stillcrazy26

I have a 5.0 MPI system on an engine that was taken down for repairs and the fuel system completely drained and disconnected. Now the engine is ready to be fired up and I am wondering if I have to purge the air out or will that little pump do it. I don't want to damage the pump. I have heard problems with people loosing prime on these systems and I am starting from scratch. My intent is to insert a primer bulb ahead of the fuel filter and prime the system. (I'll fill the filter first).What are the accepted steps to put the system back into service ?

stevesxm

none of the pumps like to be run dry and certainly getting the system primed is a good idea from that standpoint. the actualy fuel system will self purge so the " air issue is a non issue once the pumps move fuel etc... my boat had been out of service for some time when i bought it and neither of the fuel pumps would run when i first tried to run them. i discovered the had " rusted " up ... and i had to clean them and get them to turn at all before they woulkd start to work. then i ran loop of fuel with some marvel mystery oil in thru them for a while and they cleaned right up. if your have been sitting for any length of time, you might have a similar issue.

stillcrazy26

Thanks Steve for your actual experience . I am hopeing that once I get the filter full, which is higher and maybe get the gas supply hose to the pump full , it will be enough to wet the pump and start the action. I doubt that the pumps have much lift dry.

stevesxm

they do not. they are a vane pump and make little or no lift at all. on my boat i built two 2 quart accumulators... they were higher than the pumps. i fed those using low pressure hi volume lift pumps with tank returns so they were always full and gravity fed . the original power was carbs so the efi was new to the boat and i worried about the lift as you are.

tunertech

fill the filter as mentioned.
cycle the key a couple times.
Pop the Schrader valve on the fuel rail
repeat until you get fuel

start

proboat-wes

as per mercury,hook up a remote fuel tank,or hook to the existing tank with a primer bulb from an outboard and pressurerise the fuel system to lube the electric pump then fire up system

stevesxm

cycle the key a couple times.
Pop the Schrader valve on the fuel rail
repeat until you get fuel
start
find fire extinguisher
put out fire
call insurance company,
get claim denied
write a big check

stillcrazy26

Well we are having fun with this one.
I'm an old Carb guy from the '80s and have resisted getting into the new digital age for boats. I know the advantages but I had a bag of tricks that would always get me home with the old stuff. So thanks all you young wipper snappers for the suggestions.
I have heard a lot of complaints in the South about getting vapor lock with these engines. I know they added a check valve to the water supply to reduce drain back thru the pump but the problem is still there. Others carry a primer bulb. A separate container in line sounds good but creates another hazard. The factory routing of the fuel line up to the filter and then going down under the engine should keep some gas above the pump.

Trash

I did a complete rebuild on my EFI motor and when it was back together for the first run I had it on a stand in the garage. Fuel line from portable tank to mechanical pump. Turned motor over for a few seconds (roughly to 10 second bursts). Cycled the ignition so I could hear the electric pump run for it's allotted 2 seconds, then started the motor. No purging or other funny business. Started right up.

tunertech

lmao sounds like true experience speaking