keeps running out of gas

[h2ocwilly]

I have a 82 23' Formula Thunderbird with a 260 mercrusier that will run great for about 10 to 12 min then it just runs out of fuel. I can't figure out if its the carb or something downstream towards the tank. It has two fuel pumps, mechanical and electric. The mechanical is brand new and the electric seems to run fine. The fuel filter/water seperator is brand new and shows no signs of water in the tank. The vent seems to be clear as I can blow air thru with the filler cap off. I have even opened up the carb and cleaned out the bowl. I put it all back together and it runs great till 10 to 12mins. I've pulled the linkage off the carb and manually tried pumping the fuel but the carb seems to be dry. Is there some kind of valve between the tank and the fuel pump that could be giving me my headache? Help, please.

 

[Don S]

Re: keeps running out of gas

The link below will help you find exactly where the problem is.

http://forums.iboats.com/showthread.php?t=167561

 

[Haut Medoc]

Re: keeps running out of gas

I have a 82 23' Formula Thunderbird with a 260 mercrusier that will run great for about 10 to 12 min then it just runs out of fuel. I can't figure out if its the carb or something downstream towards the tank. It has two fuel pumps, mechanical and electric. The mechanical is brand new and the electric seems to run fine. The fuel filter/water seperator is brand new and shows no signs of water in the tank. The vent seems to be clear as I can blow air thru with the filler cap off. I have even opened up the carb and cleaned out the bowl. I put it all back together and it runs great till 10 to 12mins. I've pulled the linkage off the carb and manually tried pumping the fuel but the carb seems to be dry. Is there some kind of valve between the tank and the fuel pump that could be giving me my headache? Help, please.

The anti siphon vave comes to mind as well as the fuel tank pick up....
Try rigging a separate six gallon tank for testing & see if you can recreate the symptom, if you can't, you will know where to focus your attention.....

 

[erikgreen]

Re: keeps running out of gas

This motor sounds like someone band-aided it... it's supposed to have either a mechanical or an electric pump, not both....

 

[Bondo]

Re: keeps running out of gas

it's supposed to have either a mechanical or an electric pump, not both....

Ayuh,.... Get Rid of the electric Pump,..... It doesn't belong on that motor....

Being a 1982,... It could be a collasped fuel line....

 

[h2ocwilly]

Re: keeps running out of gas

Thanks guys, you've been a real help. I will put all of your advice to work and hopefully all my headaches will go away.

 

[backwater dawg]

Re: keeps running out of gas

Don's prob correct---that same thing happened on my 1988 260--I have Twin motors and only one would die---my prob happened to be collapsed fuel lines---my boat is 20 yrs old and your's is 26ish---the lines look good from the outside but the inner walls get soft and under suction they collapse---cheap mantainence to replace the lines----or there's a little screen in the front of the carb---right where the line screws in---when my boat was new---2400 hrs ago--- both sreens plugged a couple of times as all the filings came through---I've learned to clean those every couple of yrs---both cheap tries---good luck Steve

 

[h2ocwilly]

Re: keeps running out of gas

OK I found the problem. I narrowed it down to the line that enters the tank. Now I tried to remove the tube that goes down into the tank but it stops at the very end when I pull it up out of the tank. How do I get this thing out?

 

[Don S]

Re: keeps running out of gas

Pull harder. Sometimes the metal screen on the end of the tube gets pushed out of shape and makes it hard to pull out.

 

[sarantis]

Re: keeps running out of gas

i had similar problem .Replacing the fuel hose with a flexible tranparent one i found out that after 2-3 minutes runing at wot (depending on how much fuel there was at the tank) it started geting filled with vacuum bubbles up to the point that the fuel stopped runing at all.I untightened the fuel filling cap and i replaced the anti siphon valve and the problem remained.So i took out the metal hose that goes into the tank.The screen pick up was clear.So what is left is much dirt to the fuel that clogs the pickup when runing at WOT because then it sucks much more fuel,the dirt clogs the pickup and ater the engine's stop the dirt falls again to the tank.Hence after a while the engine starts again normally.