nitro sport starting/running issue

[danarosetti]

Since I couldn't figure out what was wrong with my car myself, I have come here for some advice. I thought for sure I had it figured out, but not the case. So here it goes.

Over the weekend I was running my car with no problems, doing some fine tuning. The car was running like a top. Then I ran out of fuel. I was running 10% traxxas nitro fuel. Went to the LHS and bought some 20% traxxas nitro fuel. Came home and fueled up, couldn't get the engine to start. I noticed that when I covered the exhaust to prime three engine there was no fuel moving through the line to the engine. I knew that my stock exhaust had a crack in it so I upgraded to to the tuned aluminum exhaust. Still no movement of the fuel. I pulled the line off the exhaust and blew into it while trying to start and it fired up! Ran it around, but if I gave it more than half throttle it would die out. If I didn't get right to the car to restart it, I would have to blow into the tube again. So I tried setting the tuning back to stock and still no luck with the starting or the running. I even a new glow plug in... No luck.

Any ideas? I'm just about out of ideas of what it could be.
Thanks in advance folks.

 

[Phins Fan]

Just a thought but whenever you change fuel % you trypically will have to retune accordingly. The different nitro %'s run different from each other.

 

[SchrodeMode]

How old is the car, did it sit up for any length of time? Check your fuel lines, the coupler between the header and pipe, along with the seal on the fuel tank's cap, if those are all good look at the gasket between the engine and header.

 

[danarosetti]

How old is the car, did it sit up for any length of time? Check your fuel lines, the coupler between the header and pipe, along with the seal on the fuel tank's cap, if those are all good look at the gasket between the engine and header.

The car is less than 6 months old. Its never been stored for a long period of time. If I know I'm not going to run it a week or two I drop some after run oil in the engine. I don't think it's a tuning issue as much as a fuel supply issue. I just replaced the header so the gasket there shouldn't be an issue.

I'll have to comb through the feed fuel line and see if there is a leak. Along with the fuel tank.

Any further ideas?

Thanks again

 

[REVO-5309]

U have to richen up when u increase nitro. But sounds like ur tank has a leak

 

[MotoGod]

Depends on the fuel. I have changed in the past a few times and some fuels required more tuning tweaks than others....but it's a per engine basis kind of thing.

If you have no fuel flowing when you are priming, you have a leak in your fuel system. Could be bad fuel line, could be bad pressure line, or could be a leak in your tank. I would replace the fuel line and pressure line and see what happens. That's a cheap fix.

 

[Greywolf74]

I would replace the back pressure line from the axhaust to the fuel tank. If that doesn't work then I would check that the fuel tank doesn't have an air leak. most common area for them to leak is around the cap seal. Thats the two main things I can think of to do/check. I'm assuming you're already aware that you have to retune when you switch nitro % since you set the needles back to factory. Not that that fit the desciption of your problem...

 

[danarosetti]

I replaced the two lines and still no luck, so I'm guessing it is the tank. Hoping it's not the carb. The cap to this tank really doesn't seem to tight of a fit to begin with. I'll update when I figure out what it is. Thanks for the helps folks. Love this forum!

 

[danarosetti]

Tore the tank out and did some testing to see if there was a leak in the tank and or lid and to no avail. I did the soapy water trick and no bubbles came from any seams or the lid. As I stated, both fuel lines in and out are new and have no leaks. How would I go about testing the carb for leaks?