Last season I had issues of fuel starvation on both engines after my repower. I checked flow coming out of the pump and it was not getting it done consistently. Swapped the Jegs pump for another, same issue. Removed the line from the tank and put it in a 5 gallon portable tank and the pump then had plenty of flow. Thought it was the check ball at the top of the tank so I replaced it on one line with a new one and tested again. Same issue still. It seems like these little 4.5 psi pumps have plenty of volume me without the check ball in place but struggle to get it done with it. Thoughts or recommendations on how to fix the issue? Engines are 1998 Merc 5.7 with 2 barrel carbs.
No fuel coming from tank
- Thread starter Rick_D
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- Sep 16, 2003
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Make sure the fuel lines are the correct sizes for new engines especially if the new engines have more HP. Are you sure the pumps you are using are the correct ones for your engines? They may be able to pull fuel From a shallow portable tank but not from a deeper tank
Other wise, you may have restriction at the bottom of the tank pick up. There is usually a screen there. Try blowing air thru the pick up to
Clear it
Other wise, you may have restriction at the bottom of the tank pick up. There is usually a screen there. Try blowing air thru the pick up to
Clear it
It's not a check valve, it's an anti-siphon valve. Like a check valve, but intended to provide just enough restriction in the forward direction to prevent the siphoning of fuel into the bilge should a line break. If you bought a check valve, it may be providing too much restriction.
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Did your old motors have mechanical pumps, and new ones electric? The electric pumps, at least the Holley Red I’m using, states in the install manual that the pump should be installed near the tank. not near the motor. This may be a problem for the motor I’m getting ready to drop in my boat - wish i would have read this BEFORE I bought the pump!
from the instructions…
“The pump MUST be located below and as close to the tank as possible. This is necessary to allow for an adequate fuel supply. The pump is designed to push fuel and not designed to pull fuel out of the tank”.
www.holley.com
from the instructions…
“The pump MUST be located below and as close to the tank as possible. This is necessary to allow for an adequate fuel supply. The pump is designed to push fuel and not designed to pull fuel out of the tank”.
Holley 712-801-1 97 GPH RED® Electric Fuel Pump
The world famous Red®, Blue® and Black® fuel pumps are the most recognized performance pumps of all times. They have been powering racing legends and street enthusiasts alike since the early 70's. Their time proven rotor/vane design is known to get the job done in an affordable package. Designed...
www.holley.com
Last edited:
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It is also wise to remove the dip tube and check to see if there is a clogged filter on the end.
Lines are 3/8 and provide ample volume when hooked to a portable tank but fail to pull from the large tank. There are no clogs on the fuel tubes running down into the tank as they were checked last season. Also, last season I ran the boat with the fuel fill cap off thinking it was a clogged vent but that did not fix it either. The fuel issues are happening on both engines pulling from the same tank and only started after the repower with the new pumps. Previous pumps were mechanical and I NEVER had a problem with them. Wish I could have stayed with those. I see Jegs has a least two different pumps....1 is 2-4 psi and 50gph and the other is the 6-8 psi and 75 gallons per hour. I'll take a look and see if I can figure out the one that I have....maybe i've got the 50GPH and it doesn't have enough strength to steadily overcome the check ball? What pumps are others using