Auxiliary Fuel Pump?

[RJM]

My starboard engine 8V71N, likes to start fine all of the time, but my port engine (sama), when cold after a spell of sitting, takes some cranking. The captain thinks that it is just fuel-starved after sitting for a while and suggested that I consider putting in an electrical fuel pump in line. He said that he has seen this done before and says that it uses a hold-to-run switch that primes the engine. Or, as an alternative, starting fluid. Mostly seems to be a cold weather issue, I think. Thoughts?

 

[Pascal]

I m a big fan of having priming pumps on engines and generators. Useful when changing filters especially if you have to do it underway and want to be back in business quickly.

A Walbro pump is pretty cheap along with the few fittings required to have it in parallel

 

[Captain Ralph]

Or, as an alternative, starting fluid. Mostly seems to be a cold weather issue, I think. Thoughts?

Cold issue? Block warmer.
Fuel issue, check for leaks and/or add a priming pump.
Starting fluid is for emergencies only. Even then I do not recommend it.

 

[brettportzer]

If the engine is "fuel starved" after sitting, that probably indicates there is a leak allowing the fuel to return to the tank.

I had this issue for awhile, if I shut off my fuel valves after shutdown it was fine, otherwise my fuel would run back to the tank and my racors would be empty.

I finally found the leak, ironically in the fuel priming pump plumbing.

I no longer have to shut off the valves and the fuel stays in the filters and lines.

 

[RJM]

I m a big fan of having priming pumps on engines and generators. Useful when changing filters especially if you have to do it underway and want to be back in business quickly.

A Walbro pump is pretty cheap along with the few fittings required to have it in parallel

Looking into the Walbro pumps. What pressure should I be looking at? I assume that I will be stepping down from32V, so is 12V ok or should I do 24V? I see that they have dedicated marine CG approved pumps.

 

[Pascal]

Looking into the Walbro pumps. What pressure should I be looking at? I assume that I will be stepping down from32V, so is 12V ok or should I do 24V? I see that they have dedicated marine CG approved pumps.

Pressure isn’t important, you need volume not pressure.

I think the USCG approved pumps are certified for gas.

I would get 24v as you could feed it directly by tapping 3 of one your 4 batteries bank.

 

[doc g]

I ran a 24 volt prime pump on 32 volts for years . The length of time it runs it never was a problem.....Pat

 

[bigbill]

i'm thinking of doing this also, where do people tap into the fuel supply and where in the output to each engine? i was thinking a T in the line near the fuel supply by the selector valve?

 

[Pascal]

Best spot is two out Tee and valves right before the racor. This way you can use the pump to fill the racor.

 

[SKYCHENEY]

But Racor recommends that you not push fuel through them but pull. You need to mount it after the racor for priming, before to fill. OR make up some valves to bypass so you can do both.

 

[Pascal]

I ve run a number of boats with the priming pumps up stream from the racors. No issue. You don’t want to pressurize racors but a few psi’s isn’t going to cause any issues

 

[SKYCHENEY]

Do as you like but a pump before the Racor is not right. If you want a pump to fill and prime, buy the one that Racor makes specifically to fit onto the 1000.
Then you don't need to do any piping or valving. lt fits just above the bowl on the Racor. Just wire it and you're ready to go. I believe that kit also comes with the lid that has the vent plug on it. You crack that vent and turn on the pump to fill until you get fuel at that screw, then tighten.

 

[Bob Quinn]

If you search "Correct place to bleed the fuel rail?" I posted some pictures where I tied in when I was having an issue.

I didn't tie into the fuel system but tied into a pail of fuel, so where to pull fuel from is not shown.

Weather or not I picked the correct or best spot I don't know, but this worked for me.

My issue was a couple small leaks, one in the fuel pressure sensor connection and one back at the racors in a copper line fitting.

I did need to crack a fuel line fitting loose when running the priming pump as it was creating an air lock. What I should actually say is "I think I needed to crack the fitting loose" I never actually tried it without doing that. All I know is that with the fitting cracked loose and the primer pump on, it would take 10 to 20 seconds of air bubbling out before pure fuel would start to trickle out at the fuel pump where I cracked the fitting loose.

 

[MadHatter53]

I have also been considering a pump to make filter swaps easier and to compensate for a leak somewhere that I can’t find. My twin racor 1000 will drain below the inlet piping leaving about an inch or two of fuel in the bowls. There’s no leaks that I can find up to the fuel control valves or what I can see past them. Even with the valves off it drains out.

 

[stewart]

I have used Walbro pumps for priming on my 871's for 20 years

Cheers Stewart