scale won't keep running

[u60]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.

Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

 

[u60]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.
Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

One more thing- I have the same exact set up in another hull and it run;s like crazy!!! The only difference is the fuel tank shapes. The tanks are taller from top to bottom. The hull is different as well. It weighs about 2 lbs less. Everything else is identical.

 

[Russell Bear]

First thing I can see is that the pipe is a little short for that heavy of a boat I believe....

 

[drwayne]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.
Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

what size is pressure line and fitting on pipe ?

I use a 5/32 hole on the pipe tap.. same for all tubes.

W

 

[SayMikey]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.
Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

what size is pressure line and fitting on pipe ?

I use a 5/32 hole on the pipe tap.. same for all tubes.

W

Whats the low and high needle settings? the main may be a little lean

 

[harvknox]

If this is a boat that has a little mileage on it,check for trash in the fuel system.I went thru the same problem a few weeks ago.Turned out to be a bit of carbon sludge in the Bob Violet needle.The pressure fitting on the pipe was partially clogged.We flowed the needle and carb ,but saw nothing.I had a thread under general boating a few weeks ago and got good suggestions.

Harvey Liberman

 

[Don Ferrette]

"Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out."

The pipe is too short, especially for a tweaked 255 prop in an 18 pound boat. Pull the pipe out to 12" and start from there. Close the 9B throttle fully and turn the low end needle in until it bottoms then back it out 2 1/2 turns. Run the boat and get your high end mixture set a touch on the rich side then start shortening the pipe until it just starts to sag in the corners then bring it back out 1/8". From what I have seen so far the billet pipes like to run a touch longer anyways. B)

 

[Greg Hahn]

"Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out."The pipe is too short, especially for a tweaked 255 prop in an 18 pound boat. Pull the pipe out to 12" and start from there. Close the 9B throttle fully and turn the low end needle in until it bottoms then back it out 2 1/2 turns. Run the boat and get your high end mixture set a touch on the rich side then start shortening the pipe until it just starts to sag in the corners then bring it back out 1/8". From what I have seen so far the billet pipes like to run a touch longer anyways. B)

Don is right on here, also keep an eye on water in the hull. The greenie and 9B is a great combo but it will pull water that's splashing around in the bottom. I've had to use a shroud on the carb to keep the water out. Pipe should run between 11 5/8" and 12"

gh

 

[Wesleys Custom RC]

Man I fought one last year for 2 weeks and tried everything before I found a crack in the 2 year old water pick up!! Kept thinking it was a leak in the pressure or tank but could not detect anything till I finally took the tank apart. I have also had trouble with the CMB remote needles. Nitro is very corrosive on them.

 

[Mike Cathey]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.
Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

Sounds like the fuel pick up line inside the main tank is either cracked or broken off. If you are using brass tubing (vs. stainless) you can save yourself a lot of greif by replacing the tubing and the stoppers every year. 5/32" tubing is the minimum for a 67.

 

[bsmtboy2]

Don is right on about the pipe and take it from someone who has dealt with the fuel draw issue...change the tank brass,stoppers, and lines every season.

 

[u60]

Hello- Looking for some ideas... Here's my set up. CMB Greenhead- OS9B Carb, Andy Brown Billet Pipe (set at 11" from center of cylinder to weld) Boat weighs about 18lbs running an Andy Brown S255 (tweaked a bit, thinned and cut down sightly) Two tanks- pressurized fuel system. 5/32 tubes in tanks, large fuel line through out.
Here's the problem- Boat will not keep running more than about a lap... It seems like the boat is running out of fuel. It seems like it goes very lean then dies out. throttle response goes first, it won;t get up on pipe- then dies. Taking a look at the fuel line going to carb there is no fuel in the line after it dies but tanks still have plenty of fuel.

Any ideas? The tanks are under the decks and pretty thin (top to bottom) The pick ups are in the correct spot to stay wet, etc. I'm thinking I will strap a different tank in the engine well and try that... I think it has something to do with fuel system.

Any help would be appreciated.

Thanks-

Fred

what size is pressure line and fitting on pipe ?

I use a 5/32 hole on the pipe tap.. same for all tubes.

W

It's all 5/32's through out the fuel system.

 

[u60]

Thanks for all the suggestions. The tanks do have all new tubes, etc. I have pressure checked the tanks, fittings, tubes, etc by filling them with a bit of air. Nothing leaked. So perhaps it's the pipe issue. I'll try adjusting the pipe length and re check the carb settings and give it a go. Thanks again for all of the help! I appreciate it.

Fred

 

[FloridaScaleBoater]

Pressure testing the tanks with air does nothing for you, if the lines INSIDE the tanks have a crack or hole

If it's a 2 tank system, fill both tanks the way they would be plumbed in the boat,. Draw the fuel out of the tank (with your pump) that would go the the carb or remote needle.

Make sure the fuel is drawing freely from the second tank to the first, if you end up with air in your first tank before the second tank is empty, you have a problem with the fuel transfer from tank two to one.

watch for air bubbles in the line coming from the first tank to the needle or carb (there should be no air bubbles) while drawing the fuel.

 

[u60]

Pressure testing the tanks with air does nothing for you, if the lines INSIDE the tanks have a crack or hole
If it's a 2 tank system, fill both tanks the way they would be plumbed in the boat,. Draw the fuel out of the tank (with your pump) that would go the the carb or remote needle.

Make sure the fuel is drawing freely from the second tank to the first, if you end up with air in your first tank before the second tank is empty, you have a problem with the fuel transfer from tank two to one.

watch for air bubbles in the line coming from the first tank to the needle or carb (there should be no air bubbles) while drawing the fuel.

Thanks for the suggestion. I flowed the fuel as you described and it seems fine. I have reset the carb settings and moved the pipe to 12 inches from center of cylinder to weld. I'll post again once I give it a shot.

Thanks Fred