Fuel

[Thunderbutt]

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I'm still have problems getting this barge up on plan. New question on fuel. I have two tanks going to a transfer switch with 3/8 hoses, then 3/8 hose to the filter then the pump, then looks like a 1/4" tubing then # 8 to the carb. What is this small tubing shit, is that big enough to supply the 850 carb. It is stock on the HP500 motor. (Anybody with a carberated HP 500?)

[nitrofuel]

Our boat is set up the same way except you need to change from the fuel pump to the carb with 3/8 and no. 6 fitting. 501 BB ford with 850cfm Holley. I dont think this is your problem. I would check the distributer timing.

[SmokinLowriderSS]

I'm only runnig a 700CFM Holley, and am running 3/8 lines, all the way from tank to carb. Go bigger. Now, what's the problem getting on plane? Yes, check out the timing. Any shortage there will drastically cut your power down.

[Morg]

Definatly need bigger than the 1/4".
You could tell for sure with a pressure guage.
BTW- I run #10 from the single tank to the mechanical pump. with 1/2" fittings, #8 to the carbs, 1/2" fittings @ the bypass regulater, #8 back to the tank.

[nitrofuel]

Ran the boat today. Was running 73 mph fell on its face. Out of fuel. Raising fuel pressure for quick fix. Let you know tomorrow what happens.

[hondajoey]

Boats need fuel volume 3/8" line all the way from the tanks to the carb, and only about 6-7lbs of pressure, also check the lines that go inside the tanks, make sure they are not broken off or too small, my last boat had some home made pickup tubes that were way to small and didnt even reach the bottom of the tanks.

[Thunderbutt]

Definatly need bigger than the 1/4".
You could tell for sure with a pressure guage.
BTW- I run #10 from the single tank to the mechanical pump. with 1/2" fittings, #8 to the carbs, 1/2" fittings @ the bypass regulater, #8 back to the tank.
Pressure guage would only tell me the pressure. I think I need more volume.

[Morg]

Pressure guage would only tell me the pressure. I think I need more volume.
True, but a guage @ the carbs will tell you when you are losing volume. It takes volume to create pressure. If your fuel system is not transfering enough fuel to keep pressure @ the needle valve on the bowl, the presure will drop. You should always have at least 3-4 lbs @ the seat, That is a minimum. I run my deal on a low pressure high volume theory- 5-6 lbs @ idle, no less than 4lbs at WFO. Large capacity needle's in the bowls that don't have to fight to close. I believe this alows the bowl levels to stay more constant. BTW- I also believe a bypass fuel system is a must. Especially with low pressure/high volume deals.
A guage will tell you quickly if your problem is even fuel.
I had been fighting a stumble in my carb, thought for sure it was squirter size & squirter timing. Fought it for a few hours. Then we thought about disconecting my MSD timing box & running the motor with locked timing. Bing. Stumble gone. I would suggest starting with the simple things.
Good luck

[Thunderbutt]

Showing the linehttp://www2.***boat.com/image_center/data/520/586Fuel_1-thumb.JPG

[Thunderbutt]

http://http://www2.***boat.com/image_center/data/520/586Fuel_1.JPG
Bigger picture

[nitrofuel]

Boat still fell on its face. Dad and i are going to run 1/2 lines to the carb.

[Oldsquirt]

Thunderbutt, I cropped this from your full-size pic. From the looks of the bend at the top, that line is about crimped shut. It may not completely fix you performance problem, but it definitely needs to be repaired. That looks to be a serious restriction.
http://www.hotboatpics.com/pics/data/500/3633TBLine.JPG

[Morg]

TB,
I would say you are right, that line looks pretty restrictive.
Uh.. huh... huh... Hey Beavis I like made a fuel line.
Uh.. huh... huh... I uh like playing with my pipe, hu.. hu.hu.hu... I said pipe.

[Thunderbutt]

Thanks squirt. I will put on a new line.