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  1. #1
    RC Racer
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    Jato 3.3 Starts, Doesn't Idle

    Just purchased my Jato 3.3 and this is the first TRX I've had that doesn't idle on factory settings. I've tried leaning it out 1/4 of a turn and richening 1/4 of a turn. It still doesn't idle. If I give it 1/4 throttle, it seems to bog down and die. Not sure what direction to go in. I need to start the break in process...

    Temperatures are warm, so it's not that... Any ideas here?
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  2. #2
    RC Champion
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    Hey man i just bought my jato earlyer today too they are sick i havnt started my break in eaither so dont feel bad but anyways check to make sure your throttle nob on the controller is set in the middle and not all the way to the Right..Oh yeah when i took my air filter off to see the carb when i hit the throttle the carb didnt open all the way i had to adjust the little grub scew so make sure thats all set and opening fully and closing fully too... and just make sure everything is at factory setting like the low speed and the idle the high speed should be 4 turns out from closed, and make sure you didnt flood the motor too.. but other than that you are gunna have to keep tweeking it and dont make big changes to everything its a nightmare to get it back!

  3. #3
    RC Racer
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    Well, everything is factory. I got it to run through the first tank once I dumped all the fuel out of the exhaust. But now it won't run for the 2nd tank. It just won't run on it's own. It dies once I take the EZ-Start off. If I prime the engine by covering the exhaust for 2 seconds, it'll run for a couple seconds and die.
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  4. #4
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    Yeah that kinda sounds like there isnt getting enough fuel..umm is it realy cold where you are? if it is you will have to richen it..and how did the idle sound did it sound low or high or even just right when you did the first tank
    Last edited by Rich1101; 11-23-2007 at 08:17 PM.

  5. #5
    RC Racer
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    I richened it up and it ran for the second tank. Right now it's about 68F outside, but I start it in my garage where it is over 70F. It started to lean out right at the end of the tank though. I pinched the fuel line and it barely ran 1 second. We'll see how tank 3 goes. But I don't ever recall having this much trouble with the TRX 2.5 engine... Maybe this time I just got the break-in pains...
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  6. #6
    RC Turnbuckle Jr.
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    My 3.3 wasn't idleing but for a while and then I let it sit for like a month and now it works but it just has a low idle. You can try re-building the carb then replaceing the o-ring on the back plate, I need to replace the o-ring I think
    No more money for rc trucks I got 1:1 truck

  7. #7
    RC Racer
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    I got it all up and running, but I need to work on richening it more. It doesn't want to shift into 2nd gear.
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  8. #8
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    i dont think that has to do with richening it? Is there good blue smoke and if you put your hand infront of the Pipe is there alittle gas spitting out on your hand, if the temp is like 220 to like 265 you really dont need to richen anymore... how is it running now?? good is it idleing fine and reving good or no? whatever you do dont touch the transmission they are hard to get back to switch the right time.
    Last edited by Rich1101; 11-23-2007 at 11:11 PM.

  9. #9
    RC Turnbuckle Jr. icepick832's Avatar
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    Ihate to say it, but re-read the manual, and watch the DVD. Richer will not help it to shift, that would be lean. You shouldnt really be hitting second gear on tank 3. Tank lean is common. Tuning should be done after break-in of all 5 tanks, and only adjustments before, are to keep it running.Tune with engine at operating temp (usually takes 1/2 tank at the Ambient temps you mentioned) and half a tank of fuel. If you tune at full, you will notice a considerable tank lean issue, when its low on fuel.Pinching the fuel line should yield a 3 second run time with the engine RPM's going up slightly just before the engine shuts down.This is a low speed adjustment (lower on the engine, consult your manual) If it runs longer , then you need to lean it at 1/16'th intervals, doing a couple high speed passes between each turn. Shuts off right away, ruchen it using the same method

  10. #10
    RC Enthusiast
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    try going back to factory settings the top screw on your carb 4 turns out from closed the screw at the back of the carb 1 3/4 out from closed this helped mine out then after my break in i turned the top screw 3 1/2 turns out from closed and it ran great.

  11. #11
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    Guys, like I said, I got it all up and running. I should've clarified myself better when I said that. I meant, I got it all broken in.

