Help, my buggy has issues!

[pigpen]

I will describe this the best I can, it may get a little long winded, but I will keep it as brief as possible.

1. Car, Lightning Pro
2. Motor, Ofna 8 port race
3. Pipe, Ofna 063

4. Problem, will not hold consistent tune through out the tank.
I know that this is usually attributed through air leaks and or carb. I cannot get ahold of an OS20E as every where I have looked is out of stock and backordered from the factory. My engine is running around the 240-250 range. right up until it dies with a little over a 1/4 tank left.

5. Other possibilities, I notice that there are bubbles coming up through the fuel line to the carb. The fuel tubing is new and no cracks. The tank does not seam to have a crack either, as in I will put fuel in it and leave it overnight and none leaks out. I am thinking that I am not getting enough air pressure, or too much from the pipe, or the pickup in the tank is letting air in or something. Maybe the lines are too long, or too short?

6. Can any of you nitro gods help me on this? Please, and thank you. :write:

 

[flash183]

Originally posted by pigpen
5. Other possibilities, I notice that there are bubbles coming up through the fuel line to the carb. :

I wonder if your fuel pick up is too high or has a hole. It seems possible since you're getting bubbles and it dies at 1/4 tank. And that may also cause you to run a bit lean and raise the temp. I'd start with the fuel tank and make sure there are no leaks.

 

[mcvickj]

Submerse your fuel tank under some water then blow into one of the fuel lines. If you see any bubbles then you know you have a leak in your tank.

 

[gauner]

That would work except you need to make sure you don’t leave any water in it when fill it up.

Also without submerging the tank on water. Just blow on both holes and one hole at a time and see if there are any leaks.

Maybe one of the connections for the tubes came off of the tank. Or it became lose.

Hope this helps.

 

[zoeybadm]

replace the fuel tank and start eliminatig leaks one by one..new hose and so on..

 

[pigpen]

Yeah, I think it is the tank as well, there is a drastic change in tuning from full to 1/4 tank.

Could it also be one of the tubes too long or too short?

 

[militarymaxx]

Aside form the usuall air leaks (around the carb, fuel lines, tank), I had a similiar experience where the buggy would run fine and as things warmed up is would lean itself out and run warm and eventually flame out. What I discovered was I had overtightened the banjo fitting and when the engine warmed up enough an air leak developed around the two aluminum washers (one on each side of the banjo fitting). When it comes to air leaks, there are so many places to look at. Like some of the guys have already said, when in doubt replace it.

 

[pigpen]

militarymaxx, I hate to sound like a rookie, but I have to this time, what is the "banjo fitting" you are referring to? Dang, I sounded like a rookie. :stupid:

 

[jon2]

its the inlet "nipple" where the fuel line from the tank goes

 

[dgrobe2112]

get rid of that 8 port race.. cuz those ofna motors are the hardest motors to tune.. trust me.. i thought the same thing... then i got a OS motor and no more problems..

 

[pigpen]

Jon, do you mean the inlet nipple on the carb? I thought that too.

Dgrobe, I know I should get another motor, but I can't afford a whole new engine right now and I have a race Sunday.

 

[Hypedonrc]

You can ckeck for carb air leak w/ carb cleaner from any parts store. If there is a leak the rpm will, I think, go up when sprayed around carb (maybe down).

If your pressure line is too short it doesn't allow the pulses from your exhaust to even out, and can foam up your fuel witch will lean out the air-fuel mixture. use 7-9 inches of line.

 

[pigpen]

I have atleast that much on there already

 

[Hypedonrc]

Too much will not produce enough fuel pressure at the and of the tank.

 

[ImBroken]

Here's what I would do...

• Replace fuel tank with new
• Remove or replace external fuel filter if you are using one
• Keep trying to find the OS20E carb (Try RCBoyz.com) Email them & ask. It is not listed on their site.
  I have a Brand new Hyper 8 port stock carb, pulled from my mill if you would like to try it & see if it makes any difference.
• Remove, and blow through your exhaust pipe to see if theres any buildup restricting airflow.

Hope that helps ya out...

 

[pigpen]

Yeah, I will keep trying, thanks to all for all your help.

 

[pigpen]

any other inputs are more than welcome though

 

[pigpen]

I eliminated the tank leaking as a possibility for the problems. I have not eliminated the fule pick up as a problem, but the tank passed the submersion in water and blow test. Yes, I plugged the nipple to keep water out.

 

[pigpen]

I ran 3 tanks through it at lunch, what a difference. It is running alot better right now. Here is what I did. I know you should only make 1 change at a time so you know what you did to fix it, but I threw 3 things at it since I have limited time to test it.

1a. Tank leak test-----Passed <--- doesn't count as a fix since nothing was required.
1b. Changed and lengthened both fuel tubes
2. Resealed carb
3. Changed Fuel. I was running Blue Thunder 30%, Now I am using my Trinity Platinum blend 30%

I don't know which one worked, but it did, so for right now I am alot happier.

 

[pigpen]

I put Blue Thunder back in it, and the problems kinda returned, I wonder if I had some bad fuel. Anyways, the real test is tomorrow when I race again. I bought a fresh gallon of Trinity Platinum. Wish Me Luck!!!!!!:marshall: