Fuel problem causing stalling after 30 min

[jerryb1]

I have a 1980 sea ray I/O with a GM V8 model 260 I believe. The boat runs fine for about a half hour, then it dies. It restarts and acts like it's starving for fuel. If i can get it to idle, it dies as soon as I try to put it in gear. I had a similar problem once before and it was a clogged filter/water seperator. I replaced that and I thought I fixed it, but it was only because it was cooled off. I don't think it's electrical, but maybe it could be the coil acting up when hot.
My question is - What else would exhibit not working after about 30 minutes of running fine. From other posts I see it could possibly be the fuel pump, carb(Rochester 4bl) or the anti syphon valve. Would these exhibit a failure after 30 minutes?
I've been keeping Sea Tow busy!
Thanks

 

[Uraijit]

Re: Fuel problem causing stalling after 30 min

Have you checked to see whether you're getting spark when the problem happens?

You need to isolate whether it's a fuel, or a fire problem, before continuing on.

If you're gettin spark, move onward to fuel...

I'm fighting some fuel issues right now, myself, as a matter of fact...

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

Thanks- Since it runs at high rev's, I didn't think it was spark related, but I probably should change the points and condensor at least. I was trying to avoid checking/changing a lot of things, that is why I was hoping someone on this site would recognize the problem. I don't want to replace ten things as a Marina might do and most likely one of them would solve the problem.

 

[Uraijit]

Re: Fuel problem causing stalling after 30 min

It could be one of several things, but if you can verify whether or not you're getting spark, you cut your search area in half, because you know whether you're looking for electrical problems, or fuel problems. You said you thought it might be a coil. Doing a quick spark test is the easiest way to eliminate that possibility.

Don't just go buying a coil/fuel pump/whatever else, and slapping it on there.

Go through it, and figure out what the problem is, before throwing parts at it.

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

I agree 100% regarding just changing parts. I have had the boat for 6 years and never changed the fuel pump. I don't know if it's original. it may be. The boat/engine has about 500 hrs total.
The problem is getting it warmed up without getting stuck. I guess I can just run it at the dock for 30 minutes.

 

[Fishermark]

Re: Fuel problem causing stalling after 30 min

Among the simple things you can do is to check to make sure the choke is opening fully after it is warmed up. Once it does its "dying/hard to start routine" pull off the flame arrestor and make sure the choke is fully open.

Also pull a plug wire and check for a good hot spark. I would do that check before running it and after it warms up and dies. That will give you a point of reference to see if there is a difference in the spark you see.

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

Thanks- Great suggestions! i never thought about the choke!! I'll check both this weekend.

 

[chiefalen]

Re: Fuel problem causing stalling after 30 min

Where in jersey are you? Did you check the the filter in the fitting bye the carb?

The filter in the fuel pickup. The anti-siphon valve.

You could try to pump the water and gunk out of the tank.

Boat on trailer jacked all the way up, Pull the fuel pickup stick a hose in tank all the way in the back corner and using a cheap auto electric fuel pump, pump the water out into a clear container till you see fuel . Then stop.

Water is heavier than fuel.

Also you could try running it on a external tank of fuel to see if it is truly a fuel problem.

Anything unusual like over heating when you run into the problem?

One other thing check your vent to the tank. Could be causing a vacuum condition. When the problem happens open the gas cap do you hear a rushing in of air?

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

Thanks for your suggestions. Since it runs fine at first I don't see how the filter by the carb or other non moving parts can only clog when warm? Is that logic correct?
I took off the water seprerator filter and dumped the gas inside it into a clear glass,. I didn't see any water on the bottom. How do I check/clean the anti syphon valve?
The boat is in Bricktown near Kettle Creek.

 

[chiefalen]

Re: Fuel problem causing stalling after 30 min

Follow the fuel hose back from the fuel pump, where it enters the fuel tank is a fitting that is the anti-siphon valve-one way valve. Take it off blow thru it, sticking full of stuff?

Under the fuel anti-siphon valve is the fuel pickup tube, pull that there is a screen on it, dirty?

Fuel pump giving you enough pressure, check that with a gauge. How mush pressure it giving you?

Oh yea screen gets clogged shuts down the engine, no pressure gunk falls off the screen. 30 minutes latter screen gets clogged again. Over and over. Clean the screens run the motor clean the screens again. 3-4 times till it's clean.

When i first got my boat i cleaned the screens alot.

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

I fixed the problem!! Thanks to everyone's suggestions. Especially Chiefalan who asked if there was any overheating problem. I didn't exactly have overheating but the temp gauge was running hotter then it usually did. It made me suspicious.
I checked the filters, gas for water, anti syphon valve pick up screen and they were all clean.
I changed the ignition coil and took out the thermostat. It ran great yesterday all day wih no problems.
The problem was one of the two(either the coil or engine runnig too hot(vapor lock maybe?).

 

[EarlyWood]

Re: Fuel problem causing stalling after 30 min

just curious, are you stlll running it without the thermostat?
I can run my engine without thermostat and think it's ok, but when I pull the plugs, water comes shooting out the plug holes... i think that's not good ))
....but she runs fine for awhile

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

For my situation , running without the thermostat is okay, because my engine heats up to normal operating temperature. Engines are designed to operate at a certain temp, not too hot nor not always cold. That is why they use thermostats to control the water flow.
The thermostat has nothing to do with water in the cylinders. That is a serious problem, requiring an engine overhaul. Are you sure it's water? I can't beleive the engine runs okay!

 

[EarlyWood]

Re: Fuel problem causing stalling after 30 min

We probably have unrelated issues, other than I can have my temp gauge tell me things are good even when they're not. My engine would eventually stall due to an overheat plus water in the exhaust manifold/leaking or getting sucked into cylinders. She does run fine though since the issue hasn't gone to full blown hydro lock...it's my intention not to let that happen.
Check this out
http://forums.iboats.com/showthread.php?t=275203

 

[Maclin]

Re: Fuel problem causing stalling after 30 min

jerryb1,

Running without a thermostat can actually let the engine get hotter. The water needs time to absorb the heat. The temp gauge will show cooler temps but the engine will not be cooling evenly and efficiently in most cases.

I am not sure why your problem went away but running without a thermostat is not a solution to very many problems, I'm just sayin'.....

 

[jerryb1]

Re: Fuel problem causing stalling after 30 min

I plan to put a new thermostat in in a few weeks when i pull the boat for the season. Your logic makes sense regarding the fromt cylinders, but with the thermostat in the rear end of the manifold where the sensor is, it was too hot. I probably have partially clogged risers or something as it should be running colder with no thermostat.