I have a fuel problem.

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DarthRacer

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I'm going to try and describe this as well as I can.

My fuel tank has the primer removed.
If I remove the fuel line from the carb and blow into it while closing off the exhaust stinger, the system will hold pressure.
I made sure the carb is seated well.

Here is my problem.
I have trouble priming the engine after it is hot, mostly after one tank of fuel. I have the stock TRX and carb in right now and I have been watching the temps closely. It also has problems with air in the fuel line. It will stall and then I have a real problem priming it. I can get the fuel to the carb, but after I take my finger off of the stinger, the fuel shoots back from the carb up to one inch. I have to take my finger on and off the stinger while turning the engine over to try and get it primed. It is beginning to get frustrating and I stop having fun when this happens.

Does anyone have a clue to what this could be?
 

SkyMaxx

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This means your engine is running a little too hot or is overheated. When the fuel behaves in the manner you are describing, the cause is fuel boiling. When you push the fuel into the carb, it boils (due to excessive heat), the resulting "steam" if you will acts as backpressure on the fuel feed line, causing the fuel to get pushed back towards the tank.

The air you see in the fuel lines can be caused by either the above mentioned issue or by the normal tendancy for fuel to slosh around in your tank as you bash. Some air will get forced into the fuel line.

One question, what percent nitro is the fuel you are running? If it is 20%, then you should be good to go. Some solutions to your problem include:

The TRX Pro is a known hot running engine. You could either get a different engine.

Find a better heat sink to help lower the running temps.

Run a higher nitro percentage fuel to help lower the temps.

Run richer to help lower the temps.
 

Hunter

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Best guess your engine is running to hot. Whats happening is when your engine stalls and you try to restart it the fuel that gets in the engine is boiling off and causing back pressure that is pushing the fuel back to the tank. If you richen the mixx just a little the engine temps will go down and the problem should stop or at least not be as bad. Do you have a temp gun so you can tell us how hot your engine is running. And what kind of fuel are you running???

Looks like you got here first SkyMaxx.
 
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SkyMaxx

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So does that make me responsible for misinformation or you? or is it the guy who asked the question? Just kidding...

Good to see that my information and yours match. Means I'm not as dumb as Pirata would like to think I am...;)
 

Hunter

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Originally posted by SkyMaxx
So does that make me responsible for misinformation or you? or is it the guy who asked the question? Just kidding...

Good to see that my information and yours match. Means I'm not as dumb as Pirata would like to think I am...;)


If Pirata thinks your dumb that should tell you something, Iv found most of your info to be of good quality:cheerful: Well most of it:p
 

DarthRacer

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OK, I have a temp gun an my max temps are 315F.
I am using Cool Power 15% nitro with added castor oil.

When I richen this thing up, the performance is terible.
I was trying to find a balance between temp and performance.
Maybe I should go to 20%.
 

SkyMaxx

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315 is on the edge of too high. Even for a TRX Pro. The increased nitro content might help. As for decreased performance from richening the mixture, you don't have to go nuts on richening the mix to get good results. You need to bring the running temps down to between 250 and 280.
 

DarthRacer

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OK. Great info guys. I had a feeling it was temp related.
I'm going to get a used OS .15 from a friend that is getting out of R/C. Maybe that will work better for me. :)
 

SkyMaxx

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Originally posted by Hunter



If Pirata thinks your dumb that should tell you something, Iv found most of your info to be of good quality:cheerful: Well most of it:p

That was a bit of sarcasm...he likes to joke me for being an officer (ossifer as he calls me).
 

DarthRacer

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I'm getting the OS .15 today. :D

Hopefully I can get some testing in this week to let you guys know how right you were.
 

DarthRacer

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I am getting the OS .15 CV-X.
I buddy of mine has a new one of the exact engine, so now we can compare performance and settings.
 

nitro boy

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I have that same problem with my force 25 engine the problem started when my clutch was slippin would that make it run to hot i hav put new clutch an springs in but the problem is still there an my flywheel turning a pinky colour, it was running perfect until the clutch went an its driving me crazy any ideas guys?
 

Suicide

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uh oh here comes Rolex. i have no clue what make your flywheel turn pink
 

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I have that same problem with my force 25 engine the problem started when my clutch was slippin would that make it run to hot i hav put new clutch an springs in but the problem is still there an my flywheel turning a pinky colour, it was running perfect until the clutch went an its driving me crazy any ideas guys?

Look at all this dust, nitro boy! Get this mess cleaned up before Rolex shows up. Poor man is already fixated on keeping the place clean, you don't need him beating you with his cane!
 

nitro boy

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i have no idea wat u are talking about!
 
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