Electric fuel pump for Weber carb?

Hi Chaps.

To cut a very long story short…. I’m currently on my 3rd mechanical fuel pump in a year, approx 500 miles. They all came from Heritage and all of them seem to work fine for a little while then start playing up.

So to get rid of this annoying issue I’m thinking of fitting a low pressure electric fuel pump and doing away with the mechanical pump, swirl pot and return line, I’ll connect direct from the pump to the carb. (Weber 32/34 dmtl fitted)

The pump I’m thinking of fitting is from Heritage as well, it’s branded USA, and described as a rotary electric fuel pump, comes with an in line filter and is self regulating from 2 to 4psi.

has anyone done this already, it seems pretty straight forward and gets used a lot in the air cooled world.

ive had the all to common fuel starvation issues in the past and got around this by fitting a welding tip in the fuel return line, the only running issue I ever have is pump failure.

Any comments much appreciated

cheers.

 

Not had any problems with my mechanical fuel pump so can't help with new electric one but it's not a good idea to get rid of the return fuel line in case to much fuel goes to the carb and it's got no where to go other than out of the carb on to the hot exhaust manifold underneath the carb as an engine fire my be your next problem…  

Hi Mark and thanks for the response, when I first got the car it had the original vw fuel pump fitted, it worked fine but leaked oil from the flange as it became warped over the years. I replaced this with a pump from heritage to cure the oil leak, job done I thought.

After only a couple of hundred miles I then experienced really poor starting issues, one day when it refused to start so I pulled the pump and noticed the lever has jammed, freed it up but it jammed again a little while later.

Replaced that pump with a new one and immediately noticed an improvement in pump pressure, all was well for quite a while but… took it out last weekend, stopped for a coffee after approx 30mins, started up ok but spluttered a few mins later, pulled over, revved it a little then all was well again, drove home, another 30mins, pulled on the driveway then it cut out and refused to start.

I noticed the fuel filter was empty and on cranking the accelerator pump on the carb there wasn’t any fuel squeezing in.

So again I removed the pump and cracked the lever a couple of times until I heard fuel in the carb, now back to normal running but don’t trust it again.

Regarding the electric pump, it has a built in regulator so shouldn’t over fuel but an additional regulator could be fitted I guess as belt and braces.

 

I've not looked into electric fuel pumps so Im probably wrong about a fuel return line if the fuel pump will supply the right amount of fuel.  


 With my Mk1 Scirocco the fuel return line is straight out of the carb via a rubber hose then straight onto the solid fuel line back to the tank, not sure if yours is the same?

I run a Huco 133010 electric pump on my dual 45s. It's self regulating at 2.1psi. Not to expensive either.

Hi Mark1gls. Yeah I think a low pressure pump specifically for carb use will be fine as they are only a couple of psi, as far as I can see a return isn’t necessary due to been regulated, but more investigation required though.

On the golf the pump feed goes to a swirl pot first, this has an outlet to the carb and also has an outlet for a return line back to the tank, currently my return has a welding tip in it to reduce the flow back to the tank (common fix) without this it cuts out every hundred yards, I’m sure the weak pattern mechanical fuel pumps have a lot to do with this problem.

Hi nedrager. I’ve had a look at that pump and it looks very interesting,  as it’s a suction type it can be mounted in the engine bay instead of next to the fuel tank, much easier.

What filter are you running and did you fit the safety cut off relay too? Cheers

My first experience with a electric fuel pump on Carbed cars was my 67 MG Midget.  Worked like a champ, until on a "First Date"I was stranded in the middle of no where as the wire to the pump decided to break.

After an hour or so of necking, I jacked the car up, found the wire, and using the strip and twist the wires together with black tape to secure got my date and myself home.  

The next day I was soldering in a proper splice.

If you still have your original pump you could refit it with 2 gaskets which may be enough to take out the distortion on the flange and stop your leak? 

Sorry for the radio silence guys, I’ve been doing a bit more research and also had an interesting chat with an old school mechanic I know.

Im now thinking the underlying problem I have is maybe vapour lock, given the last time i had a problem was on a very hot day, after a half hour drive or so I pulled on to the drive, open the gates and drove up to the garage, that’s when it just died, no fuel in the filter or carb when I checked shortly afterwards. After pulling the pump and cranking by hand I got fuel again and all was well.

