Engine Dies...

[Lone Star 30]

I HAVE A HUNTER 30 WITH A YANMAR 2GM20 16 HP. I DECIDED TO CHANGE BOTH FUEL FILTERS SINCE IT WAS SOMETIMES HARD TO START AND OTHERS IT WOULD FIRE RIGHT UP, BUT ALWAYS STARTED.SINCE I CHANGED FILTERS IT WILL ONLY START IF I PRIME THE FILTER ON THE FRONT OF THE ENGINE AND BLEED OFF ALL THE AIR FROM THE FUEL PUMP TO THE FRONT FILTER OUTLET, AND THEN IT WILL ONLY RUN FOR ABOUT 5 MINUTES OR UNTIL IT USES UP ENOUGH OF THE FUEL FROM THE SMALL FILTER TO TAKE THE FILL LINE BELOW THE OUTLET PORT OF THE FILTER.
THE ENGINE ONLY HAS 497 HRS BUT IT IS A 1989. THE LARGER FILTER WAS UNBELIEVABLY DIRTY. BLACK GOO AND CRYSTALIZED PARTICLES GALORE ON THE RACOR FILTER AND IN THE BOWL. I DON'T KNOW HOW IT WAS RUNNING.
I THINK I NEED TO CHECK THE PUMP ITSELF.
DOES ANYONE HAVE ANY IDEAS OR KNOW WHERE TO GET A REPLACEMENT KIT OR DIAPHRAM?

[Alan Wheeler]

Can I suggest you don't sit so close to the engine when it is reving. It's damaging your hearing, because writing words using all captial letters is considered yelling;-) :-)

[scotte]

You have an air leak somewhere. I would suspect anything you touched or changed. Did you get all the gaskets and O-rings replaced and seated? All the fittings tight (but not TOO tight)? Look for any wetness around fittings and joints, the filter bowl, etc as a hint. Just remember that air getting in doesn't mean fuel is getting out, but it's an easy thing to check for any obvious leak.

[hellosailor]

I'd second the tought of an air leak. if there are crush washers (thin copper foil washers) on any of the joints you touched, those MUST be replaced every time to touch the joints, or they will allow air leaks to occur.

Like White Castle hamburgers: Buy the big sack, you'll go through them.<G>

[Kanani]

Originally Posted by drh1965

Ah... I'm starting to understand how you feel. Seems that's a virtue of buying an older boat

I think I've got the problem licked now... I cleaned the pickup with a wire and bled the system again. The engine ran for an hour after that. Hopefully, it was something stuck in the pickup.

I would bet that the problem will return and it may well happen when you need your engine most (that's usually the case).

I would recommend having your tank power flushed. It could just be that you have a lot of sediment or algae in the tank.

I would also recommend getting yourself a small hand vacuum pump. Put vacuum on the line that attaches to the tank. It should hold vacuum. If it doesn't, you have an air leak in the lines somewhere. If it does, you don't have an air leak in the lines. It's as simple as that.

The next thing is to check for an air leak in the pick-up tube (inside the tank). Get a 20" long piece of clear plastic hose and attach it to the tank (where the fuel hose attaches). Draw the hose full of fuel (holding the hose straight up. Plug the hose securely and the fuel should stay in the hose. If the fuel level lowers, you have a leak in the pick-up tube.

From what you've said, my money is on sludge in the tank.