Problem starting tmaxx 3.3

[Stevie13]

Hi all. i'm having problems with mt tmaxx 3.3. i have trouble starting it. when i try to start it using ez start it tries to turn over but doesn't start and when it finally does strt when i press the trottle on the controller after about 10 mins it cuts out when i relese throttle and i'm back to square one. I've tried several needle setting including factory settings. I've also notices too much fuel comes out the exhaust and even when i lean it it still has the same problems. if anyone can help i'd be well chuffed as i'm thinking about giving up on traxxas as i never have any problems with my rush evo apart for gear box issues.

 

[Jacknifejuv]

Have you sealed the engine and checked compression ? The slightest air leak can majorly affect tuning . And is the engine old had its fair use .

 

[Stevie13]

the flywheel is a bit stiff hwen i try to turn by hand. just changed conrod to davis diesel one as my mates stock one broke inside his engine and wreaked his engine.

---------- Post added at 7:20 AM ---------- Previous post was at 7:19 AM ----------

i can feel the air from my exhaust from about a foot away. is that good or bad?

 

[theant]

the flywheel is a bit stiff hwen i try to turn by hand. just changed conrod to davis diesel one as my mates stock one broke inside his engine and wreaked his engine.

---------- Post added at 7:20 AM ---------- Previous post was at 7:19 AM ----------

i can feel the air from my exhaust from about a foot away. is that good or bad?

Good compression! Just a thought, did you check your glow plug to see if it was lighting up?

 

[Stevie13]

glow plug seems fine. i just done get it cause it was working last week fine. i even thought the weather has something to do with it but my mates works fine. I've never knew nything to be so tempermental as a tmaxx. i love the hobby but this cars draining me lol

---------- Post added at 7:28 AM ---------- Previous post was at 7:26 AM ----------

also if i managed to get it to run the full tank of fuel would last about 5 mins, thats how much fuel it's using.

---------- Post added at 7:30 AM ---------- Previous post was at 7:28 AM ----------

just a thought. i have put a resonator exhaust on recently from a revo. would tht cause me any problems. dont see why it should though but i'm just trying to think of possibilities.

 

[theant]

I went thru that when I first got my tmaxx, and nowadays it runs great, fires up every time I turn it over and goes thru 1 glow plug every 6 months. And you have good battery strength in your ezstart wand? one way bearing is still in good condition? Maybe you need to check your idle gap with the tx and rx turned on and brakes applied to make sure that you have the proper gap setting.

yeah, you might have to retune for bigger exhaust.

 

[Stevie13]

I've nerly went threw 5 liters of fuel used about 3 plugs in that time. traxxas super duty long. tried both mine and my friends ez start. i could keep it running aslong as i dont let go the throttle also it heats pretty quick and I've got about 300 burns on my hands from the exhaust lol

---------- Post added at 7:39 AM ---------- Previous post was at 7:36 AM ----------

would the owb cause it to cut out do you think?

 

[theant]

Almost sounds like you are running too lean. Maybe try a different glow plug. Did you check the throttle servo linkage and make sure that the servo isnt closing the carb when you release the throttle? Check your idle gap like I said above, it should be a 1mm gap (thickness of a credit card) with your brakes applied, it might be closing too much when you release the throttle.

 

[Stevie13]

i go threw too much fuel for it to be lean i think. also even when my idle gap is about 2mm it still wants to die on me. gotta keep the throttle pressed at least a quarter.

---------- Post added at 7:56 AM ---------- Previous post was at 7:52 AM ----------

I've tried my hsn one turn from closed to 6 vturns from closed. I've only tried my lsn one to abour 3 turns each way. i feel like phoning traxxas and giving them abuse lol

---------- Post added at 7:57 AM ---------- Previous post was at 7:56 AM ----------

i'm actually pretty good at fixing and tuning rcs but this one has me beat i think.

---------- Post added at 8:01 AM ---------- Previous post was at 7:57 AM ----------

i know it might be hard to explain but how stiff would you say the flywheel should be for good compression?

---------- Post added at 8:06 AM ---------- Previous post was at 8:01 AM ----------

you know the rubber washer that's on the base of the carb that fits into the engine to seal it. should the orange rubber washer be visable?

 

[theant]

When you turn the flywheel, does it turn fairly easily until it reaches a certain point and then tighten up and become hard to turn. I dont think that it should be really hard to turn, but there should be some resistance at the top of the stroke. So you put the needle to factory settings? I know you said you did, just want to be thorough here.
HSN: 4 turns out from bottom
LSN: Flush with slide body
Idle: 0.7-1mm gap (with tx and rx turned on and brakes applied)

2mm gap is too much to start with IMO.

Also, how are you priming the carb before starting? I always blow into the tubing that connects to the top of the exhaust and blow just until I see fuel hit the carb and stop, this way I dont run the risk of flooding.

As for sealing, I dont see the orange rubber washer coming out on mine, maybe it is causing an air leak. Check and or replace all of your fuel tank and fuel tubing and put tie straps around all of the bases of tubing where it connects to the fittings, seeing as this is a cheap and easy point to start checking for leaks.

---------- Post added at 6:56 AM ---------- Previous post was at 6:48 AM ----------

Have you had a look at this thread? This might be of some use to you.

https://www.rcnitrotalk.com/forum/showthread.php?t=60832

 

[Snook Man]

Your engine has all the signs of a piston installed backwards when you installed the new con rod...

Give it a look see. The cutout portion of the piston skirt must face the front/carb side of the engine or the port timing will be way off and the engine will not run correctly.

If the piston is backwards, make sure it is mounted on the con rod correctly also. The rod should have an oil hole in the bottom that also should face the front of the engine.

 

[brendonz4]

I'm 13 and i kno this it happened to me take the engine off and clean ur way port and try yo start it and if dosent work buy a new one tht i learned from my dad becuz my recently broke