Need help with Maxx just turning full at rendom

[barneyz71]

I purchased a used T Maxx and I have an issue with it just turning full either way at any given time. I have changed the batteries in both the transmitter and the receiver and it still happens. It is the TQ3 transmitter. Any idea what I can check. It has also gone full throttle a few times at random.

 

[Rolex]

The best thing you can possibly do is lose that TQ3 and get a Flysky 3 channel radio. It's 2.4 Ghz with fully adjustable settings and any new trucks you buy will only need a receiver paired with the radio.
Click this for a good deal

 

[barneyz71]

So it is most likely the transmitter causing the issue? I was going to try a traxxas 2.4ghz 2 channel radio this weekend to see if it was the issue. I could also buy it if it works as it not being used. Will a 2 channel even be enough for the T Maxx?

 

[Rolex]

Sure, a 2 channel is all you need. Any 2.4 Gig radio is better than the old, outdated, untrustworthy, interference prone stock unit.

 

[barneyz71]

Thanks Rolex!

 

[Rolex]

Sure thing. Keep us posted, and welcome to the forum.

 

[barneyz71]

Well I received a 2.4ghz transmitter and receiver and it fixed my issue. The truck drives great now. I now just need to work on getting it tuned correctly.

 

[Rolex]

Glad to hear that. Let us know what the tuning issues are.

 

[barneyz71]

Ok... I'll try to explain it best I can. For starters it is hard to start and keep running. I have to pinch the fuel line on and off to keep it from stalling. If I keep it running long enough it will stay running and run ok. Then I can drive it for a bit and and after about 10 minutes it sometimes stalls. If I check the temp at the glow plug it is never over 220. Then it's back to the same ole story of pinching the fuel line to get it running. It smokes pretty good so I don't believe it is lean but it doesn't take off as hard as I would expect. I have adjusted the clutch where I think it's set right but it just doesn't pull off the line. My Revo will absolutely blow the doors of the T Maxx.

 

[Rolex]

Getting a poor launch is usually a sign of being too rich on the LSN. Start it and just putter it around till it's up to temp before making any adjustments.
Lean it only slightly each time. Treat the needle like a clock and don't go more than one hour. Then putter it around to clear it out and see if your launch improves. If it does, lean it a little more and try it again. Keep an eye on the temps since being TOO lean on the low end will cause a rapid overheat that you can't bring down with the HSN.
When you have a good idle and a good launch, that's when you start to wind it out and make similar adjustments to the HSN.

 

[barneyz71]

The thing that gets me is when I pinch the line to shut off the engine it rev's up almost instantly and shuts down pretty quick. That leads me to believe that it is lean on the LSN but yet I need to pinch the line to get it started. Doesn't make sense to me.

 

[Rolex]

What happens if you plug the exhaust with your finger while trying to start it?

 

[barneyz71]

That does help get it started but it wont stay running without pinching the fuel line. Once it is warm it stays running fine at idle.

 

[Nitro4910]

Have you checked over the entire fuel system for leaks?
Starting at the header seal and working your to the carb?

 

[barneyz71]

I have not but I think you are on to something here. I was thinking the same thing... I must have a leak somewhere.

 

[hotrodrob]

1. Don't overlook the fuel tank

 

[barneyz71]

1. Don't overlook the fuel tank

I ordered a new tank and carb yesterday. I also pulled the carb apart and cleaned it but it didn't seem to help. I am going to try and find a carb rebuild kit and some new fuel hose today at my LHS. If that doesn't help I will try the new tank and carb when it gets delivered. I will get this thing running correctly if I have to replace or rebuild every part on it. I will never give up!

 

[barneyz71]

Well I picked up a carb rebuild kit and some fuel line at the LHS. I also picked up some RTV at the auto parts store and sealed my engine. The truck is running so much better. I don't know if the problem was the carb or the engine but I'm happy it's running like it should.
Thanks for your help guys.

 

[hotrodrob]

Glad to hear all is well with it dude,..air leaks are fairly common with these engines, and will cause anywhere from a minor issue to a full on untuneable engine