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redsnapper386

Regular Contributor
hi guys, i posted a few days ago about a mech fuel pump not pumping.i have since talked to the supplier,and they tell me the pump has to be primed on the 1st start.how do you prime a mech pump.i have never done this in the past.all new lines,all new every thing on this 350 alpha 1.the old pump only put out 2 lbs on the gauge test.i cant come up with a safe way to add fuel into the pump.thanks in advance.
 
do you have a fuel separating filter in line before the pump and if so did you replace it. If you did and did not fill it with fuel that could be your issue.

Some mech pumps cant over come the air volume in a separating filter..........

If you don't have one the remove the hard line from the pump to the carb, then hold the pump and hand pump it. Best if it is lower than the gas supply but if you don't want gas in the bildge then pull the pump out and hook it up to a separate fuel source such as a gas can with a fuel line in it and connect it to the pump. Just make sure the pump is lower than the gas level in the tank.
 
kghost said:
do you have a fuel separating filter in line before the pump and if so did you replace it. If you did and did not fill it with fuel that could be your issue.

Some mech pumps cant over come the air volume in a separating filter..........

If you don't have one the remove the hard line from the pump to the carb, then hold the pump and hand pump it. Best if it is lower than the gas supply but if you don't want gas in the bildge then pull the pump out and hook it up to a separate fuel source such as a gas can with a fuel line in it and connect it to the pump. Just make sure the pump is lower than the gas level in the tank.
Click to expand...
ghost,thanks for reply,yes i have a fuel water seperator,and it was primed on install,i have a new pump exchange on the way today.also,thi is a seiera pump,and i will be going back to quick silver.at least all the plumbing will be in stock locations.thanks again
 
The brand is not always important....what is is how long it was sitting on the shelf.........

Let us know what works.......
 
redsnapper386 said:
how do you prime a mech pump.i have never done this in the past.all new lines,all new every thing
Click to expand...

Do you own a Tempo Oil Boy extractor? If not, you would enjoy owning one, and for more reasons than for oil changing!
The Oil Boy is excellent for priming a fuel delivery system, purging a cooling system, sucking bilge water up, etc.

Connect the Oil Boy suction line to the fuel pump outlet line, give it a few gentle pumps.

It will pull fuel through the Anti-Siphon vavle, prime all lines and fuel filter canister, as well as priming the mechanical pump diaphram area.
The fuel pump's check valves won't even know what's happened!


.
 
RicardoMarine said:
Do you own a Tempo Oil Boy extractor? If not, you would enjoy owning one, and for more reasons than for oil changing!
The Oil Boy is excellent for priming a fuel delivery system, purging a cooling system, sucking bilge water up, etc.

Connect the Oil Boy suction line to the fuel pump outlet line, give it a few gentle pumps.

It will pull fuel through the Anti-Siphon vavle, prime all lines and fuel filter canister, as well as priming the mechanical pump diaphram area.
The fuel pump's check valves won't even know what's happened!


.
Click to expand...
thanks richardo,will get one thats the way to go.
 
If you don't want to spend the money on the extractor, plumb in an outboard style primer ball downstream from your water separating filter. This will prime the filter bowl and fuel pump.
 
bilge rat jim said:
I never suggested this as a permanent fixture- only a cheaper method of priming a stubborn fuel system. Once the pump is primed, you remove the primer ball.
Click to expand...

Didn't think you did, just want to clarify to the O/P . A year or so ago there was a post on one of these forums where they had done just that, installed a OB hose/bulb permanently.
 
bilge rat jim said:
If you don't want to spend the money on the extractor, plumb in an outboard style primer ball downstream from your water separating filter. This will prime the filter bowl and fuel pump.
Click to expand...

jim, I must admit...... I too thought that you were suggesting a permanent installation.
Please take no offense at our correction....... we're simply looking out for all, including those who may have misinterpreted your comment.

All is good! :D

.
 
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No offence taken- and you're right, I didn't make it clear that the ball should be removed- sorry!:( But, lets get back to the root cause of this pump not drawing fuel. I've only run into this a couple of times. Once was a bent push-rod, clearly a "mechanical failure". The other problem I've run into is a partially blocked sediment screen in the tank pick-up.
 
I ran into this once many years ago on my Chrysler 318 that did not have a water sep filter. The factory original mech pump's intake valve rusted.
 
Yes..... lets get back on topic! :D

In all of my years of experience with the SBC, I've yet to see a bent fuel pump push rod. I can't imagine a mechanical pump lever arm being stout enough to over-come a push rod and cause it to bend!

I do agree that a clogged pick up tube screen or bad anti-siphon valve may prevent or slow down an initial prime.
These are designed to pump liquid gasoline, but given enough time, they should pull a vacuum well enough to prime.


When changing a fuel filter alone (for example), I always start and operate the engine prior.
I then very carefully Pre-fill the new cartridge approx. 80% or so before installing it.


If still NO GO....... I'll suggest the Tempo Oil Boy again.


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