3.3 Major Tuning Issues

[Ponch]

Hey, my 3.3 has been out of commision since the race for the cure. Yesterday I get the stuff to fix it, and today I run it. It won't start without about 1/2 throttle, and whenever I let off the gas it cuts out. The idle needle is all the way in. Completely.HSN is at factory, 4 turns out. I've been trying the LSN everywhere with no luck. Please help. I wanna race next weekend lol. Thanks.

[Mr. Tune]

Did you have it taken apart? Is the piston installed the right direction? The cutout at the bottom of the piston needs to be facing toward the front (carb side).

If it's not, it will do exactly as you describe.

Don't ask me how I know :o:

[firesprink281]

mash: my motor wont run mash:
also dont cover all the outlets on the carb and try blowing in it.

sorry i had to do it.

[thenewguy821]

Sounds odd... Just a thought. I had a similar problem with a Mach engine last summer. Take the engine out, and SLOWLY try to turn the throttle arm on the carb. If it won't turn, that's a good thing. The Mach I had wouldn't idle. When I took it out, I noticed the throttle arm would turn (I could completely turn the slide inside the carb). I found out the tip of the idle screw was broken, and wasn't opening the carb to idle.

[Traxxas_Junkee]

I talked to him on the phone and he said he could see that the carb was open with the idle needle. Tune, he broke the case on it so yes he had everything out of it. Matt, does it seem like it is flooding? Like when it starts does it have power or no? Is your starter box hooked up wrong? + is on the - and the - on the +? That would be turning your motor backwards.

[thenewguy821]

If the idle screw is opening the carb, AND he has had the engine apart, it sounds very possible that the piston is in backwards. When you look at the bottom of the piston, the "Skirt" only goes 3/4 of the way around. The part of the piston that doesn't go all the way down should face the back of the engine (Towards the backplate).

Someone else here (Names have been withheld to protect the innocent) had the EXACT same problem.

[Ponch]

If the idle screw is opening the carb, AND he has had the engine apart, it sounds very possible that the piston is in backwards. When you look at the bottom of the piston, the "Skirt" only goes 3/4 of the way around. The part of the piston that doesn't go all the way down should face the back of the engine (Towards the backplate).

Someone else here (Names have been withheld to protect the innocent) had the EXACT same problem.

Now wait. You say the cutout goes towards the rear, and tune says the front. Right now I have it facing the rear I think. So shall I switch it around and try again?

[Mr. Tune]

The cutout faces the front. I found out the hard way.

[thenewguy821]

My mistake... From the exploded view on Traxxas' site, the cutout goes towards the front... http://www.traxxas.com/products/nitro/tr..._views.htm

[Ponch]

Alright cool. As long as I know for sure lol. Thanks guys. +Rep for y'all.

[olds97_lss]

It does depend on the engine though, the cut out isn't always toward the crank. If I remember correctly, my orion wasp 18 had it facing the backplate. Looking at the parts explosion, there isn't a cut out towards the backplate, so it must be toward the crank. Then again, the pic just might not be an "actual" representation of the engine.

[thenewguy821]

That's true Olds, but Tune had the same problem when he rebuilt his TRX engine. He put the cutout towards the rear (Backplate) and his engine had the same problems.

[Ponch]

Aww man thanks guys! My problems are solved!

Tonight I got the piston turned around, fixed my starter box (I stood the battery up, but now it's laying down like it's supposed to) fired it up and tuned it. My idle needed upping and so did the LSN, and I haven't touched the HSN but it's at 4.5 turns out lol. Factory is 4 BTW hahaa...

It's flying now, and I don't even have full throttle! (I haven't gotten the new DX2 down completely yet, gotta change some stuff)...

So yeah, just saying thanks again for the help.

[rocco79]

Glad you fixed! That will teach you to take things apart that dont need it! LOL!!!!









BTW... In response to your sig line..... No you cant! LOL!!!

[Ponch]

Glad you fixed! That will teach you to take things apart that dont need it! LOL!!!!

BTW... In response to your sig line..... No you cant! LOL!!!

I needed to take the motor apart lol- didn't you see at the Race for the Cure that I busted the ears off the block and that's why I didn't even start my main?

Sig changed, is it better now? lol

[Michowski]

who's first and second? for longest revo?

[Ponch]

Tune and Tex....Is your truck that long too? I'll change my sig to the 4th longest if it is.

[Michowski]

Tex doesnt run the chassis, just the arms. I was just curious because I thought only me and tune had it and I was right.

[Ponch]

Ohhh....Alright so I'm still third lmao...

[Michowski]

congrats, il have a trophy for you next race were both at

[kevinF]

I have the 3.3 revo but not the setbacks

[Traxxas_Junkee]

Matt, I thought you had some kind of axels or something that made it a little bit longer too?

[thenewguy821]

I think he still has you beat on Length Ryan. I think he has the 3.3 chassis, which is 1.3 inches extended, isn't yours and Tune's only 1 inch extended?

[squirrel]

Come on boys lets quit measuring size here!!!!

[Ponch]

I think he still has you beat on Length Ryan. I think he has the 3.3 chassis, which is 1.3 inches extended, isn't yours and Tune's only 1 inch extended?

Naa, I have a 1 inch extended chassis.