Can't hold an idle and out of ideas

[Efini Motorsport]

I've been trying to help my dad work on his 88 Bayliner Cierra. It has an OMC cobra with a Chevy 350 and at this point I'm out of ideas as to what could be his issue. We pulled the engine last winter because of a bad oil leak and a leak in the gas tank. The engine got a new oil pan, valve cover gaskets, water pump gaskets and a few other minor things. The gas tank was cleaned and glassed on the outside and coated with red coat (a tank sealer) inside. Everything went back in this spring and it's been a headache ever since. So far we've replaced the carb, fuel filter and fuel pump and checked all the hoses, The pump is pumping as it should be. The red coat did clog up the fuel pick up tube so that was cleaned out. The engine starts fine and idles fine until it gets up to temp It will run up to about 1.5-2k rpm for a while then slowly lose power and die. we idled around for probably close to an hour before it really started acting up and then we couldn't keep it running at all. It would start right up but then quickly die out. That was with the original carb and fuel pump. Both were swapped (went from a rochester 4 bbl to an edelbrock 4 bbl). The problems actually got worse at first which is how we found the clogged fuel tank pick up. Cleaning it didn't help any. I'm in CT and he's in ME so I can't see things for myself so I'm trying to pass along any ideas I can think of for him to try and right now I'm out of them. Anyone got any they can spare?

 

[Tnstratofam]

Could be a bad anti siphon valve. Did you replace it when you redid the tank? Also what about the tank vent. Is it clear?

 

[Efini Motorsport]

Not sure on the anti siphon valve but pretty sure he didn't. I'll have him check the vent too.

 

[Lou C]

If its original it could be really corroded. That was a problem on my boat when I got it back in 2003, the shop put on a better quality Evinrude/Johnson one and its been fine ever since. Mine would rev fine in neutral but would not plane out the boat.

 

[Efini Motorsport]

He said he checked the valve and it blows one way but not the other. He didn't check the vent yet. I'm relaying ideas to them as people offer them.

 

[Bondo]

Ayuh,..... Pull the fuel filter, 'n examine it's Contents for anything but clean fresh gasoline,......

I'm guessin' Dad will find more crap, or more tank sealer,....

Run the boat with a remote tank of fresh clean gasoline, hooked directly to the new fuel filter,.....

If it runs Great, ya got a tank issue,.....

If it still pukes, it's the fuel pump or carb,.... or points in between,....

 

[Efini Motorsport]

OK. I'll let him know and report back. It may be a day or two before he can try it out.

 

[Efini Motorsport]

Talked to him this morning and he got it running. Turns out he has the vacuum line that runs from the fuel pump hooked up to the carb which caused the fuel pump to not be able to pump properly. Thanks for all the help.

 

[Lou C]

Do you mean the yellow tygon overflow hose that goes from the pump to the carb? This is to safely route gas from the pump to the carb if the pump diaphragm leaks, its is not a vacuum hose. I think you are going to wind up replacing that gas tank personally. Is it an aluminum tank that was repaired by ‘glassing on the outside and putting sealer on the inside? That does not sound like a safe and proper repair.

 

[Efini Motorsport]

Yes that hose. Where on the carb is it supposed to route to? The sealer he used is called red coat and it is made to seal gas tanks. He is planning on selling or trading the boat to get something smaller

 

[Lou C]

There will be a fitting on the carb, that usually is on the air horn (upper body of the carb)….on a Rochester Q-Jet its in the front, on a Holley, it is off to the side. It has nothing to do with vacuum, it is just a safety feature if your fuel pump leaks. So if there is ever gas in that hose, the pump is bad. This is why you should never use an automotive mechanical pump on a boat, it will leak gas right in the bilge causing an explosion risk. Gas tank sealers make me nervous, does he have to use E-10 gas? Is that sealer rated to be safe with E-10? If not then I would not even sell that boat with the tank "Fixed" that way, too much liability. I'd sooner lose money on a sale than have that to worry about....

 

[Efini Motorsport]

I just called the company because I wasn't sure if ethanol had any effect on it. They said they've test is on everything up to e100 with no issues of break down so e10 shouldn't be an issue. Glad you brought it up though as I didn't know. I know he did use a marine fuel pump.

 

[kpg7121]

I just called the company because I wasn't sure if ethanol had any effect on it. They said they've test is on everything up to e100 with no issues of break down so e10 shouldn't be an issue. Glad you brought it up though as I didn't know. I know he did use a marine fuel pump.

Why'd you seal the inside of the tank? I'd do as Bondo suggested & go from there. Sounds like a tank issue to me.