Holley Electric Fuel Pump Over Heating

[Pro-Tour69]

Hello to Everyone,

I am at my wits end with a problem that I simply cannot figure out and I am hoping someone can help. Here are the particulars.

- 76 Kindsvater
- ZZ502 stock motor
- Holley electric marine pump mounted on the right hand stringer just behind the motor
- Custom made aluminum tanks on each side underneath the deck
- Fuel outlet fitting is at the rear corner of each tank going into a y-block then plumbed into the fuel pump
- Each tank has its own vent
- Fuel pump is on its own separate circuit using the standard fuel pump relay kit from Summit/Jegs (recent upgrade)
- Fuel filter is a K&N type
- Fuel system is a dead head style
- Carb is the standard Holley 850 that came with the motor and fuel pressure is typical at 5.5-6.5
- Ignition system is MSD marine

The boat was restored back in the late 90's early 2000's and Brett Bayne actually did a restoration story in Hot Boat back in '03 and the boat ran great from then till about 5 years ago. Since then the fuel pump over heats and shuts down and obviously the motor stalls and I become stranded on the lake. I wait 20-30 minutes for it to cool down and she starts working again. The fuel pump circuit as originally wired was not setup on a separate relay circuit like it is now and when I first started to root cause the problem, the fuel pump circuit wires were melted so I thought awesome, this will fix the problem but it didn't. I have also replaced the fuel pump as well after redoing the fuel pump circuit but the problem did not get fixed.

I have checked both tank vents and no obstructions. the last thing left I am thinking to check is to pull the hose out of the tank and see if after sitting in fuel all those years at the bottom of the tank that maybe the tubing has weakened and when the pump sucks the fuel the tubing is actually compressing causing the pump to work that much harder to pull fuel.

Other than this last idea, I have no idea what else to check. This is where I need help.

Any suggestions would be greatly appreciated.

Thank you in advance,

Scott

[HB Vic]

Scott welcome to www.hotboat.com, nice boat!

I think you're saying the pump in on a relay now, correct? Something like a Bosch relay with the fuel pump DC wired close to the pump and battery, yes?

Do you have access to a DC clamp on ammeter by chance?

[hyperpasta]

The only thing I can see that is causing you a overheating issue is the Dead Head setup!
You'll fry that pump post haste if you keep running it this way. Now the tough part is how to return the fuel back the tanks???

You could return the excess fuel back to the tanks through the tank's vent fittings. Run a line from your "New" fuel pressure regulator to a T-fitting splitting the line back to each tank, of course you'd need a return style fuel pressure regulator too.
You will need to make sure the fuel tank fills are vented also to makeup for the loss of the tank vents.

The only other issue would be undersized fuel lines and fittings. 3/8 would be my minimum for the whole fuel system.

Other option is to purchase a Carter HP4600 it is internally regulated and internally retuns the fuel to prevent the dead Head situation. Pumps at 4.5-8psi and delivers around 100gph, use you existing fuel regulator.
https://www.summitracing.com/parts/crt-p4600hp


If you do a search on the web there have been a bunch of Holley fuel pump failures. Google is your friend.

Here's a link... https://www.google.com/search?q=holl...ilures&ie=&oe=

Happy Hunting....

Hello to Everyone,

I am at my wits end with a problem that I simply cannot figure out and I am hoping someone can help. Here are the particulars.

- 76 Kindsvater
- ZZ502 stock motor
- Holley electric marine pump mounted on the right hand stringer just behind the motor
- Custom made aluminum tanks on each side underneath the deck
- Fuel outlet fitting is at the rear corner of each tank going into a y-block then plumbed into the fuel pump
- Each tank has its own vent
- Fuel pump is on its own separate circuit using the standard fuel pump relay kit from Summit/Jegs (recent upgrade)
- Fuel filter is a K&N type
- Fuel system is a dead head style
- Carb is the standard Holley 850 that came with the motor and fuel pressure is typical at 5.5-6.5
- Ignition system is MSD marine

The boat was restored back in the late 90's early 2000's and Brett Bayne actually did a restoration story in Hot Boat back in '03 and the boat ran great from then till about 5 years ago. Since then the fuel pump over heats and shuts down and obviously the motor stalls and I become stranded on the lake. I wait 20-30 minutes for it to cool down and she starts working again. The fuel pump circuit as originally wired was not setup on a separate relay circuit like it is now and when I first started to root cause the problem, the fuel pump circuit wires were melted so I thought awesome, this will fix the problem but it didn't. I have also replaced the fuel pump as well after redoing the fuel pump circuit but the problem did not get fixed.

