Chasing a Gremlin

[FowlZurk]

Serial #OT131347 40ELPT 4s

This motor will run great first thing in the morning, but later in the day it will cut out or speed up then slow down at WOT. This started around July, i replaced fuel line from the tank, replace bulb, replace fuel filter, and lastly replace fuel pump. Next thing I’m trying is Power Tuning the Carbs.

Why does it run great first thing in the morning is puzzling me.

Thanks John

[EuropeanAM]

Are you pumping the primer bulb firm before EVERY SINGLE engine start (not just the FIRST start of the day)?

Built-In or Portable Fuel Tank?

[FowlZurk]

Built-in tank on a 16’ Range Cherokee aluminum. No, I’m not pumping bulb before each start. Should i be? Thanks for responding.

[JOE54]

check for fuel restriction between mtr and tank or in tank too, bulb may be culprit

[Gamblerman65]

Anti siphon valve if you have 1.

[JOE54]

+1 ^^^^^

[FowlZurk]

Thanks for all responses.

Very frustrating. New bulb, fuel filter, and fuel pump. As well as line from tank to fuel pump. Actually removed tank in July, cleaned anti-siphon on top of tank, cleaned tank it’s self, sending unit cleaned. One item I’m considering changing is the quick disconnect between the bulb and fuel filter, and running fuel line from bulb direct to fuel filter.

Don, i live in the dang desert so a lake that i can run WOT is 2 hours away, but i will try your suggestion of pumping bulb each time before running. This motor has run flawlessly for 10 years without having to pump bulb each time.

Thanks John

[EuropeanAM]

Don't overlook pumping the bulb. This is especially critical in warmer weather, and/or higher elevations.

Your engine's fuel pump is designed to pump liquid fuel (not vapors)- so it doesn't react well to fuel vaporizing in the supply line.

Pumping the bulb helps to make sure that LIQUID fuel is available to the pump (and fuel system).

[FowlZurk]

Thanks Don

[FowlZurk]

.

[FowlZurk]

Don, sent you a PM.