Need Rolex!!!!

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Tdog

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Ok I'm having a little problem with my 3.3. I got some advice from you about a cutting out issue. I used your advice and nothing changed. So heres my issue. If i hit WOT the motor hesitates. If I ease into it, it will fly, but 50-70% of the time it will bog when it wants to shift to second. I ran it with a couple buddies with revo 3.3's today and mine had the best idle and seemed to run better as well, except for the hesitation. They thought it was a fuel problem. I have tuned every which way, making it run from 200 to 260. I have replaced the fuel line and resonator line. I have tried some nitro without after run oil. I'm thinking I have some kind of air leak or maybe something clogged. Have you ever had this problem or know of a couple of things I can look for. I think I'm going to rip the whole thing down and check the engine out. Maybe take it to a LHS. I just know it didn't have these problems after the first 1.5 gallons. I've tired tightening all the tuning screws down to see if there is something blocking them. Knowing what I do about engines I would have to say it is starving for fuel at WOT, but I can't run it any richer than what I have. Even at factory settings it has the problem. Something has to be blocking the fuel or some part has worn out. It is very frustrating.

I hope you or someone else has some insight.

Thanks for your time.

T
 
If you hit WOT off the line and it hesitates, you'll need to lean the LSN till you get a good take off. Your idle might pick up, so you'll also need to lower the idle screw. When it leaves the line with good pick up, then you'll need to lean the HSN till you get it running good.
Don't make any adjustments till the engine is up to temp, and try a couple of passes before adjusting it again.
 
I've tried a very lean LSN, but then it seems to hesitate at the shift into second. Rolex, what do you think about an air leak or do you still think it is a tuning problem. If it is a tuning problem; at factory settings I would tune the LSN first with this problem. That seems wrong. The thing that gets me is it never did this before.

Thanks for the help.

T
 
It doesn't seem to have all the right symptoms of an air leak, more like it's just not quite tuned. You need to make the adjustments in small increments and let it 'settle in' till you can see if it's changing for the better or worse, that's why I suggested you make a few passes after each change.

If you are at the factory setting, both needles will need to be leaned. I prefer to do the LSN, then the HSN, but you might try leaning the HSN till you get good WOT. Then you can start to lean the LSN for good punch off the line. Once the LSN is set correctly, you'll still need to tweak the HSN regularly for outside temp and humidity.
 
When I read the title I thought someone needed help with a shelf queen :green-grin:


It doesn't seem to have all the right symptoms of an air leak, more like it's just not quite tuned.


I agree with Rolex. The first thing I notice with an air leak is an eratic temp...normally continues to rise. Next it usually doesn't idle well which yours seems to be doing just fine. Like Rolex said it's a little out of tune.

Normally when someone is chasing a tune going from lean to rich the needles are really out of wack....Lean hsn with a rich lsn or vise versa. I would suggest setting your needles back to factory settings and start over. For me tuning is always easier when I start with the hsn, get it running good at wot then start working on the lsn for that powerful take off. Most of the time once the hsn is set the lsn is very easy to adjust because ever little adjustment is easy to notice. The one thing I have always done to a Traxxas engine is seal the carb neck and back plate, it has always helped!

Remember get it up to temp (200+)

Adjust one needle at a time

Make small adjustments using 1/8 turns

Once an adjustment is made it won't show immediately so run it for a few minutes before making another adjustment

if you get aggravated put it away for a while

It's a pain right now but if you take your time listen and watch you will get it and it will be worth it!

Good luck!
 
Last edited:
The one thing I have always done to a Traxxas engine is seal the carb neck and back plate, it has always helped!
R

Thanks for all of the help. I will start over and try again, but what do you seal your carb neck and back plate with?

T
 
Permatex silicon sealent worked for me. Run a small bead on the carb itself not on the engine.
 
What outside temp. is it when you run. Remember, you will have to tune the HSN slightly depending on outside temp. The colder it is outside the richer you will have to run. I have the same prob. with my 3.3 sometimes, just take the time and tune. After you run for a while look at the fuel line and see if there are any air bubbles in it. If no bubbles, i bet you can rule out an air leak.
 
it can be two things
1. traxxas fuel tanks are made kinda funky and the nipple on the bottom can be cloged with plastic, just take a needle or something and poke that stuff out.
2. the TRX 3.3 eats front bearings like crazy, try replacing that.
its definatly a lean bog, when the bearing goes out on mine i hit the throttle and it bogs right when it hits 2nd gear, no matter how rich you run it.
 
I will check the fuel tank. This problem came on "all of a sudden" that is why I was thinking it was something other than tuning. Is the front bearing part #5223?

Thanks
T
 

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