I have checked both tank vents and no obstructions. the last thing left I am thinking to check is to pull the hose out of the tank and see if after sitting in fuel all those years at the bottom of the tank that maybe the tubing has weakened and when the pump sucks the fuel the tubing is actually compressing causing the pump to work that much harder to pull fuel.

Other than this last idea, I have no idea what else to check. This is where I need help.

Any suggestions would be greatly appreciated.

Thank you in advance,

Scott

[HydroHaulic]

i had very similar problems...

[Pro-Tour69]

Hi Guys,

Thank you so far for the tips. The current setup for the fuel pump wiring is a dedicated circuit with relay. All the fuel lines are -8 braided hose as well. I have read on how the Holley electrics have failed and also read up on differences and advantages to redoing the plumbing to a return style system as mentioned as well. While changing those items or changing to the Carter pump which might be the easiest given the current situation, I am still wondering why after the first 10 years of trouble free use that now this problem has developed.

Is the consensus the dead head plumbing is really the root cause? My concern is if it was/is, why didn't this problem develop when the boat was first done and used that first year? I probably still should pull the fuel lines out of the tank to see if they have turned to mush as well. Changing to the return style plumbing and changing the in tank lines to and it still does it then I guess I will turn it into an early 4th of July spectacular.. (ok maybe kidding on the last point)

[Pro-Tour69]

One other question about the Carter pump. reading through the instructions online, it looks like the fuel lines are hook up just like a Holley. In from the tank and out to the carb/regulator. Hyperpasta, you said the pump is internally able to return fuel when not needed to eliminate the dead head scenario and so my question is it is able to do this without any additional fuel lines added to the system? I cannot find anything in the installation manual showing a return line so just replacing the pump would give me return line capability and I could leave all the current plumbing alone.

Would this be correct??

Thanks again.

[hyperpasta]

Ten Years!
I haven't had a marriage last that long, and I've been married twice!!
I'm thinking it's just time to plain old replace the pump. When you do go through the fuel system check filters, the float bowls on the carb for any crap that might have made it's way through the system. If thing seem clear and clean, spring for a new pump. If not it time to look thing over closely.

The carter pump has a chamber were the fuel circulates to prevent the pump from running up against itself. So no, using this pump would be a simple remove and replace procedure, no need for any additional lines.

Good luck...

Art

One other question about the Carter pump. reading through the instructions online, it looks like the fuel lines are hook up just like a Holley. In from the tank and out to the carb/regulator. Hyperpasta, you said the pump is internally able to return fuel when not needed to eliminate the dead head scenario and so my question is it is able to do this without any additional fuel lines added to the system? I cannot find anything in the installation manual showing a return line so just replacing the pump would give me return line capability and I could leave all the current plumbing alone.

Would this be correct??

Thanks again.

[Pro-Tour69]

Thanks Art for explanation on the pump. I also forgot to mention that I did rebuild the carb this year as well. The last time the boat was out was when I was adjusting and tuning the carb and then she quit and then I quit. Waited the 30mins then started it back up and putz home.

The worst part will be taking the tanks out but I feel it is an absolute must just to check and make sure there is no crud in them and also replace the lines just because they are 15 years old. Luckily living in Michigan gives me plenty of time to plan and do the work ugh.....

[hyperpasta]

Hey Scott,

Save yourself some work....

On the tanks grab a small inspection mirror and a flashlight and have a look inside of the tanks rather than removing them. If you want to get all Hi Tech about inspecting the tanks inners, head down to Harbor freight/Home depot/Sears and purchase a borescope/digital inspection camera. Run the lighted lens down into the tank and check them out. An $80.00 new tool you can add to your tool box is much better than ripping the tanks out then only to find out it wasn't necessary in the first place.

The lines are a given, but remember, they are after the tanks. you might want to recheck those float bowls in your carb, just saying....

Art

[HydroHaulic]

great idea Art... i want on of those cams.... that cost is almost as much to weld the hole i cut to inspect inside the tanks i cut... found out my tanks were made in 92 that the video above shows