I’ve been out a couple of times since in not so hot weather with no issues at all.

Given a vapour separator / swirl pot is fitted to the golf to stop this issue I’m a little confused, the one fitted is nice and shiny so not that old, the mechanic I spoke to told me it used to be quite a problem in the past with all the carb’ed cars with mech pumps about. In slow moving traffic or at a stand still the mech pump temperature can get high enough to start boiling the fuel, creating vapour and eventually creating vapour lock.

Any of this rings true with you guys

 

Yes, my father had a Dodge that would do that, one Mechanic he took it to wrapped all the fuel lines Coming in to the engine bay with insutation and foil tape in the engine bay and that stopped it.

Do not confuse vapor lock with the swirl pot.  That is designed for fuel starvation in turns.

Do you have a upper radiator card installed on your Radiator if yes good, if no then do it.
IT prevents recycling of the engine compartment air from going back over the radiator at a stop. and allowing the engine compartment air to get even hotter.

I never had that type of issue on my MG's, Rovers, or Bug-eyes. The Bug-eye had a Mechanical fuel pump, whereas my MG and Rover had a Electric fuel pump.

CIS and Digi's have fuel that is being constantly re-cycled back to the tank.  The 4 second prime on key on helps to prevent vapor lock.

I would verify that all your fuel lines are shielded, once they leave the body. and start their way over the engine.

davearnill said

Hi nedrager. I’ve had a look at that pump and it looks very interesting,  as it’s a suction type it can be mounted in the engine bay instead of next to the fuel tank, much easier.

What filter are you running and did you fit the safety cut off relay too? Cheers

I'm running a Malpassi FIlter King with a glass bowl. I don't have a safety cut out installed… getting ready to swap over to fuel injection so no point now.

Hi Briano

I was thinking about insulating the fuel lines somehow to help keep the heat away, at the moment there pretty standard I think and are very warm to the touch, I guess a lot of heat comes from the mech pump though so not sure if I can do anything there.

I took the golf out today for a 20 miler or so with no running issues at all,  on returning home I left it running on the drive for around 10mins to see if it cut out again, no cutting out but lots of bubbles and percolation going back down the fuel return line, I’m gonna fit some clear fuel pipe between the swirl pot and carb to see if does the same on the carb line.

I though the swirl pot also helped with fuel vapour issues as well as keeping a steady supply to the carb.

I managed to buy a new top card for the rad last year but am still missing the side cards, I’m thinking of making some when I get around to it, should also help with the heat.

im gonna add some pics and if possible a video of the percolation issue I had today, thanks for the info, learn something new everyday with these old cars.

Hi nedrager

I like the mounting position you chose for the pump, I was thinking of mounting one on the inner wing as its a bit cooler there, good shout for the filter too, I’m gonna persevere a little longer with the mech pump setup as the car has done 110k on a mech pump plus vw obviously invested a lot of development time on the fuel system, end of the day though I just need a reliable car so still might switch.

are you going injection for power or reliability? I guess you’ll most likely get a good dose of both.

I would change the plastic fuel return pipe with those joints to 1 section of rubber fuel hose .

Try adding a longer length of fuel hose to the fuel filler so it's further away from the heat of the engine and exhaust.

What's going on with your oil dip stick holder ?
Replacements are readily available for little money and you know the oil level is correct.

Hi Mark

good shout on the fuel lines, I’ll look at replacing those and reposition slightly, I already have new dip stick holder, ready to fit when I get a bit of time, thanks for the advice.

davearnill said

Hi nedrager

I like the mounting position you chose for the pump, I was thinking of mounting one on the inner wing as its a bit cooler there, good shout for the filter too, I’m gonna persevere a little longer with the mech pump setup as the car has done 110k on a mech pump plus vw obviously invested a lot of development time on the fuel system, end of the day though I just need a reliable car so still might switch.

are you going injection for power or reliability? I guess you’ll most likely get a good dose of both.

The pump itself is mounted on top of the breather on the back of the engine, below the fuel filter. I'm going injection for consistency really. I made 150bhp from a 1.4, currently have a hybrid 1.6 installed. The next one will a 1.4, JE pistons, forged rods, Schrick cams and a lot more rpm… I've never done throttle bodies before so it's a personal challenge as well because I tune my own stuff.