 

Thanks for the info so far, I know it's Petrol and it's carburated. Any more info would be appreciated, this is my first boat and it's a good boat, I would hate to see it scrapped.

 

Given you will not or probably can not offer more then it being a gas powered, carburetor boat, you clearly need to take it to a professional. A diagnosis will run about $50 and worth the effort, especially considering your boating experience and mechanical abilities.

 

Sounds and acts like old fuel - try running on a carry on six gallon can of fresh fuel.

 

I'm going with PAR take it to a mechanic.

If you want to have a go yourself here is my to do list in order.
1 Change your fuel filter
2 Change your distributor cap
3 replace your leads
4 replace your plugs
5 replace your air filter
all above are all easy to do and do not require specialty tools, are also cheap to buy and should be replaced frequently anyway.
If that doesn't work by a Carby kit, replace needles seats and jets, then look at distributor points and the coil.
If still no success find an auto electrician and get him to chase the wiring.
Good Luck

 

Don't replace anything, Jpyoda! Before changing parts on what possably could be a dead engine, preform some simple tests, though honestly considering your answers thus far, I'm not sure this is in your realm of expertise.

The first thing I would do is try to crank it. If this fails pull all the plugs and see if you can spin it manually with a breaker bar. If you can, it's not seized, so the next thing is to examine the condition of the plugs, which will tell you how the engine was running when it was shut down last. If you can't spin the engine manually, then you've got a seized engine and it may be trash or possably repairable, but it has to be disassembled to find out. During disassemble, you'll find out why it locked up and usually the resulting damage, will tell you if the engine is worth rebuilding or using as a mooring anchor.

 

Thanks for the info everyone, it's very helpful.

 

You are correct in what you say.If you do decide to take it to a mechanic and of course that is the best from your knowledge but not the mechanic above please.

Frozen means seized, --that means it will nor start or crank even.

I dread to think what this mechanic had in mind doing to you.

 

Frosty, I suspect it locked up after it cooled down or as it's last gasp at the recovery ramp. It was probably getting "tight" and it stalled a few times, offering a warning to a hopefully listening owner, but alas the smells, noises, vibrations, drop in RPM, decreasing preformance and oil pressure, rising water temperatures also weren't heeded, so the inevitable might have occurred, just as or just after they reached the launch ramp. Of course this is pure speculation, as the boat may not have had any gauges except the go fast dial, noises and smells are blown aft, off the boat, etc. Who knows, though any reasonably qualified person can check to see if it's locked up easy enough.

 

a tip for you and cost bugger all to check
take off the oil filter, split it open with a hacksaw and open up the paper and READ what you see, aluminium for piston seize( a bad one) and bronze for bearings
I was a heavy equipement mechanice once and when an engine semi or seized, this is the first place we looked
If there is nothing, do a compression check and , oh there are so many threads on this
But when I buy a truck or boat, I insist upon a filter read

 

Has he got no temperature guages on this boat then?

Exhaust tone louder?

 

Apologies, when you said the motor was frozen, i thought you were talking about temperature of the motor. If your motor is seized its a different story altogether.
Take out all the plugs as suggested, disconnect the leads and crank the motor, If the motor turns and has compression in each chamber all good to there, If not you've done some damage inside seek a mechanics advice. Smell the oil through the filler cap, if it smells burnt you have other problems internally, again seek a mechanics advice.
If the motor turns and you have compression and the oil smells Ok, the motor is not seized. Do a Compression test, and the follow the steps.