mrshocky

Got a 1984 Chevy c-30 motorhome and got stuck in Mojave, new pump didnt work so we put a Faucet electrical fuel pump on it totally bypassing the mechanical one. Ran great for about 80 mile and started surging like it wasn't getting enough fuel, got really bad when the tank was just under a quarter tank. Any Ideas what could be causing this? Thank You. Bob

SWHouston

Welcome to the Forum Bob.
Probably a stopped up filter. I always remove any obstruction like that and put one I can access in-line where you can replace it easily.
You might be able to just blow it off the end of the Tank like with Air Pressure. If not, you got to remove the Tank and get a straight open line out.
Hope you installed the Pump at/back toward the Tank, they push better than they pull.
What pressure pump did you get ?
You might think about pulling the Tank anyway, sounds like you bought a load of trash along with your Fuel.
Also, they make little Caps you can bolt on to the Engine where the Mechanical Pump goes. Totally remove the M-Pump.

mrshocky

Thanks this a cool site. Tank was dropped and was really clean, all rubber lines have been replaced. The small ice cube Faucet electric pump that put out 4-7 pounds and is a 32 gph is the pump that got put in. I reinstalled the pump back by the tank but its 12 to 15 feet from the motor and 2 feet lower than the carb. Starting to think I need something bigger with higher pressure because of how far it is from the tank.

SWHouston

Possibly, they make one that goes up to 9psi and has a higher lift than the one you're using, and more, like 11psi with 36" lift. If you're wrong, at least you'll have a spare pump to stash in case. I'd definitely try it.

This is not related, but do you have/use House Batteries or a Generator ?

mrshocky

Got a fuel pressure gauge today and I'll check the pressure at the end of the hose at the carb and see what I got. Probably going to get a bigger pump and regulate it down if needed. Its a Lazy Daze motorhome with no generator, but I use a portable generator when needed. It does have a house battery that is new.

SWHouston

Good choice. Best check what psi your engine/carburation require, and go from there. I still think you're going to wind up getting a bigger Fuel Pump.
Be sure that you maintain greater than 12.4 VDC on that House Battery when it's not being used. A situation called "Sulfaction" is created when you store/don't use a battery for a while and you let it drop below the required storage voltage. So make sure your Battery Maintainer is doing it's job.

mrshocky

Thanks for the info, I'll let you know what I find.

mrshocky

Tore apart the fuel inlet into the card today and found the problem. Caught in the opening of the carb fuel filter was a piece of hose lining. Removed the filter and replaced it with an inline fuel filter, runs like a champ. Thanks for your help.

mrshocky

Took the motorhome for a highway run today, ran great for awhile then noticed the problem again only in a hesitation. took it home and shut it off opened the hood and no fuel in the filter. turned the key on and the pump came on but still no fuel in the filter. Started the motorhome went out looked at the fuel filter and it was bubbling. Felt the fuel line and it was warm. I'm sure its vapor locking. Still think the pump isn't big enough. Any ideas? One thing I did notice is that the fuel filter never gets full even when the motor is cool.

SWHouston

You said you found a piece of hose blocking the flow...
Do you have a Flex Line running to the Tank, or did it come from some Flex connector inline ?

Either would suggest that it's old and needs replacing.

If you have a Flex Line all the way back to the Tank, then it will be very easy to re-route it away from any serious heat source should you replace the whole thing. If it steel now, you might think about going to Flex, and correct the route as necessary, but...

Bubbling !, you might have an Air Leak between the Pump and the Tank. That's the only place it could draw air into the line. That includes any crack of the Pickup Tube inside the Tank.
Have you been inside the Tank, checked that, removed any filter on the end of the Tube ?

Sometimes, if you don't have your (exposed) Inline Filter orientated sufficiently, it could hold a little air where you could see it. But, I wouldn't worry about that, until you got the bubbles issue settled.

If it worked (drove out) satisfactorily for a while, the Pump is probably sized well enough for now.

So...
Get the "trash" issue settled first.
Pull the tank, check and clean,
Replace any/all Flex, reroute if necessary,