Fuel pump,/flow question, 239 8BA
Post Fiend
Joined: May 2008
Posts: 7,641
Likes: 21
From: Poway, Ca.
If you want to use the mechanical pump to drive on and the electric to prime and boost at start, all you would have to do is run the parallel lines as Ross suggested (or just plumb the electric pump in a paralell by pass to the main line going to the carb), then put a floor mounted foot start switch on the line powering the electric pump.
Turn on the key, step on the foot switch to activate the electric pump, then push the start button. Truck starts, take your foot off the foot switch - drive to the beach on the mechanical pump!!
PS This would also be great if you run out of gas and need to get fuel up to the carb in a hurry without Grinding on the starter.
Like this:
Turn on the key, step on the foot switch to activate the electric pump, then push the start button. Truck starts, take your foot off the foot switch - drive to the beach on the mechanical pump!!
PS This would also be great if you run out of gas and need to get fuel up to the carb in a hurry without Grinding on the starter.
Like this:
Post Fiend
Joined: May 2008
Posts: 7,641
Likes: 21
From: Poway, Ca.
With the foot start switch, it's spring loaded and will shut the electric pump off when you take foot pressure off of it. This avoids mistakingly leaving the pump on. I think they are $10 at AutoZone!
Mountain Pass
Joined: May 2004
Posts: 145
Likes: 16
From: Jonesborough, TN
If your only using for priming just a toggle switch mounted under the dash is all you need. It is noisy enough to remind you to turn it off.
The PO mounted the toggle switch in the dash which bugged me every time I looked at it so I replaced the toggle switch with a vintage looking indicator light hooked to the fuel pump and found an empty hole in the bottom edge of the dash and mounted the switch facing down (had to ream out the hole a little). it is over by the starter button so I flip it on to prime and switch it off when I reach over to hit the starter button.
The PO mounted the toggle switch in the dash which bugged me every time I looked at it so I replaced the toggle switch with a vintage looking indicator light hooked to the fuel pump and found an empty hole in the bottom edge of the dash and mounted the switch facing down (had to ream out the hole a little). it is over by the starter button so I flip it on to prime and switch it off when I reach over to hit the starter button.
Elder User
Joined: Nov 2008
Posts: 915
Likes: 1
From: Gunbarrel, Co.
A bit late to the party, but this is how I isolated the fuel pump. Placed it as far behind the cab as I could. Next made a bracket with three rubber mount I had left over from one of my bike builds. These thing are normally used to mount the battery box or oil tank to the frame. They have 1/4-20 thread studs on both ends. So mounted the bracket that came with the pump to the new bracket via the rubber mounts, as in the picture. I would not say it's whisper quite, but definitely an improvement.
Thread Starter
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Senior User
Joined: Jun 2008
Posts: 347
Likes: 0
From: Wilmington Delaware
UPDATE
I got the seperate fuel feed to the mechanical pump as per Ross's drawing but could get no fuel to it. Glass bowl got no fuel. Motor fired right up with the electric pump so I cut power to the electric pump via a temp toggle switch. I was hoping the mech pump wold start to draw/prime but the carb ran out of fuel first. Tried it 3X's but no fuel was getting to the mech pump.
I disconected the line in and out of the mech pump and ran a couple long hose pieces to the inlet and out side, started it up but could not feel or hear any draw. I was giong to put some fuel in a can and run the hoses into it to test but I dont think Its pulling. I am pretty sure I got the pump on the push rod OK. Last year I measured the rod and did a eye ball check of the rod lift to see if the cam lobe was worn to much to push the rod but it looked to check out ok.
The little cap on the rocker arm did not seem to be as beefy as what was on the old pump, Can the rocker arm slip off the rod if the cap is bad or goes bad?. Any way.... any thoughts?
I am going to pull the pump later and see whats up. It had good draw when I bench tested it
I disconected the line in and out of the mech pump and ran a couple long hose pieces to the inlet and out side, started it up but could not feel or hear any draw. I was giong to put some fuel in a can and run the hoses into it to test but I dont think Its pulling. I am pretty sure I got the pump on the push rod OK. Last year I measured the rod and did a eye ball check of the rod lift to see if the cam lobe was worn to much to push the rod but it looked to check out ok.
The little cap on the rocker arm did not seem to be as beefy as what was on the old pump, Can the rocker arm slip off the rod if the cap is bad or goes bad?. Any way.... any thoughts?
I am going to pull the pump later and see whats up. It had good draw when I bench tested it
Fleet Owner
Joined: Jul 2004
Posts: 27,294
Likes: 1,055
From: NM
Has the gas tank been really cleaned out, and the outlet valve cleaned? Is the mech pump pretty new? It boils down to either the mech pump isn't working, or it can't lift gas by suction up to the top of the engine. Your description of the electric pump thumping loudly makes me suspect it is also having trouble drawing fuel, and the only common thing is the suction out of the tank. Can you connect up a boat tank to the suction line, right where it would connect to the tank? If everything starts working normally, you'll know it's the tank and not the lines or pump. I don't remember if you've replaced or cleaned all the lines? That is critical!
