j winkelman

tHIS IS DRAG RACE RELATED .ON THE NITROUSE SIDE OF MY FUEL SYSTEM I USE A HOLLY BLUE AND WHEN I TURN THE PUMP ON IN THE LANE THE PRESSURE WOULD CREEP UP SO ,I DRILLED AND TAPED THE TOP SIDE OF THE REGULATOR AND PUT A RETURN LINE IN USING A NITROUSE FITTING TO RETURN THE FUEL ,I HAD TO TURN THE REGULATOR UP, BUT IT CURED MY PROBLEM AND THE PUMP DOESN'T DEADHEAD OR GET HOT ANY MORE.ANOTHER OPTION IS TO BUY A FITTING THAT SCREWS INTO THE INLET SIDE OF YOUYRE REGULATOR WITH A 1/8 PIPE THREAD TAPPED INTO THE SIDE (THERE TO PUT A FUEL PRESSURE GUAGE IN) OR YOU COULD TAP YOURE FITTING, IT USUALLY MAKES IT A LITTLE THIN THOUGH AND USE IT AS A RETURN IT DOESN'T RETURN AS MUCH AS ONE MADE TO DO THAT BUT IF YOU DO ONE PUMP FIRST AND TRY IT YOU WILL NOTICE A BIG DIFFERANCE IN THE SOUND AS IT DOESN'T DEAD HEAD ANYMORE.I WOULD NOT USE A BIG LINE OR I WOULD PUT IN A VALVE TO BE ABLE TO TURN THE RETURN FLOW DOWN INCASE THE PUMPS WONT KEEP UP ON TOP.

Cord

I'd go with the non marine pump. I have a marine and a non marine pump in my boat. The lower portion of the marine pump is black annodized and has a hole drilled in it to drain fuel. That's the only difference. If the o-ring should fail, this pump will leak fuel into the engine compartment either way. Trust me, nobody will ever notice the missing hole, it's pretty well concealed. When I added the return regulator I could actually hear the difference in how the pump labored, so that return regulator is a requirement.

TomR

I have been running the Mallory 140 Marine "system" for 21/2 seasons with no problems.
Did I not read the instructions correctly? I don't remember reading about the return line in the instructions.
I know that with a high pressure fuel injected system, you have to have a return, but you are running a much higher pressure.
I have mine set at about 7.5lbs at idle but once you are running it is always a little lower, and WOT it is around to 6. I could see the benefit at slower speeds, maybe I'll look at how easy it would be to add a bypass.

Cord

"Technically" a return line is not required. We are using them so the pump doesn't labor as hard when dead headed. I know that the pump has a internal bypass but it still seems to labor. I added the return line you could hear the pump was laboring much less.

p4-33

TomP,

The 4140M package comes with a 4207 non-bypass regulator, so that's why you didn't find a provision for a return line. This is my main problem, the only way to get the marine 140 pump is to buy the kit that you bought, and buy the bypass reg separately. This = spare parts. Bybass needs to return to the fuel tank with the same size line that feeds the pump.

Cord,

Thanks, but one more question: My Holley Blue setup (see below) has a yellow hose that runs back up to a port in the flame arrestor, and I was assuming this is some sort of vent that needs to return to the carb for USCG spec. Is this the "hole" you're talking about? Or is this the "guage port" that Mallory talks about? If it's the guage port, why does it need to vent back into the carb?

HP350, Thanks. I will call you and see if we can work something out.

Thanks,
Brian

p4-33

This is the return fitting that will run inline with my fuel fill line.

One IMPORTANT question about cutting into my fuel fill line: do these hoses have steel reinforcement in them? Sparks would be a BAD thing.

I still haven't figured how to keep debris out of my tank during this operation, and I don't know if removing the fuel fill lines prior to cutting will be an option. I just got new tanks installed, and there's foam and glue everywhere around the tank inlet. I'll look into removing them some more.

Thanks,
Brian

merlin540

if you want it to be bulletproof run a aeromotive A1000 with a fuel return regulator. remember when racing to finish first you must first finish. both of my race/pleasure boats have ran them for years so if it aint broke dont fix it

p4-33

Charlie, good to hear from you. I have looked at Aeromotive, and that's still an option. They are a bit more pricey, but after I end up with spare parts, these might be do-able.

I realized that my last post about sparks was a little on the idiotic side, so I dug deeper...

Before:

p4-33

After, problem solved.

merlin540

its not that pricey if it saves you from smoking a engine. who looks at the guages when racing. i dont. just hammer it