Fuel pump drive rod

I

Ianrhall

Senior Member
After much head scratching today I discovered the reason for the lack of fuel at my trucks carb.
The rod that should drive the pump does not go up and down! I have tried turning it round and also putting a long screwdriver in there, the cams going round but looks like the lobe has gone!
I have been using the truck until recently and the only symptom was difficulty in starting after being left for a couple of days.
Anyone had this? Thinking maybe I could use a 6 volt pump until I find another motor or have mine rebuilt
Which pump should I use?
Thanks
Ian
 
As to the electric pump, I installed an AIRTEX fuel pump. Part No. 3140415. Around $35.00. I mounted it near the fuel tank and put an on/off toggle switch under the dash. I do not run it all the time, just as needed and before starting if the car has been sitting for a long time such as in the spring. Search the archives on this site and there is a lot of info on this. If you are going to run it all the time the output pressure is vital. The site will have info on this.
 
Ian,
Be sure and get a low pressure pump. You should use a fuel pressure regulator at the carburetor. I use one set at about 2.5 lbs. of pressure and it works fine for me.
 
agree with sidevalve8ba. Use an electric pump and adjustable pressure regulator, will solve all your fuel delivery problems.
Some also add an inertia switch to the elect cct. This will shut off the pump in the event of a collision
 
If the camlobe is worn down you have to change the camshaft so its a bit of work involved.
If everything else is working fine i just put an electric fuel pump inline with the rest of the fuelsystem.
Make sure the fuelpump is ok if you keep it or theres a chance the fuel ends up in the engine oil.
 
i know the engine is fairly worn! This problem and also very low oil pressure but when it is running it actually performs quite well. If the pump gets me by for a while that would be a good result!!
Thinking of using the airtex pump and a low pressure Holley regulator, just need to find someone to ship to the uk.
Ian
 
My opinion is a Bendix used on Onan gen sets. Low pressure very quiet and only
supply's when needed. Little smaller than a soda can, that goes tic tic then stops.
 
I have never seen a fuelpump cam lobe worn to the point of no movement in the rod. The movement is very subtle, by design, and only elevates the rod about 1/4". Too, I don't see adequate performance one day changing to no performance the next day with regard to the pump lobe. I think another look is warranted. Be sure the rod movement is not compromised by crud build up and that it is free to float in the bushing.
 
A piston pump that is made for Engine bay mounting(low pressure) is perfect.
Just watch out so you dont get a bellowpump..they are still out there and dont like the modern gas to much.
And some of the pistonpumps has a capacitor across the points (cheapest is an electrolyte and they dont like reversed polarity !!)
Any pump with an electromagnet and points is worth checking for type of cap and replacing it with a foilcap for long and trouble free life.
 
I purchased my airtex 6 volt pump through rockauto.com it saved a couple dollars. Also I wired mine to my ignition and then to a toggle. This way if I forget to turn the pump off it will shut off when ignition is killed. Fuel regulator is a must also, it was flooding my carbs and causing to "overfill". I only run my pump after a long sit to aid in easy start.
Definitely take the advice of JWL above.
 
JWL said:
I have never seen a fuelpump cam lobe worn to the point of no movement in the rod. The movement is very subtle, by design, and only elevates the rod about 1/4". Too, I don't see adequate performance one day changing to no performance the next day with regard to the pump lobe. I think another look is warranted. Be sure the rod movement is not compromised by crud build up and that it is free to float in the bushing.
Click to expand...

Completely agree with this! But I've put the pushrod back in and also turned it round to ensure contact with the cam and it does not go up and down! Can feel that it is touching the cam as I rotate it
I have been having problems getting it started after standing but last time i used it it seemed ok
I will have another look shortly
Ian
 
Instead of using the pushrod to check for movement perhaps a smaller dia. rod could be used in the event that there may be something causing the original rod to hang up.
 
I know most don't agree with this but I run airtex low pressure pump (no manual) without a pressure regulator. I do have dual holly 2 barrel carbs and a pressure gauge located in engine bay and whenever checked it's always under 3 lbs. electric pump been on car for over 20 years as the previous owner had it installed.
 
maybe the rod itself has worn down some, here are some measurements to go by.
48-9400-A 8.872 CAST IRON INTAKE 8 7/8
48-9400-B 7.872 ALUMINUM INTAKE 7 7/8
 
A worn out fuel pump cam lobe is not unusual on a well used flathead.

Airtex electric without a regulator works for me.
 
The Airtex E8902 is a 6 volt low pressure pump. I don't use a pressure regulator, but I only use it for priming and vapor lock situations. Works very well. Pat
 
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