fuel pump

[Stephen115]

I got a fuel pump off of ebay, its a pulse one. I have it mounted on a slant, would this cause it to not work correctly? it only pumps fuel if you hold the gas tank up. if I put it under the steering like I want it to be, it won't pump it up towards the fuel pump.

thanks
SJ

 

[OzFab]

If it's like any other fuel pump, it only feeds under pressure after the pump, the feed to the pump is still a gravity feed so the pump inlet must be below the tank pickup.

Having it mounted on an angle will add to this scenario; mount it flat, as low as possible

 

[Doc Sprocket]

Just thinking out loud here- it might be okay after you've got the system primed. By tipping the kart, using a vacuum pump, marine primer bulb, or similar method, get the fuel to the carb. With the line primed and the carb bowl filled, start the engine and see whether it will continue to pump. I suspect it will. Make sure pulse fittings and hose are sealed up tight with hose clamps- you do not want any air leaks.

 

[jandj]

If it's like any other fuel pump, it only feeds under pressure after the pump, the feed to the pump is still a gravity feed so the pump inlet must be below the tank pickup.

Having it mounted on an angle will add to this scenario; mount it flat, as low as possible

I have a floor tank with the petcock at the bottom and a fuel pump on the plate on top of my clone, so you can mount your pump above the tank pickup, but as toystory said, you'll need to fill the carb bowl and manually (vacuum) feed fuel to the pump to get it started the first time. After that, vacuum from the pulse fitting will pull the fuel into the pump as long as you don't open the line and "lose the prime". You can also install a 1-way check valve in your feed line to help hold fuel in the line.

 

[OzFab]

Valid point guys. I did say "if"

 

[Stephen115]

filled the bowl and its still not pulling enough fuel

 

[jandj]

I know it sounds like a "duh" comment, but make sure your lines are hooked to the correct port on the pump...it's an easy mistake to make.
Assuming they are correct, if it was me I'd:
Make sure the line from the tank to the pump is completely full.
Make sure the line from the pump to the carb is completely full.
Make sure the carb bowl is full.
Give it a very small shot of instant start. VERY SMALL. Others may disagree here, the key is to not over-do it.
It should hit and run long enough for the pulse line to pull fuel through the pump and let the motor run on it's own from the fuel from the tank

 

[Stephen115]

I know it sounds like a "duh" comment, but make sure your lines are hooked to the correct port on the pump...it's an easy mistake to make.
Assuming they are correct, if it was me I'd:
Make sure the line from the tank to the pump is completely full.
Make sure the line from the pump to the carb is completely full.
Make sure the carb bowl is full.
Give it a very small shot of instant start. VERY SMALL. Others may disagree here, the key is to not over-do it.
It should hit and run long enough for the pulse line to pull fuel through the pump and let the motor run on it's own from the fuel from the tank

I think I have it hooked up right. I mean it does pump fuel if you hold the tank up high. there are arrows, i'm assuming they go from the tank towards the carb?

 

[anderkart]

Yes arrows should be signifying flow from tank to carb.

Pulse pumps work fine mounted on a slant, flat or even upside down. They draw much better than they push, so mounting the pump up-higher than the tank, and as close to the carb as possible is the preferred location. Pulse pumps can draw fuel uphill 2 or 3 feet, no problem.

I installed a marine primer bulb between my tank and pulse pump inlet... Just takes a few squeezes to bleed the lines, pump and fill the float bowl. You might try that but I think you have some other issue here:

Where are you connecting your pulse-line to the engine? (got pics?)

What brand/model pulse pump did you get? (got pics or a link to it?)

Do you have some type of hose clamp on both ends, of all 3 lines?

Do you have a fuel filter? (is it plugged or possibly installed backwards?)

Does fuel flow freely from your tank?

Will the engine start/run for a few seconds when you prime it?

When you know your float-bowl is dry: Try blowing into the fuel line running to your carb. (does air blow through easily or does it seem all plugged up?)

 

[Doc Sprocket]

Just takes a few sneezes to bleed

Then, you need an ear, nose, and throat specialist!

I'm sorry- I absolutely could NOT resist! When I suggested the primer bulb, I didn't actually think anybody used one! Good to hear.

 

[anderkart]

Then, you need an ear, nose, and throat specialist!

I'm sorry- I absolutely could NOT resist! When I suggested the primer bulb, I didn't actually think anybody used one! Good to hear.

Lol, yes you had a very good idea there, primer bulbs rule! Hey Bubb, here's a pic of my bulb:

I had problems with too much fuel pressure overpowering my carbs needle and seat, so I installed a return system back to the tank. Its got a Briggs in-line fuel shut off valve so I can meter how much returns.

 

[Doc Sprocket]

Ahh- the poor man's regulator! Cool!

 

[Stephen115]

Yes arrows should be signifying flow from tank to carb.

Pulse pumps work fine mounted on a slant, flat or even upside down. They draw much better than they push, so mounting the pump up-higher than the tank, and as close to the carb as possible is the preferred location. Pulse pumps can draw fuel uphill 2 or 3 feet, no problem.

