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A few months ago I installed a Walbro 24 volt electric fuel pump, part # MS-51321-1.
It worked great until this week. Now it just "clicks" once, shoots out a spurt of fuel
and does not continue to run. I removed the pump and hot wired it directly to
the 24V. batteries. No change.
This pump is NOS and never used before.
Took the bottom cap off the pump. Nothing to see here. Screen/filter is clean.
All fuel is pre-filtered before the pump.
There does not seem to be any way to disassemble the pump further.
Could the ethynol blended fuel have destroyed this NOS pump in such a short time?
I've got pic's on my gallery of the setup.
Any thoughts or comments appreciated.
Jerry

I put a Walbro electric fuel pump in also. It lasted about three years ( about 5000 miles) of fairly steady use. I replaced it with another Walbro same model. I think these fuel pumps by design, lead a rough life. I chose Walbro because I had heard good things and they were about the most expensive. I was going on the hope that you get what you pay for.

If it's a sealed contact unit you can sometimes open them up with a 1/4 turn anticlockwise at the head and clean the contacts, also, they can jam on the bore not quite at the top of the stroke and as a result not actute the contact set or magnetic sesnor (types vary) so drying, flushing, cleaning and reassembly can sort them out, in a pinch I have even tapped them with a rubber hammer to get them ticking away again...

HOWEVER!!!!! - DO NOT operate the things on the bench without fuel flowing through them in a closed loop or completey flushed with methylated spirit and dried as some have a wet contact system (stupid huh??), most pumps won't fire if there is insufficient fuel or the internal filter is blocked as a safety measure but if you manage to cause a spark off the contact set in fuel vapour you will be holding on to a potential grenade

MM

Monkey Man wrote:If it's a sealed contact unit you can sometimes open them up with a 1/4 turn anticlockwise at the head and clean the contacts, also, they can jam on the bore not quite at the top of the stroke and as a result not actute the contact set or magnetic sesnor (types vary) so drying, flushing, cleaning and reassembly can sort them out, in a pinch I have even tapped them with a rubber hammer to get them ticking away again...

HOWEVER!!!!! - DO NOT operate the things on the bench without fuel flowing through them in a closed loop or completey flushed with methylated spirit and dried as some have a wet contact system (stupid huh??), most pumps won't fire if there is insufficient fuel or the internal filter is blocked as a safety measure but if you manage to cause a spark off the contact set in fuel vapour you will be holding on to a potential grenade

MM

Since the pump is relatively new, I've been reluctant to tear into it. I'll try flushing. Would you suggest carb cleaner?
The unit is a casting with only access through the bottom cap... held on by three machine screws.
Don't like the sound of that word "grenade." Sounds like thoroughly drying before testing is the way to go.
JB

Carburettor cleaner should be fine, do the work in a very well ventilated area though, that stuff can be a bit unfriendly if you breathe too much and make sure you wear suitable rubber gloves. Most piston type fuel pumps, if not used regularly can stick in the bore with varnish, grotty bits in the fuel or just develop plain old electrical faults.
Mazda use to or still makes a fuel pump that is like a small mains transformer to look at, very quiet, power efficient and reliable (so long as there is a fuel filter to catch the rubbish before it hits the pump) plus it can bolt to the frame and simply replace the joiner on the rear drivers side just forward of the tank (does need line fitting adapters but these are easy to get).
I like to run a mechanical pump with an electric pusher pump as well so you can simply bypass the mechanical pump and switch to electric as a repair or if the pumps valves start to break down while on the road you can switch the electric pump on to get off the highway and get it fixed. One problem with that setup is if you drive on without checking the problem and the the diaphragm is dead in your mechanical pump you can quickly flood your sump and oil with fuel and cause more problems.
The single smartest thing to do with any type of fuel pump to alleviate any type of fault is..........Carry a spare

MM

Thanks MM,
You may be on to something. I only used the elec. pump to prime the system after the truck had sat idle for
weeks. Then always turned the elec. pump off after engine started. The mechanical pump took over.

Because I tried to regularly start it, there was no need for elec. pump priming. That being said, there is still
some times the M sits idle while (whilst, for MM) busy on other projects.

You can see the mondo fuel filter on my setup, so crud from the fuel tank is not the problem.
I'll try carb. cleaner today and see if that helps.

Jerry

Years ago I bought a crapload of M113 APC pre-heater kits because they had a 24V Walbro pump in them (they were cheap then).

The pump in that service was built for Diesel fuel. I tried one on a gas truck and it pooped out fast. On Diesels, they ran a long time.

Might be the answer.

PoW

PoW wrote:Years ago I bought a crapload of M113 APC pre-heater kits because they had a 24V Walbro pump in them (they were cheap then).

The pump in that service was built for Diesel fuel. I tried one on a gas truck and it pooped out fast. On Diesels, they ran a long time.

Might be the answer.

PoW

Dennis,
You may be on the right track. Got my NOS Walbro pump at the PHX show and swap meet. Very possible it was spec.'d
for diesel. MM suggested carb. cleaner. Did that.... no change. Also checked the voltage going TO the pump. It's well
over 24V. The pump, in it's current condition, is a small boat anchor.
Guess I'll try to pull it apart. After all.... some human being put it together. My wife says I'm ALMOST human.
Jerry