.15 T-maxx will not idle properly.

[thetmaxx]

I just got the truck out after about 3-4 yrs of not running, bought lots of batteries, and it started right up, but was too lean on the low end. started richening until it was way too rich and spitting lots of fuel out the carb, i was trying to find the right setting, but it doesn't want to idle with any setting. Brand new plug, and 20% traxxas fuel. Today it started right up, and kindda had a fast idle, i drove it around a bit to warm it up, and the idle started coming down a bit to where it's jerking in and out of gear, then it died, but only idled for about 3 seconds or so, maybe five. throttle response is still a little boggy, but i think it should at least idle by now, and not die. after it died i couldn't get it to restart. it has sat a minute now, it may start. it seems to need to sit for a minute before it will restart after it dies. i'm wondering if the engine is just tired, and something is seriously worn out in it.

anyways, any tips would be helpful.

 

[thetmaxx]

ok, i tried to run it again, got it started several times. BEfore it died, i did not notice any increase in idle, just an abrupt stop. one thing i notice is when it's hot it's hardest to start. it only seems to fire when i'm pulling it as fast as i can. I mean i'm ripping this cord very hard, wearing my self out. once it cools it starts easily. but when it's hot, i noticed it feels like it has very little compression. if i pull the cord slowly enough, it has zero compression can be felt. i went to my nitro plane, which hasnt been started in years either... .46 OS and no matter how slowly i turn it there is a lot of compression there.

I think i'm looking at worn cylinder sleeve/piston!? any thoughts? i know traxxas has the 2.5/3.3 trade up program and i think my LHS can do it in store.

 

[panpan]

yeh, sounds like a new piston and sleeve for you. I think it's actually quite rare to get no compression at all...

 

[thetmaxx]

I pulled the engine apart (on a hunch) I can see daylight around the piston in the sleeve. So I went ahead to my lhs, they didn't have the parts in stock, so they ordered them ($40) so it will be maybe mon - wed when my new parts come in. I think I'm going to pick up a new muffler while i'm there. probably a tuned Associated muffler for $21. Since then baffle in my tmaxx has a big melted hole. kindda makes me think last time it was running it was very lean...

Will running the muffler without the baffle cause issues? I've heard of people removing them... Also can anyone recommend a good low end rpm range muffler for me. the Associated one was just something the guy showed me as an example... I think TRaxxas has that tunned blue one, but the guy said it was for 2.5 i think. but on buytraxxas.com it shows it's for the pro .15

 

[panpan]

I wish i lived over there, all your parts seem really well priced.

Do these nitro pipes have baffles?

 

[thetmaxx]

both the associated and the traxxas seem to be a sealed design. like they dont un bolt in the middle like most stock pipes... does that mean they are baffless? Even my OS engines in my planes unbolt and have baffles.

regarding the prices, i checked buy traxxas.com and they list the piston and sleeve asy for $40. so I'm getting the same price as ordering from traxxas. I was really happy about that. towerhobbies.com had it listed for like $45+ shipping. I'm just disappointed the LHS didn't have much pro .15 stuff in stock. Some of their sales guys will kind of get into what ever you bring in, and want to fix, and some only want to sell new cars, new motors and upgraded aluminum parts.

 

[thetmaxx]

well, to follow up I put the new piston and sleeve in and the engine runs like brand new! I'm so happy to be driving it again!

 

[flandersander]

Not from expierence but I reccomend the traxxas resonator. It is aperintly better than the blue one. I have the 2.5 engine and only have the stock one http://www.btronics.co.uk/items/trx5152.JPG I heard the resinator was good but I have yet to try it.