what is killing my fuel pumps?
08-27-2014, 09:00 PM
#11
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Dead Head electric pumps are a flawed design from the get go. The pump can overheat with just the key on if there is no oil pressure switch safety. Electric pumps work well with return style fuel logs or regulators as they are able to keep pumping cool fuel. I would not use them otherwise.
Soumds like you would have gen 4 blocks in a 78. Go with mechanical pumps and relax.
Soumds like you would have gen 4 blocks in a 78. Go with mechanical pumps and relax.
08-28-2014, 12:48 AM
#12
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I think you all are reading more into it than what it simply is, and that is mount the pump no higher than a couple inches at the most higher than the pickup coming out of the tank, at near empty you are still pulling fuel 12 to 18 inches up.
I would not be so adamant about trying this first if the cure I was suggested had not worked so clearly after it was completed by me after beating my head against the wall for 6 months and the professional generator installer suggesting the tank pickup was bad.
The generator was mounted in a large sailboat I was captaining by professional installers who fit 100 pounds of chit in a 10 pound bag very impressively. But after going thru 3 pumps they blamed the fuel pickups in the tank and walked so I took the problem over.
Thank god for friends in hi places who are older and been around the block a few times and has been building and running airboats for 30 years.
Almost was ready to cut the bunks up and remove the tanks before he informed me of this technicality with fuel pumps.
I would not be so adamant about trying this first if the cure I was suggested had not worked so clearly after it was completed by me after beating my head against the wall for 6 months and the professional generator installer suggesting the tank pickup was bad.
The generator was mounted in a large sailboat I was captaining by professional installers who fit 100 pounds of chit in a 10 pound bag very impressively. But after going thru 3 pumps they blamed the fuel pickups in the tank and walked so I took the problem over.
Thank god for friends in hi places who are older and been around the block a few times and has been building and running airboats for 30 years.
Almost was ready to cut the bunks up and remove the tanks before he informed me of this technicality with fuel pumps.
09-02-2014, 01:02 PM
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Dead Head electric pumps are a flawed design from the get go. The pump can overheat with just the key on if there is no oil pressure switch safety. Electric pumps work well with return style fuel logs or regulators as they are able to keep pumping cool fuel. I would not use them otherwise.
Soumds like you would have gen 4 blocks in a 78. Go with mechanical pumps and relax.
Soumds like you would have gen 4 blocks in a 78. Go with mechanical pumps and relax.
I've got gen VI 502's in it, no way to use a mechanical pump, and it's wired with oil pressure switches so the pump won't turn on until the engine is turning over.
since making this post, brand new pump # 2 has died. Pulled it apart because I was pissed that a fuel pump with 5 min of run time could die. The pump head itself looked fine, and when I hooked it to a direct 12v source, nothing. Hit it a few times to see if it would start spinning, still nothing. separated the pump from the motor and had to spin the shaft from the motor to get it turning. Let it run for about 30 sec, and turned it on and off 3 times. Set it down on my bench and answered a phone call. came back to it about 5 min later and tried again; it was already seized again. This time hitting it with a screw driver got it going.
I don't think being above the tank is hurting it, as soon as the good pump gets power it's almost instantly showing fuel pressure at the carb. The pumps are also mounted a little lower than the fuel filter/water separator.
I've checked the wiring, and sitting with the key off there is 0v going to the pump, key on engine off, 0v, key on engine cranking was 11v and once the engine started the reading was 13v
I'm hoping i just got a bad batch of carter pumps. The replacement on my port motor is still working after sitting a week and about 6 min of run time, which is more than the pump before it. I just don't see how a total of 5 min runtime (no longer than 1 min consecutive) with fuel pumping through it could kill a good fuel pump if it wasn't already flawed.
Last edited by performancems; 09-02-2014 at 01:05 PM.
09-02-2014, 01:20 PM
#16
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Sorry to thread jack, but I'll post my question here.
I'm sorting out a new-to-me 502/502hp 850 carb package, and seem to be missing about ~100hp. I'm running a Holley Red electric fuel pump with 67gph @7psi or 98gph free flow. That should be adequate for this package, yes?
Thanks!
I'm sorting out a new-to-me 502/502hp 850 carb package, and seem to be missing about ~100hp. I'm running a Holley Red electric fuel pump with 67gph @7psi or 98gph free flow. That should be adequate for this package, yes?
Thanks!
09-02-2014, 01:49 PM
#17
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Sorry to thread jack, but I'll post my question here.
I'm sorting out a new-to-me 502/502hp 850 carb package, and seem to be missing about ~100hp. I'm running a Holley Red electric fuel pump with 67gph @7psi or 98gph free flow. That should be adequate for this package, yes?
Thanks!
I'm sorting out a new-to-me 502/502hp 850 carb package, and seem to be missing about ~100hp. I'm running a Holley Red electric fuel pump with 67gph @7psi or 98gph free flow. That should be adequate for this package, yes?
Thanks!
09-02-2014, 01:51 PM
#18
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I've got gen VI 502's in it, no way to use a mechanical pump, and it's wired with oil pressure switches so the pump won't turn on until the engine is turning over.
since making this post, brand new pump # 2 has died. Pulled it apart because I was pissed that a fuel pump with 5 min of run time could die. The pump head itself looked fine, and when I hooked it to a direct 12v source, nothing. Hit it a few times to see if it would start spinning, still nothing. separated the pump from the motor and had to spin the shaft from the motor to get it turning. Let it run for about 30 sec, and turned it on and off 3 times. Set it down on my bench and answered a phone call. came back to it about 5 min later and tried again; it was already seized again. This time hitting it with a screw driver got it going.
I don't think being above the tank is hurting it, as soon as the good pump gets power it's almost instantly showing fuel pressure at the carb. The pumps are also mounted a little lower than the fuel filter/water separator.
I've checked the wiring, and sitting with the key off there is 0v going to the pump, key on engine off, 0v, key on engine cranking was 11v and once the engine started the reading was 13v
I'm hoping i just got a bad batch of carter pumps. The replacement on my port motor is still working after sitting a week and about 6 min of run time, which is more than the pump before it. I just don't see how a total of 5 min runtime (no longer than 1 min consecutive) with fuel pumping through it could kill a good fuel pump if it wasn't already flawed.
since making this post, brand new pump # 2 has died. Pulled it apart because I was pissed that a fuel pump with 5 min of run time could die. The pump head itself looked fine, and when I hooked it to a direct 12v source, nothing. Hit it a few times to see if it would start spinning, still nothing. separated the pump from the motor and had to spin the shaft from the motor to get it turning. Let it run for about 30 sec, and turned it on and off 3 times. Set it down on my bench and answered a phone call. came back to it about 5 min later and tried again; it was already seized again. This time hitting it with a screw driver got it going.
I don't think being above the tank is hurting it, as soon as the good pump gets power it's almost instantly showing fuel pressure at the carb. The pumps are also mounted a little lower than the fuel filter/water separator.
I've checked the wiring, and sitting with the key off there is 0v going to the pump, key on engine off, 0v, key on engine cranking was 11v and once the engine started the reading was 13v
I'm hoping i just got a bad batch of carter pumps. The replacement on my port motor is still working after sitting a week and about 6 min of run time, which is more than the pump before it. I just don't see how a total of 5 min runtime (no longer than 1 min consecutive) with fuel pumping through it could kill a good fuel pump if it wasn't already flawed.
09-10-2014, 02:28 PM
#20
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The issue with the carter is that they want the gas flowing THROUGH the motor itself for cooling. 4 out of 5 pumps I went through weren't letting the gas go through the pump head and into the electric motor, so after running dry for a few minutes, they seized once turned off. ****ty design, and I would never want gas flowing through the electric motor . The holley ones don't want any gas to enter the motor so i think I should be fine now. FedEx tracking says they will be here tomorrow, so hopefully I'll be able to take the boat for its first ride this weekend!
