# Fuel System Primer



## epanzella (Apr 17, 2020)

Because of the ethanol in the fuel every fall when I winterize my boat I take the fuel system (manifold, injectors, heat exchanger, hi-pressure fuel pump) off my boat engines for draining and cleaning.  In the spring I reassemble the engines and also replace the spin on fuel filters in the boat. That's all relatively painless but the part I really hate is getting fresh fuel from the tank thru the filters and all the way to the fuel rails so the motors can start. In the past I opened the fuel line at the tank and hooked up an electric fuel pump to push the gas thru the system all the way to the injectors. This entails kneeling in the bilge while covered with gas trying to prime that pump. Being as I recently had two knee replacements I figgured I had better come up with a better arrangement.  I picked up a vacuum generator that works off an air compressor  and made a liquid separator canister in order to suck the gas out of the tank right to the engines while keeping the liquid gas of the vacuum generator. I included a piece of clear hose so I could see when the gas reached the canister.  I think this would also be a good brake bleeder. Haven't used it yet but the suction is really strong.


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## Alexander McGilton (Apr 18, 2020)

Sounds like a good solution for your convenience.
One concern I have is that you are using what appears to be CPVC pipe and fittings for your catch can that are only intended to hold water.  Fuel is a solvent that could attack the glue and plastic.  I would recommend all metal construction, and hoses intended for fuels. Threaded fitting should be NPTF, and the ptfe tape intended for fuels.  

CPVC is not recommended to be in contact with gasoline.


			https://www.nrc.gov/docs/ML1820/ML18207A604.pdf


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## Tozguy (Apr 18, 2020)

Another approach might be to pressurize the fuel tank with a small shop vac blowing into the filler pipe, maybe?


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## Nutfarmer (Apr 18, 2020)

Make sure and have the bilge  blower on when priming the engine. Gas vapers  are heavier than air and will settle in the bottom of the hill forming an explosive mixture.


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## epanzella (Apr 18, 2020)

Nutfarmer said:


> Make sure and have the bilge  blower on when priming the engine. Gas vapers  are heavier than air and will settle in the bottom of the hill forming an explosive mixture.


Twin Outboards. With this device I won't even be in the boat.


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## epanzella (Apr 18, 2020)

Tozguy said:


> Another approach might be to pressurize the fuel tank with a small shop vac blowing into the filler pipe, maybe?


TOZ
I tried pressurizing the tank before I went the electric fuel pump route. It's really easy as the tank vent is accessible. Before I even reached a pressure that would register on my gauge (<2psi) the tank started to balloon up. (NOT GOOD! welded aluminum) The tank is approx 4 ft square and even at 1 psi that's a lot of P's.


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## FOMOGO (Apr 18, 2020)

Could also use this ( https://www.amazon.com/dp/B002YKGZBW?tag=duckduckgo-ffab-20&linkCode=osi&th=1&psc=1) , I've used one for years for one man brake bleeding and component testing. Mike


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## epanzella (Apr 18, 2020)

Alexander McGilton said:


> Sounds like a good solution for your convenience.
> One concern I have is that you are using what appears to be CPVC pipe and fittings for your catch can that are only intended to hold water.  Fuel is a solvent that could attack the glue and plastic.  I would recommend all metal construction, and hoses intended for fuels. Threaded fitting should be NPTF, and the ptfe tape intended for fuels.
> CPVC is not recommended to be in contact with gasoline.
> 
> ...


I was aware that CPVC  and the associated adhesives are not rated for continuous gasoline contact. Being as I had all these components on hand and could build this without being exposed to the black plague I decided to press on. After soaking samples of the PVC tubing in gas for 30 minutes with no  effect whatsoever I felt that the adhesive would be the main weakness of my gizmo. I machined everything so the assembly would have no glue in contact with gas except where the brass fittings were glued into the 1/2 inch tubes. I grooved the fittings and the interior of the tubes on the lathe and used epoxy resin to attach them. Epoxy doesn't really stick too well to PVC but with the grooves on the mating parts it acts more like a key than an adhesive. Thanks for the hedzup!


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## RJSakowski (Apr 18, 2020)

Installing a primer bulb like those used on smaller outboards will do it for you.  a few squeezes of the bulb and the fuel will reach the engines.




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						Amazon.com : primer bulb marine
					





					www.amazon.com


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## epanzella (Apr 18, 2020)

RJSakowski said:


> Installing a primer bulb like those used on smaller outboards will do it for you.  a few squeezes of the bulb and the fuel will reach the engines.
> 
> 
> 
> ...


I have fuel bulbs. To fill the lines, canister filter, fuel rail and fuel cooler for one engine takes over an hour. Then to do the other engine I need a week to recover the usage of my hand from 10,000 squeezes!


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## RJSakowski (Apr 18, 2020)

Then the pump in post #7 won't work either.

Your setup will be aspirating gas fumes into the exhaust creating a potential explosive condition.  At the very least, I would put a hose on the exhaust to direct it well out of the bilge.


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## epanzella (Apr 18, 2020)

RJSakowski said:


> Then the pump in post #7 won't work either.
> 
> Your setup will be aspirating gas fumes into the exhaust creating a potential explosive condition.  At the very least, I would put a hose on the exhaust to direct it well out of the bilge.


Read post # 5


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## RJSakowski (Apr 18, 2020)

epanzella said:


> Read post # 5


Then your gizmo is outside the bilge?  I guess that I assumed from post #1 that you were working in the bilge.


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## epanzella (Apr 18, 2020)

RJSakowski said:


> Then your gizmo is outside the bilge?  I guess that I assumed from post #1 that you were working in the bilge.


This device works on suction. It's replacing a stand alone electric pump that required me to  get down in the bilge to pump the fuel thru to the injectors. With this device I just hold it in my hand while standing on the ground behind my outboards. I hook it up to the fuel line right at the injectors and suck the fuel all the way thru from the tank. The cannister is just there to prevent raw gas from getting into the vacuum generator.


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## epanzella (May 16, 2020)

Just a followup. Using the device featured in this thread I pulled the fuel thru the new spin on filters and primed both engines in 15 minutes. It was done standing up behind the boat. This used to be a 2 hour project on my knees in  the bilge.  This is the best epidemic I've ever been on!


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