As far as the cap on the pump, with a fresh pump, there isn't much for the cap to do. It helps keep the pump arm on the pushrod when the arm linkage gets old and sloppy. Try loosening the pump stand bolts (at the intake) about 1/4", turn the engine over by hand and watch to see if the pump stand moves up and down a good amount.
As far as the cap on the pump, with a fresh pump, there isn't much for the cap to do. It helps keep the pump arm on the pushrod when the arm linkage gets old and sloppy. Try loosening the pump stand bolts (at the intake) about 1/4", turn the engine over by hand and watch to see if the pump stand moves up and down a good amount.
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Laughing Gas
Joined: Nov 2008
Posts: 914
Likes: 51
From: SW Missouri
Most of the time when someone "bench test" a mechanical pump they move the lever much further than the pump rod would move it. The pump rod in a flathead moved the arm very little. Also as a switch for your electric pump, a push button momentary switch like a starter button switch works well as does a momentary toggle switch. Both have to be held down to make the electric pump work and as soon as released the mechanical pump takes over. Your mechanical pump is very sensitive to air leaks and if any connection before the pump is leaking the slightest amount it will not pump fuel.
Good luck
Larry
Good luck
Larry
Thread Starter
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Senior User
Joined: Jun 2008
Posts: 347
Likes: 0
From: Wilmington Delaware
The tank is new, as are all the lines. No long rubber connections (this time ).
The pump is brand new from NAPA.Before I pull the pump off I will try unbolting the stand a bit as Ross suggest and then I will try to isolate the mech pump with a small tank to see if it pulls. Yea,...the bench test always pushes the pump way beyond what the push rod moves the arm. I will double check the connections ahead of the pump also. Thanks
The pump is brand new from NAPA.Before I pull the pump off I will try unbolting the stand a bit as Ross suggest and then I will try to isolate the mech pump with a small tank to see if it pulls. Yea,...the bench test always pushes the pump way beyond what the push rod moves the arm. I will double check the connections ahead of the pump also. Thanks
Thread Starter
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Senior User
Joined: Jun 2008
Posts: 347
Likes: 0
From: Wilmington Delaware
another update
I loosened up the pump stand bolts and turned it over a bit and noticed no real movement. Tightened up the bolts and loosened the pump/stand bolts,
There seemed to be tension, but it didnt move any when I turned it over a few times.
I put the inlet hose in to a can of gas and cranked it but no go.
I removed the pump and observed the rod while cranking and it had decent movement up and down however it has a bit of wobble to it. I could could move it around not quite a 1/4 inch with my finger. ( hence the rod cap,... I guess )
I took the pump to the bench and I put the inlet hose into a can of gas and manually moved the pump arm and it drew fuel right up.
I put a block off plate on the pump stand and will get back to it later because it is HOT AS HELL in my garage.
Any thoughts,
There seemed to be tension, but it didnt move any when I turned it over a few times.
I put the inlet hose in to a can of gas and cranked it but no go.
I removed the pump and observed the rod while cranking and it had decent movement up and down however it has a bit of wobble to it. I could could move it around not quite a 1/4 inch with my finger. ( hence the rod cap,... I guess )
I took the pump to the bench and I put the inlet hose into a can of gas and manually moved the pump arm and it drew fuel right up.
I put a block off plate on the pump stand and will get back to it later because it is HOT AS HELL in my garage.
Any thoughts,
Fleet Owner
Joined: Jul 2004
Posts: 27,294
Likes: 1,055
From: NM
The pushrod shouldn't wobble that much, your pushrod bushing must be worn. Replacing the bushing is something I've never done myself, but I've seen the process described and it's not that bad. Personally, I'd spend some time getting the electric pump quiet, use that for now and next winter work on the mech pump -- it's driving time!!
PS -- Van Pelt sells the pushrod bushing for $5. On this page he lists the fuel pump pushrod for 8BA's with cast iron intakes as 10.064" long -- did you measure yours?
http://www.vanpeltsales.com/FH_web/e...prices-pg3.htm
PS -- Van Pelt sells the pushrod bushing for $5. On this page he lists the fuel pump pushrod for 8BA's with cast iron intakes as 10.064" long -- did you measure yours?
http://www.vanpeltsales.com/FH_web/e...prices-pg3.htm
Fleet Owner
Joined: Jul 2004
Posts: 27,294
Likes: 1,055
From: NM
Early engines used ones that were MUCH shorter, hard to mistake them, they are like 3" shorter -- see the Van Pelt page above