Boat will not run right...

[JaseBosto]

Everytime I've been on the water, it wasn't long till I got stressed out, and right about now I feel like sinking this boat.
Now the issue:
When I go to start the boat, it is difficult to start, cold or hot. It wouldn't run well at all. Meaning, it would idle ok, but when you try to plane off, it would lunge forward like it wanted to, then die out. After that, its very difficult to start. Most of the time it wont. I have to dump a tiny bit of gas in the carb to get her to fire up. After that, it will run but anything over idle and it dies. I have already had the carb rebuilt(and it is a thing of beauty now), replaced the fuel line, check ball valve, water separator, and fuel strainer in the carb. Fuel strainer in the tank was clean. Spark plugs, cap, rotor, coil all replaced.
No effect on the problem......! Any ideas? My chick stood by for over 4 hours today while I wrenched on this boat at the marina trying to get the problem solved. Eventually I got sick of working on it, and just putted around. I gave her a pat on the back and said thanks for hanging in there. IT was not fun, and hot as hell.

 

[HorizonblueDK]

Re: Boat will not run right...

Sounds like the only thing you haven't replaced is the distributor itself.

If the engine is from 1990, it has electronic ignition, with mechanical advance. I once had a 570 Volvo engine laying around (350 V8 GM) where the springs for the mechanical advance was broken, I wonder how the engine would have run with that.....?

I sold it to a guy who had a Thunderbolt distributor, which we installed and then performed a testrun before the sale.

Anyway, my best guess is that your problem is the distributor. Broken springs or faulty ignition module. If it is the problem, find yourself a new Delco marine distributor. They are often sold as a kit with coil, wires etc.

 

[JaseBosto]

Re: Boat will not run right...

How about a fuel pump? To give you an idea of whats happening, When I loaded it on the trailer, I could "gas it" to get it up there. It will throttle up for a few seconds before bogging down. IF I gassed it for about 2 seconds then got off it, gave it a couple seconds I could do it again.

 

[JaseBosto]

Re: Boat will not run right...

bump

 

[HorizonblueDK]

Re: Boat will not run right...

Fuel pump, maybe. I suggest you install a fuel pressure gauge on the line between the pump and the carb. I don't recall how much pressure you need, but those specs should be easy to find.

 

[Don S]

Re: Boat will not run right...

Would help if you posted the full model number or serial number of your engine so we know exactly what your working on.

 

[frantically relaxing]

Re: Boat will not run right...

When we first bought our '88 Sun Runner (in 2002) I was having similar issues. And there were several problems I found that contributed. Problem 1 was the bad power valve in the Holley, it was dumping fuel constantly. Replaced with a higher vacuum model, and wow, what a difference. But still not quite right. And since I'd never seen 74 and 76 sized jets in ANY Holley before, and because we were boating at no less than 4400' altitude, they got changed out for 69 and 72 sizes. She ran great-- for the most part... And the soot I was getting on the transom after every trip stopped. But one issue kept plaguing me, which was misfiring and such above 3000 rpm. Not always, but usually. Turned out THAT problem was caused by the distributor. Upon inspection, it appeared to me that I had way too much slop in the top of the distributor shaft, so much so that at certain times the triggers on the shaft were moving so far from the pickup coil that it wouldn't "see" the trigger(s) which would cause a no-spark. To test my theory I set the pickup coil and triggers with ZERO clearance, and hoped the triggers wouldn't saw into the pickup coil. It worked- the boat ran a ton better, but still had an occasional fit of misfiring. So I ordered up a new Mallory Unilite distributor, and pulled out the old one-- First thing I found was upper distributor gasket was half in the mounting hole, and half out. I thought, that can't be good... That caused the distributor to seat on an angle. And this caused excess pressure being forced on the lower shaft bushing. It wore the bushing out so badly that, well, check the pictures, I was able to fit a paneling nail into what should be a near-zero gap! That wear caused the upper bushing to wear also, and so the whole shaft was basically moving all over the place via gyroscopic force at speed...

Anyway-- With the carb fixed and tuned for our altitude, and a distributor that always fired, and at the right time too, we never had another running problem. And for what it's worth, I changed out the Holley for an Edlebrock, and guess what? After numerous experiments with jetting, I ended up with "perfect" being exactly how it came out of the box. And guess what part II? The Edlebrock didn't change a thing. Nothing. Holeshot, cruise, WOT, top speed, cold start, warm start, and fuel mileage-- Absolutely unchanged. Still, I like Edlebrock's better than Holley's

Assuming all else is in order (cam timing etc) if you have the proper amount of fuel, and a good spark at the right time, an engine is going to run decent. Tracking down the culprit(s) can be frustrating, but it's great when you get it running great!

 

[JaseBosto]

Re: Boat will not run right...

Thanks for all the replies. It is a 1990 501A, volvo penta GM 305 v8. I went to napa and got a fuel pump for a 1986 chevy pickup with a 305. That should bolt to the side of the motor no problem. The engine itself wants to run fine it appears. When I powerload(on a ramp that allows it!), I can give it short bursts of throttle no problem. In addition, when not under load the engine will stay at high rpm all day if I let it. IF I have to pull the distributor I feel like I may have to pull the engine for that because there is little clearance above the engine.

 

[frantically relaxing]

Re: Boat will not run right...

Sounds like your starving for fuel, and the new pump may help with that diagnosis-- However, you DO NOT want that truck fuel pump on that boat for any length of time, you need a marine pump- the difference is the marine pump has a nipple to connect a yellow overflow tube to, which runs to the carb. Your truck pump does not. If the pump diaphragm should leak for any reason past the fuel side into the dry side of the pump, it has to escape somewhere-- in a marine pump it escapes up the tube and into the carb. In a truck pump, there's simply a vent hole, and the fuel drips on the ground. In your boat, the "ground" is your bilge, and any fuel in the bilge is an explosion waiting to happen!

 

[JaseBosto]

Re: Boat will not run right...

Sounds like your starving for fuel, and the new pump may help with that diagnosis-- However, you DO NOT want that truck fuel pump on that boat for any length of time, you need a marine pump- the difference is the marine pump has a nipple to connect a yellow overflow tube to, which runs to the carb. Your truck pump does not. If the pump diaphragm should leak for any reason past the fuel side into the dry side of the pump, it has to escape somewhere-- in a marine pump it escapes up the tube and into the carb. In a truck pump, there's simply a vent hole, and the fuel drips on the ground. In your boat, the "ground" is your bilge, and any fuel in the bilge is an explosion waiting to happen!

Ok. I will heed that warning well. It appears that there are just as many hookups on the truck fuel pump, as the one thats on the boat. There is a line hookup that looks just like the one on the marine pump. I will take pictures of both pumps, and you can tell me what you think.

 

[JaseBosto]

Re: Boat will not run right...

I have elected to just put in a marine pump. This one is not the same.

 

[500dollar744ti]

Re: Boat will not run right...

You need a marine fuel pump, it's a safety item on a boat.

 

[JaseBosto]

Re: Boat will not run right...

Update. The fuel pump has been replaced , and the boat runs great. In hind sight, the boat would die out when the secondaries opened up. Now it appears to run good. There is a brief pause when the secondaries open but this appears to be normal.