    As for me adjusting 1/4 turn each way, I was doing that because it wouldn't even idle on the first tank... I'm no n00b to nitro, or TRX itself. I actually posted because I was concerned that it wasn't idling. All of my previous TRX nitros were able to idle and run on the factory settings.

    Anyway, I have it tuned much better now, but I can't really wheelie on demand... When it does wheelie, temps are close to 270F, but I don't want to run it that warm. Also, is the 2nd gear shift audible to the ear? On my Savage, you could definitely hear it shift and with the Jato, either I just don't hear it or it isn't shifting out of first.
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  12. #12
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    1/4 turn is WAY TOO FAR to be adjusting needles when it comes to nitro engines...ALWAYS tune in the smallest increment possible, ie: 1/12th or 1/16th of a turn...its easy to tune in 1/12th increments, just imagine the screw had a clock face around it...and a general "rule of thumb" when tuning and you lean out your HSN, you have to richen your LSN...this is because when you lean out the HSN it restricts the flow of fuel to the LSN, hence you have to richen the LSN to maintain a proper air/fuel mixture & reliable idle...and same applies when when you richen your HSN, but (opposite direction) you lean out the LSN to maintain the proper air/fuel mixture...so w/that said always remember reset carb to factory settings (<-- Click!) when your tune is way off and start re-tuning from there...in the following links there is "tuning guides" for nitro engines...they have really good info in them to aid you in the tuning process...and as for tuning yes the 2.5 & 2.5R & 3.3 are all tuned the same way...incase anyone was wondering...and always begin tuning after you have run through 1/2 of a tank of fuel to ensure the engine is at normal operating temp, and to prevent the dreaded 1/2 tank lean bogging...use a temp gauge for double checking your tune (if one is available, i find the Duratrax FlashPiont (<-- click!) works very well)...and DO NOT tune for a specific temp...ONLY use the temp gauge to make sure you stay UNDER 270 degrees...(Click! -->) Tuning Guide #1, Tuning Guide #2 & Tuning Guide #3 (<-- Click!)...and finally here is another usefull tip, you can "read" your glow plugs to verify if your tune is good or not...and as for "reading glow plugs"...you should do it after you have ran 4-5 tanks on a fresh plug...then take it out and "read" it...here is some more info on reading glow plugs (<-- click!) with illustrations...and it would be a good idea to bookmark these links for future reference incase you need them, they have allot of great info in them...the last one even goes through finding air leaks and getting that last percentage of the "perfect" tune on the second page of it...good luck!!!...
    "Growing OLD is mandatory, Growing UP is optional"

  13. #13
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    as for the wheelies it takes some time for them to become on demand...engine will "wake up" and be very powerful around 1/2 gallon of fuel being ran through it...and yes the gear shifting is something you can here if you listen for it...but it happens very quickly in like a second, maybe less...rpms will go from high, then drop just a bit and go back up and start climbing to even higher rpms than it was at in the first gear...almost sounds like a street bike when the rider quick shifts to the next gear just allot quieter...
    "Growing OLD is mandatory, Growing UP is optional"

  14. #14
    RC Racer
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    Redck1979, thanks for the advice but like I've stated before, I've got it running just fine. Man, I really have to clarify myself here. YES, I understand that 1/4 is a big difference in change with the needles. I tune in about 1/12 increments. But like I said before, I ended up going 1/4 of a turn, well for clarification, 1/12, 1/12, 1/12, in each direction with no improvements for that first tank. I finally got it running once I kept 1/8 throttle. It's been good ever since.

    I don't tune according to temperatures either. I just noticed that the powerband is a lot stronger (hence wheelies) when it's close to 270F. But I do not want to run it that warm. I always like to run a little towards the rich side, but I would like to see some wheelies.
    HPI Baja 5B - 23cc Fuelie |Sold: Jato 3.3

  15. #15
    RC Champion
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    yes i saw that you said you have it running...allot of what was in my long post is from a text file i have created for things i post regularly on these forums, its way easier for me to copy paste, then edit/add/customize post, instead of typing the same things all the time...just putting the info incase you wanted to look it over to familiarize yourself more w/nitro, and for any others that may want to take a look at them...
    "Growing OLD is mandatory, Growing UP is optional"

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