Fuel pump stops after 10-15 minutes

[stealthdrummer]

I have a BBC with no provisions for a mechanical pump so I have to run an electric. When I bought the boat it had a small Mr. Gasket micro pump (automotive) and rubber fuel lines. I replaced that with a Holley Red marine unit, braided SS lines and all of the safety switches needed. The boat ran fine with the other pump it just wasn't safe. The new Holley pump will run for 10-15 minutes get hot and just shut off. The carb has enough fuel in it to let the motor run long enough to verify that the oil pressure switch is delivering power to the pump. The SS lines are -6AN from the tanks (one on each side of the boat) to a tee, coarse pre-filter, PUMP, water seperator/filter, carb. The line length is about 2 feet from one tank and 6 feet from the other tank to the tee. These lines run horizontal from the top of the tanks. From the tee there is 18 inches straight down to the pre filter and then straight into the pump. I know that electrics push fuel better than pull it but I find it hard to believe that a cheap pump using the same size lines would out perform a dedicated marine style pump. What am I missing. This is the third weekend in a row of fuel pump issues.

 

[Dothedew]

Re: Fuel pump stops after 10-15 minutes

Thats a weird one. I'm assuming first off that its a low pressure pump, as in 6 psi or less? Can't remember if the blue or red was low pressure. If its a higher pressure, it'd flood the carb, but that doesn't sound like you're issue. I'd try perhaps a different power source, just for the hell of it. Run a long fused wire right from the battery to the pump and go for a stroll, just to be sure. If it cuts out after that, I'd suspect its a pump issue. They do get warm, but fuel running through them should keep things somewhat cool, but not hot.

 

[stealthdrummer]

Re: Fuel pump stops after 10-15 minutes

The red pump is low pressure.
I hot wired the pump with fused 10 gauge wire straight from the battery in the driveway and started the motor and watched the fule press gauge. After 10-15 minutes the gauge drops to zero and the carb runs out of fuel. I am wondering if the lines coming from the tank are too long for the pump to suck enough fuel to keep itself cool. The down side to that is there really is no other way to get the fuel to the pump short of having some outlets tapped into the lower part of the tanks so the weight of the fuel is "pushing" to the pump.

 

[Eric 3.7LX Alpha 1]

Re: Fuel pump stops after 10-15 minutes

Hi,

The water separator/filter should be on the suction side of the pump not pressure side, there was a heated thread on that very subject couple weeks back.

I have my dual tanks both entering the separator independantly, and have one outlet going to my mechanical pump then engine.

I don't think that is causing your problem but wanted to bring it up.

Do you close off one tank at a time or run both together? The Fuel tank vent which is on the side of the hull might be blocked causing the tank to be under a vacuum after 5-10 min. of use making it difficult to suck from.

You could try running the engine with the fill cap off (while on muffs), or run the fuel pump from a portable container while on muffs and see if it cuts out the same.

Just a thought.
Eric

 

[stealthdrummer]

Re: Fuel pump stops after 10-15 minutes

I tried running it with the caps off the tanks and had the same results of the pump quitting. The pump pulls from both tanks at the same time. I bought a cheap Mr. Gasket Micro pump that I am going to try in the driveway this afternoon using all of the same lines to see if the Holley pump is bad or if there is another problem.

 

[Don S]

Re: Fuel pump stops after 10-15 minutes

It's very possible that your Brand NEW electric fuel pump is defective right out of the box. Wouldn't be the first new item that didn't work right.

 

[jtmarten]

Re: Fuel pump stops after 10-15 minutes

Doesn't matter what type of automotive pump you try, you'll burn 'em up quick. They key here is "the pump pulls ....". Thats your problem. Auto electric pumps are designed to push the fuel from a gravity fed tank, not pull it from the tank. Pulling it from the tank puts too much load on it, and the pump overheats and dies.

I doubt the Holley red marine pump is designed to pull the fuel, just electrically safe. I'd contact them and see what it is rated for.

I had a Carter electric marine pump on my jetboat when I bought it; it worked fine for a few trips then died. Tried several Holley reds that burned up quickly, decided then to switch to a mechanical pump.

 

[stealthdrummer]

Re: Fuel pump stops after 10-15 minutes

Turns out the pump was bad. I replaced it with a test pump and the boat ran with no problems for about 20 minutes. I contacted Teague marine tech support and they said that they quit selling the Holley Marine Reds due to problems. They recommended an Aeromotive marine pump that will pull the fuel from the tanks as well as push it to the carb. It is double the money of the Holley but to not have anymore headaches, wait....did I just say that?, would be great. Off to the lake to test it out.