Figure 8 fuel pump concerns

[strauss18]

Hey yall, having some WOT fuel delivery concerns with my 86' mariner magnum 150, long story short pump can't seem to keep with with fuel demand at WOT. will run fine under 4k rpm but over that it sucks the bowls dry and leans out in stages if i don't back off and calm down.. i have replaced diaphragm kit and "tested" the check valves, replaced all fuel lines between tank and engine, omitted fuel filter for diagnostic purposes. I can't seem to find any real information on how to diagnose the check valve operation. wondering if the inlet side isn't keeping up under high demand and back flowing?
also been looking for advice on an electric pump alternative. have read some bits about a holley in line pump but will they not overcome needle strength at 7 psi? closest i can find is the 1.5 psi-4 psi pump seems about right. Any input on that ?

[rock]

Low pressure electric is a viable solution.

Rock

[strauss18]

Low pressure electric is a viable solution.

Rock

Should be in that pressure range eh? not sure how sensitive these carbs would be to higher pressure

[derekfl]

https://www.amazon.com/dp/B00L8IHM9K?psc=1&ref=ppx_yo2ov_dt_b_product_details

[skialot2]

Check your anti siphon valve at the gas tank connection. They go bad and restrict the fuel flow exactly like you are describing. I take them out I have had so many problems.

[pcrussell50]

https://www.amazon.com/dp/B00L8IHM9K?psc=1&ref=ppx_yo2ov_dt_b_product_details

Do those need to be on a pressure switch or do you just flip it on before engine start and leave on until shut down?

I have one of those that I use to suck fuel out of tanks at the end of the season

-Peter

[tlwjkw]

use a relay to power tha pump.. power tha relay with any purple from anywhere on tha boat/motor.. will turn on pump when ya turn on tha key...

[strauss18]

Well, had the boat out. same problem runs great sub 4k rpm anything over that power is good for about 15 seconds and bleeds out, let it idle for 5 seconds and will pick up shortly again.
new electric pump 3-6 psi at 30 gph allegedly. still seems like a fuel delivery problem but im at wits end with this thing. i can't seem to find a rpm cutoff for the stator between low speed and highspeed windings.
may need a not pos chinese fuel pump?

[tlwjkw]

Did ya eliminate tha bulb and by pass/remove tha mech. pump after ya installed tha 'lectric pump?.. both needs ta be done after ya add tha 'lectric parts...............

also ya didn't mention anythig done and/or checked with tha carbs.. needles n seats, float heights?

seems like i remember tha stator goin' from low ta high around 25/2800?. i know it was 3 grand or less..

[strauss18]

I ran completely new line for electric pump, carbs have been gone through and reset. i located the issue late last night... the frickin quick connect ball must have some crap in it. took it back to the lake screaming 5500 ripems for 20 mins no problems. thanks for the help fellas!
now time to decide if i return to oem pulse pump or upgrade the cheap chinese pump to a proper electric pump setup. hmm.

[tlwjkw]

good on ya... didn't mention that.. jus didn't think!.. don't know anyone that still has that thing in their fuel system..... especially when tha 'lectric pump is added

look on summit for a good pump and relay............"mighty mite" pump and Summit Racing™ Fuel Pump Relays SUM-890023

keep tha cheapy in a baggie on tha boat....

[strauss18]

good on ya... didn't mention that.. jus didn't think!.. don't know anyone that still has that thing in their fuel system..... especially when tha 'lectric pump is added

look on summit for a good pump and relay............"mighty mite" pump and Summit Racing™ Fuel Pump Relays SUM-890023

keep tha cheapy in a baggie on tha boat....

roger that, motor deffinently starts easier with a electric pump. Probably will go that route and dump the pulse pump on eBay.
those mighty mite pumps okay at that pressure range ? I thought should be no more then 7 psi?

[tlwjkw]

maybe memory isn't what it use ta be! thought that pump was 7lbs?..

guess there's more than one "mighty mite".....................

Holley 12-427 32 GPH Mighty Mite Electric Fuel Pump, 4-7 PSI

others that are decent....

Carter Universal Electric Fuel Pump Automotive Replacement 12V (P4070)

Holley (12427) Fuel Pump

[skialot2]

I ran completely new line for electric pump, carbs have been gone through and reset. i located the issue late last night... the frickin quick connect ball must have some crap in it. took it back to the lake screaming 5500 ripems for 20 mins no problems. thanks for the help fellas!
now time to decide if i return to oem pulse pump or upgrade the cheap chinese pump to a proper electric pump setup. hmm.


Hi, I have this old electric pump that was used on my 2.4 Bridgeport Carb. If I remember correctly it pumps at 5 psi, self regulated. connect and go. If you want it just pay for shipping.

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