fuel pressure check valve

[izitbrokeyet?]

Does anyone here use a check valve on the pressure line? I have a couple of very small check valves that I’ve thought about installing between the pipe and the fuel cell. I’m thinking it could help me to keep my motor alive in a wash-down, spin-out or similar course type situation. Given that the fuel cell pressure will decrease during a wash-down causing a lean condition since the cell pressure will evacuate through the pipe pressure tap , killing the motor from the lean.

Has anyone used such a check valve with success?

 

[Watercadet]

I run a check valve on my road cars incase of inversion and such. No adverse affects. Pressure stays up and no fuel in the pipe!

Adam

 

[Jerry Wyss]

Yes I've used one in three different boats. A highly modified K&B 7.5 OB on a mod 35in Bandit KILLER. The boat cowl has a

narrow waist toward the back which forces you to use two tanks in a "stair step" config. Before the check valve , the boat never

lived up to its mods,,,just out of the" Blue", I just decieded to change the Geraghty carb to the stock one and add the check

valve,,,Gawd! it took off like a rocket! and would run the tanks to the to the last drop, Next day I put the Garaghty carb back

on and it did'nt run as strong and motor was erratic,,it did'nt like it at all.

I've used one in a Phil Thomas SS45 with the Picco 45 Blackhead Drumrotor; with again the "Spraybar" type stock carb,,Runs

really strong, like these motors usually do.

Also used one my Thunder Tiger OB on a 28 1/2inch XTR,,The "tigers" are well massaged and run well,, but they did'nt like

the check valves either. Apparentlly, the spraybar carbs are the key and especially with a low tank situation. I've talked about

this before on this site . accually it was my first topic. One person replyed and said" you won't get any more pressure" He did'nt

"believe there would be any pressure loss between piston pulses at 27,000 RPM". Thats Fine if all things are equal,,but the

engine is Never at a constant speed or load and there will be some loss. The check valve will hold all it gets and deliver it

only to the engine,,,so there is a greater amount of pressure available. No?

 

[MarkScott]

My K&B 3.5 OB was flooding all the time after switching to a grim tank. Motor is using an exhaust throttle and crank pressure, not pipe. When using a 6oz w/ 2oz hopper, motor ran fine. After installing a Kustom Kraftsmanship ball check valve, the problem went away. Wish I could fine more of these little units.

Mark.

 

[DaddySundown]

Mark,

Tower has check valves. There are 2 of them, one is for gas and the other for nitro.

Foremost check valves

 

[Jerry Wyss]

I've used a couple different makes, but one made by Y.S. engines,( a maker of Model Airplane, Helicopter and

Pressure Pump Type 4 cycle engines) is the only one I can remember,,7 or 8 dollars. Oh yeah," Perry" is the

other one I have. One of the problems I've had using these things is that, they have to be disconected to

fuel the boat,,,and I have forgotten, Way, Way, too many times to hook it back up. I think Ron Olsen brought

this point out last time I talked about this,,and Boy was He right.

 

[Jerry Wyss]

Another thing, I heard it's not a good idea to use the plastic body type you see in Tower Hobbies as I don't

think they were designed for exhaust gases,,you don't want the thing to foul when your tryin to find the needle,

it could possibly go very lean all of a sudden as the needle setting will be many "clicks" in from where you

would normally run.

 

[Scott Schneider]

In my days of running outboards i made a check valve for the fuel delivery line, Not pipe pressure.

My intent was to keep the fuel head above the fuel level in tank. Very easy to start once primed, and engine would come on and off the throttle much better.

If engine sputtered or backfired it would not loose the fuel at spray bar, Check valve kept fuel all going one way towards engine.

Scott

 

[boaterbill]

I definately don't like them, because if the boat happens to die out there, ( for whatever reason) the pressure that's locked in the tank will keep pumping fuel untill the preassure is equalized.

Waste a lot of fuel not to mentionl fuel running around the inside of the hull. <_<

Bill

 

[Propjockey]

Bill has a point...but I haven't found it to be a problem. I used check valves in the pressure line on my airplanes and found that they ran much more consistantly. When I switched to boats, I just kept using them...although the effects aren't as noticable.

 

[MarkScott]

DS, Thanks for the link. Not exactly what I'm using.. The unit I have is inserted into the fuel line, not an exterior unit as the Foremost units. I'll have to take pics when I get home from work today..

Mark..