I installed a marine primer bulb between my tank and pulse pump inlet... Just takes a few squeezes to bleed the lines, pump and fill the float bowl. You might try that but I think you have some other issue here:

Where are you connecting your pulse-line to the engine? (got pics?)

What brand/model pulse pump did you get? (got pics or a link to it?)

Do you have some type of hose clamp on both ends, of all 3 lines?

Do you have a fuel filter? (is it plugged or possibly installed backwards?)

Does fuel flow freely from your tank?

Will the engine start/run for a few seconds when you prime it?

When you know your float-bowl is dry: Try blowing into the fuel line running to your carb. (does air blow through easily or does it seem all plugged up?)

I'm connecting it to the valve cover. agk said it works.

Its an ebay pump, got it for $8

I have hose clamps on all the ends.

I don't have a fuel filter but I should get one.

fuel does flow freely from the tank.

if I hold the tank up fuel will flow enough to get the engine started but when it sits for a minute it doesn't push enough fuel.

Once I get the engine started I can see fuel being pumped into the carb that is in the lines. but I can't see it pumping it into the pump unless I hold the tank up

 

[Stephen115]

where can I get a primer bulb?

 

[anderkart]

Sounds like your pump might be defective or just a low quality brand/model that doesn't have very much power.

Another possibility is your pulse line is flexing in-out, resulting in a weak pulse signal to the pump. You might try using a 1/4" automotive fuel line for your pulse line.

You didnt answer my last question, are you sure your carbs fuel-inlet passage/needle and seat valve isnt just dirty/plugged/suck-closed?

You can buy a 1/4" marine primer bulb at most anyplace that sells boats and boat engine parts.
Or, order one online here:--> http://www.google.com/search?source...T4GZAZ_enUS369US369&q=1/4"+marine+primer+bulb

 

[jandj]

Sounds like your pump might be defective or just a low quality brand/model that doesn't have very much power.

I'd suspect that may well be the case.
i've got a 10 year old Walbro square pump that still works fine and a year old Mikuni lookalike that didn't work for squat from day one.
You get what you pay for.
I knew better and bought it anyway.
Anyone want a bargain priced fuel pump?

 

[Stephen115]

I'm sure my carb is not junked up. I just did a clean on it

 

[jandj]

You say that if you hold the tank up (using gravity to feed the pump) it'll start and run but if you let it sit and try to restart it won't push enough fuel.
I'm assuming (yeah, I know!) when you say "push" you mean push fuel from the pump to the carb and when you say "let it sit" you mean returning the tank to it's normal level.
If the line from the tank to the pump remains full but you can't get fuel from the pump to the carb, it sounds like a weak pump.
If your carb bowl is full it should start no matter where the tank is and even if there's no fuel flowing to it, it should run until what's in the bowl is used - that should be plenty of time for the pump to "pick up the prime" and push more fuel to the carb.
Once you get it running let it run for a minute or two to make sure all your lines are full.
When you shut it off, close the fitting on the tank - that will hold fuel in the line to the pump.
At this point you should have all your lines and the carb full and the fuel in the line from the tank to the pump should stay full as it can't drain back into the tank with the fitting closed.
If you try to restart it and fuel won't go from the pump to the carb, I'd personally spend a few bucks and get a Walbro or Mikuni pump. It'll cost more than the one you have but it sounds to me like the one you have ain't gettin' the job done.
Unsaid in all this is I'm also assuming that there are no leaks in the pulse line from the valve cover to the pump - if there are, it doesn't matter what kind of pulse pump you have, it's not going to work.

 

[Stephen115]

You say that if you hold the tank up (using gravity to feed the pump) it'll start and run but if you let it sit and try to restart it won't push enough fuel.
I'm assuming (yeah, I know!) when you say "push" you mean push fuel from the pump to the carb and when you say "let it sit" you mean returning the tank to it's normal level.
If the line from the tank to the pump remains full but you can't get fuel from the pump to the carb, it sounds like a weak pump.
If your carb bowl is full it should start no matter where the tank is and even if there's no fuel flowing to it, it should run until what's in the bowl is used - that should be plenty of time for the pump to "pick up the prime" and push more fuel to the carb.
Once you get it running let it run for a minute or two to make sure all your lines are full.
When you shut it off, close the fitting on the tank - that will hold fuel in the line to the pump.
At this point you should have all your lines and the carb full and the fuel in the line from the tank to the pump should stay full as it can't drain back into the tank with the fitting closed.
If you try to restart it and fuel won't go from the pump to the carb, I'd personally spend a few bucks and get a Walbro or Mikuni pump. It'll cost more than the one you have but it sounds to me like the one you have ain't gettin' the job done.
Unsaid in all this is I'm also assuming that there are no leaks in the pulse line from the valve cover to the pump - if there are, it doesn't matter what kind of pulse pump you have, it's not going to work.

it starts if the bowl is full. I'll check my pulse line.

 

[Stephen115]

I probably just need a better pump