How to test a manual fuel pump

[Cakeman2253]

Is there any way to test a manual fuel pump? Or at least I think that’s the problem with the dodge 318.
I have not started the blue whale in about a 1-1/2 months. Normally when it hasn’t been started in a month, I pour a little gas in the carb and she will fire right up. Well this time no start. It will run when I pour gas in the carb until it burn off. I have tried the several times with a mason jar. I pulled the gas line going into the carb and cranked the motor, but nothing comes out of the fuel line. Filter is clean, as it’s a clear one and also no gas in the filter. If I suck on the hose, yummy, I can get some gas out the line.  I didn’t really want to start on the main fuel line, unless someone has a better way to suck gas through a line to make sure nothing is stuck in the line or blow on it and blow the gunk back into the tank. I don’t want to drop the tank, but for some reason it’s not getting fuel. I don’t believe there is a pump or filter in the tank and I can trace the line back to the tank and no inline pump.

I did pull the fuel pump (it was sunny and yard work done, why not lay under the MH), wow that has to be the longest pump arm I have seen; it seems to pump and makes a sucking noise. Should I replace, since they are only about $17? Maybe cheap insurance since it’s off and most likely the original 30 year old pump? I don’t want to go electric if I don’t have to.

I have about ¼ tank of gas, could that be too little for the pick up line?

Any thoughts?

[fgutie35]

I would disconect fuel line from carb. and put in a balloon. Then crank the engine. If you don't get gas, at least you should get air, which would indicate that the pump is sucking and pumping at it should and that the seals are OK. If you don't get air, then there is a broken seal and the pump is not suctioning properly.

[DaveVA78Chieftain]

I have never tried the ballon trick.  I always use a fuel pressure tool gauge to test.  I have used the brake line hand pump suction setup to prime the fuel line before.  Fuel goes in the container rather than the pump that way.

Dave

[Cakeman2253]

Well it was the fuel pump. I now have a pre filter and an after filter. By the way. The part was $17.99 on line at advanced auto, but $24.99 in-store. When I asked why cheaper, they stated parts are always cheaper on line. I had brought the print out and they price matched. Good to know in the future.
Thanks once again.

[jedwards]

Question relating to ypur problem, I have replaced all rubber fuel lines, blew out all metal ones, dropped tank and had it cleaned, replaced the pum, but stil am not getting gas to carb...any ideas?

[DRMousseau]

mmmm,... from the line closest to tank, jus line and tank,... can you blow bubbles into the fuel??? Can you suck fuel from tank (yuck!) If so, then continue. (IF NOT,... then add fuel to tank! Lol! Been there,... done that!)


Add the next component (usually a filter), and repeat. Remember, SOME filters may have a one way check valve,... make SURE flow is in proper direction for filter. If you have such a filter, you'll only be able pass air or fuel one way. If you can get fuel thru this component,... then add the next line or component and repeat.


Somewhere, you'll reach the fuel pump. Again, there is most likely a check valve to keep fuel from flowing back to the tank. So when you connect the last line to the fuel pump, make sure you have fuel pump hoses connected properly.This last line will reach the carburetor as your last component,.. and should be able to suck fuel right up to the hose end! IF you cannot suck fuel THRU the last line from the fuel pump,... then double check your pump installation. Hopefully you didn't damage anything in a faulty installation. And, it can always be a faulty pump, or rather pump assembly. If you DO get fuel thru all this,... then activate pump a few moments. You should have fuel coming out the line your gonna connect to the carb.


IF NOT,... again, check your new pump installation. Remove the pump assy if necessary, and activate by hand. If there's no activity at the hose end, then you might have a pump diaphram issue. Could be damaged, could be nothing more than loose assembly screws. But if this gets you some fuel at the hose end, THEN you might have the wrong pump for the particular engine. Actually, the wrong activating arm for the particular engine application.


Loose clamps, air leaks, plugged fittings, wrong pumps, broken parts, and other issues will usually be easily found and diagnosed with this procedure. And you might have ANY of those issues,... it sounds like a whole new system!!!


