hobdog

iTrader: (19)

I have run into a issue on my mbx5t. I am not running any fuel filters at the moment (not sure if there is one in the tank on these truggys). I just switch the fuel line to make it longer (put two loops of fuel line) and I am getting alot of air bubbles in the fuel line. When I go to start it, it will run and then sometimes shut off because of the air bubbles. At times it will shut off out of no where on the track, and when I look at it there will be air bubbles in the line. I have checked that tank for air leaks, and the lines and all seems good. I got to get this figured out, I have a race this weekend and the truck is running great besides the flame outs.

RC Dad

iTrader: (26)

If the fuel line is more than a year old, replace it. If it's fresh, nip off one inch from each end of your fuel line and try again. The stretching that occurs when you pull the line on and off the nipple is frequently the culprit when you get air bubbles as it weakens the tubing near the end. Try to help it off the nipple by pushing gently with a screwdriver while pulling.

AssocRacer

iTrader: (10)

Fuel line is cheap, i'd say get more...but you don't need a whole lot of fuel line. Long fuel lines can be very hard to get rid of air bubbles once they are there. I would make the fuel lines shorter. Longer fuel lines usually doesn't equal longer run times. Also, i'm not so sure i'd be running without at least one fuel filter. Most of the guys i run with (including myself) run 2 filters. That's where you're gonna get your extra run time.

hobdog

iTrader: (19)

well I will try everyones suggestions tommorow. I shorten up the fuel line and trimmed the ends. As far as the fuel filter goes, I have heard that they are prone to causing air bubbles. I definitely need one if my gas tank does not have one in it. Does anyone know if the mbx5t tank has a built in filter?

TRArena

make sure the screws fixing your tank are not too tight. If the tank can not 'wobble' freely on its mounts it can cause bubbles in the fuel line.

razzor

No matter what you do you will get air bubbles in your fuel line especially when running.
Your fuel gets airated from the sloshing in the tank.
Always good to have your fuel line about 8/9 inches long and/or have a inline filter or reservoir.
Double check fuel line for any leaks or split ends and then look at maybe picking up idle or check bottom end tune.

pitpop

there shouldn't be air in the fuel line... these kinds of problems can drive you nuts, but it sounds to me like a tank issue

normally this is caused by the tank.. if your fuel line is good, it's the only other thing it could be

we run a filter, and it doesn't cause any problems... sometimes it traps air after sitting in your pit, but with a few minutes of running, all the air gets pushed out

I tip the car back to get the air out during warm up.

IanWright

iTrader: (1)

Take out your tank and use fresh fuel line, dunk the tank in a bucket of water, pinch one end of the fuel line and blow into the other length. If you see bubbles you have a crack in the tank. If not and a change of fuel line doesn't do it... ummmm... erm... i am out of ideas!

David Day

iTrader: (4)

+1

pitpop

sorry guys, but that won't tell him anything

if the pick up is sucking air, it can do it inside the tank, and there will be bubbles in the fuel line, even if the tank it air tight

just bite the bullet, and get a new tank, sometimes they are bad

asw7576

There is always bubble situation within fuel lines. You can minimize the bubbles occurance with inline fuel filter within the fuel line.

Don't worry so much about fuel bubbles as long as your engine is running perfectly.

DOMIT

iTrader: (1)

I was fighting this problem last week... replaced the tank, no dice... replaced line, shortened line, nothing helped. It would go normal lean normal fat lean tune was all over the place, couldn't get it to behave.

Then I pulled my carb off and re-sealed it with silicone. Problem solved.

I have no idea WHY, but it was a suggestion from my bud and it worked.

wingracer

iTrader: (24)

A loose or leaking banjo fitting (the nipple on the carb under the HSN) can cause all kinds of bubbles.

pitpop

coming from the tank?

Twitchy Kanai

iTrader: (9)

Air bubble(s) will not flow in opposite direction of fuel flow.

I also have air bubbles that I can't get rid of. Bubbles are not big they are very tiny but it still bothers me enough that I've tried several new tanks and several feet of new lines and the bubbles are still there.