My buddy has a tmaxx 3.3 that we just can't keep running I have a revo 3.3 and a tmaxx 2.5 and both run great but his I just can't keep it running. I have reset the needles to factory I have tried to tune it but it just won't idle. We can get it to idle ok but then after a few high speed runs it will not idle right if you don't give it a little gas it dies. It has great power off the line and top end and the smoke trail looks good so I don't think his piston/sleve are bad. The temps run around 245 or so I'm pretty good at tuning but I can't figure this one out. He did replace the carb for some reason but he rechecked all the o rings and they are all good, the clutch is good, slipper is good I can't figure this out. Any advice will be appreciated thanks
Does it start die, after its warmed up?? Is it easy to start right back up when it dies and still warm? Do you need it to cool down before it will restart? Was tuning done with a half tank of fuel, and the engine at operating temps?
It is hard to start all the time not just hot and it was tuned when it was warm 200+ degrees tuning started at about 3/4 tank cuz we had to let it warm up first. I'm wondering if it's an air leak somewhere cuz like I said I have MY revo3.3 and tmaxx2.5 running great easy to start great power start east after they die I just can't get his tuned so I'm starting to think it's an air leak somewhere. A while back he broke a clutch cuz his slipper was to loose and he took it to the hobbie shop and paid them to fix it(he didn't think I could do it but now he has seen my trucks and trusts me) at the hobbie shop the way they got it running was pretty much no idle they cranked the throttle trim way up and it would always creep forward and ever since then he has had problems. Do you think the piston/sleave got shot after that? Like I said it has great power will wheelie forever and fast.
Sounds like you know what you are doing and tuning does not sound like it is that much of an issue. Turn the throttle trim to "0" and look over the clutch to make sure that it is in good shape and the spring is not stretched and the bearings spin freely. If those are good then onto air leaks (which may not be the case since you have good temps, but a rich mixture could hide them): maybe there is a small split in the fuel or pressure lines, the o-ring on the tank lid is not sealing, the coupler between the header and pipe is split, the head has a shim under it and is secured to the block using a star pattern to tighten it...
Just in case the hobby shop may have torn the engine apart, make sure the cutout on the piston is facing the carb and all the o-rings are intact.
I frequently say there are four things to make an engine run: fuel, air, compression and spark. If one of them is gone or weak, then you found your issue. I would say that spark/glow is the easiest to check, then compression. The other two are a little more involved.
Go through that engine and its accessories very carefully. Touch and inspect every part of it.
The Super Derecho
Clutch is good, fuel lines are good checked them to. I will have to check the tank lid. There is mo oil or fuel coming from the header but I will check that. I might just pull the head to inspect it and the piston. I have never had to check for air leaks how do I go about doing that? I'm wondering if it's the carb he replaced I'm not even sure why he replaced it but it's not lined up exactly by that what I mean is if we put the body on the HSN doesn't lign up perfectly with the cutout on the body it's like it's twisted a little could that cause this?