 

[jedwards]

checked all filters, ran threw and checked every connection and hose clamp, all are good, however every line is still dry, I do remember when I put the pump in that it went in pretty easy...way easier then the old ford ones that I have replaced, is it possinle that it didn't line up right? I have never had this issue before..im so frustrated...

[jedwards]

I will pull pump tomorrow and see if it drams fuel when pumping by hand, I think I just need to walk away for the rest of the night with this frustration, thank you for the advice, hopefully I return tomorrow with good news.

[DRMousseau]

ALWAYS good to walk away sometimes,... clear your head, think about a bit, freshen the coffee, or whatever.


But your SURE you have an adequate fuel level in the tank, right??? That's been the only real issue I've had,... my figures said I had nearly 10gal left in tank. But everything else said I either had a pump issue or ran outa gas. Well, I DID have nearly 10gal left, but I guess I have a short drop in the tank. Added a few gallons and everything was fine.


But pulling that pump tomorrow, and trying it by hand will probably verify what you suspect,.... installation issues!

[sasktrini]

You mentioned the long pump arm in your initial post… maybe it's not seated properly.

[jeno]

this is just a thought but is it possible the fuel lines on the pump are reversed

[jedwards]

tank is full of gas, double checked all lines connections, hoses, clamps, and made sure everything is to be flowing right, its all good, Im pon my way now to pull the pump to see what happens not that im not so frustrated with it..lol...thank for all the advice everyon..we will see how this goes..

[jeno]

good luck

[jedwards]

 ... so I got the ole beast started!!!!! after 3......yes a total of 3 fuel pumps from oriellys that where bad, went over to Napa, got a pump threw er in and bam!!!! I've got gas. My other question though...for these older ones should I put 2 filters on or will one do it...and where is the recommended placement, I didn't have any when I got it, I currently have one, after tank before the split to generator/440 engine. She seems to be missing a little, put new plugs in that where supposedly gaped right, will have to check those out next...very happy this thing started...got huge cheers from everyone when she fired over to...lol...thank again everyone

[rustyzman]

     I had similar issues with O'reilly pumps.  Their Precision brand pump is trouble.  Precision made nice U joints back in the day, but they appear to have succumbed to the Good Name Brand put on Poor Quality parts fate that so many other solid company names have.  I bought one locally due to a leaky original and time frame issues, installed it and immediately a horrendous knocking noise.  Removed it, found the pump arm now had lots of free play.  The casting was poorly machined and the return spring for the pump would not maintain pressure on the lever arm.  Brought it back, got a second one and checked it right at the counter.  Same problem.  Asked for a refund and had to argue with the manager to get it because it had been "installed" and therefore could only be warrantied for a new one.  I explained that when two are bad straight out of the box, a third try was not a prudent move.  Finally got him to give me my money back.
      Professionally I had good luck with Airtex.  I don't recall having a faulty one or an early failure and have replaced more fuel pumps than I can remember.  Airtex makes a mechanical pump for these vehicles, so I bought two of those at rockauto instead and have had no problems at all.  Had to wait a few days, but worth it.  Having a spare is not a bad idea.  Real bummer to be stuck somewhere over a part that is under $20.
     Back when we were in the Napa Auto Care Center group, we sold lots of Napa pumps.  At the time their fuel and water pumps were Airtex reboxes.  Napa sells good stuff.
     Just my $.02 in case it helps.
     

[Froggy1936]

Having a spare part I have found will almost always guarantee you will never need it , I carry a few spares Alternator, starter, hoses ,belts, bulbs etc All failures have been other stuff ! Frank

[DRMousseau]

Thought I had a problem yesterday, with the rear fuel supply. I KNOW there's adequate fuel, and new electric pump seems to work fine. Still, I could only get fuel to the carb from the main tank system and not the rear. Turned out,... I was forgetting to switch the tank lever beside the seat!!!

[joanfenn]

May all your problems be so easy to  solve.

[tiinytina]

All the spare parts, fluids, petroleum products etc knowledge learned here which I carry have come in handy to very many people... along the way.... The tools to replace all the above.. have... to date.. been more important to getting myself down the road.. LOL... yea and having many here on speed dial!

Tina