swamper8

I have a stock TA MGT. (.28PRO motor) I'm having a dog of a time tuning it. I have the manual and started by setting the needles to the factory defaults. 2 1/2 - 2 3/4 CCW for the High speed and 6 1/2 CCW for the Low speed. That said, when the manual specifies a "turn" does that mean 180 degrees or 360 degrees? I cannot get the truck to stop stalling. As soon as I give it throttle it cuts out. I assumed that one "turn" means 180 degrees, so I set the low speed to 6 1/2 (3 1/4 complete turns) and then adjusted a full turn lean/rich (1/8th increments both ways) but did not have any success with my stall issue. Glow plug is Mccoy MC59 and I'm using 20% Traxxas fuel.

1QwkSport2.5r

One full turn of the needle is 360*. Turning it 180* is only halfway there.

swamper8

So if that's the case, I turned my low speed screw out a full 6 1/2 (360) degree turns and the needle almost seems like it's going to fall out of the engine. Is the head of the low speed needle supposed to protrude past the casting of the carb.?

nitroexpress

Although 6 turns sounds like a lot, the pic in the manual seems to indicate the needle is basically flush (or close to it) with the housing.

swamper8

Right, so there's an inconsistency here. If the manual shows flush and instructs 6 1/2 turns, but my needle is protruding/almost out at 6 1/2 turns, I would then think that the definition of a turn is not a complete 360 degree rotation but a 180 degree rotation. So my confusion remains......

nitroexpress

The manual shows examples of 1/8 and 1/4 turns. One full turn is 360 degrees (in the manual and otherwise).

It is important to pull out the slide a bit while trying to find "the bottom" of the needles engagement. If you don't you could damage the needle tip. Or you will get an inaccurate starting point. Running needles full in and then out multiple times can damage the O rings (esp if they are dry). That's why many engine guru's give needle settings as a function of a flush setting, One turn out of flush and etc. Your LSN probably wasn't fully in when you started going out 6 1/2 turns.

cbaker65

My pro 28 always ran sweet with the hsn at 2 1/2 turns an lsn at 5 1/2 turns out,but
then again,got to consider your area.
That perticilar engine was always easy to tune,an reliable.
Make sure that your fuel system is good,an you have no air leaks,otherwise,you will never
get a proper tune.
The Guy's are right on what was mentioned.Phisicly open carb up by hand,an turn the lsn all
the way,an then count your turns out.5 3/4 to 6 is about flush on the 2 needle carb.
However there maybe a new version out that has the 3 needle...
I have the old 2 needle version,a 3 would be a mix meter setting.

swamper8

Thank for the detailed feedback but I'm still at a loss. I opened the carb manually and then bottomed out the needle (lightly) but unfortunately it only appears to have gone in an extra 1/8 Turn at the most. Backing the needle out even only 5 1/2 complete turns leaves the head WAY out of the carb. If I bring it out 5-6 "turns" (half turns) it brings it out just past flush, which seems to be where it needs to be.......but no longer meets the definition of what everyone else thinks is a turn. (360 degrees) Outside of the needles settings I'm afraid this engine might just be just tired. It is the older two-needle version

cbaker65

Does you carb look like this...This one is the origial basic 2 needle carb.

swamper8

Yep, that's the little bugger. I'll try and post a pic of mine tonight with the LSN out 6ish complete turns.

1QwkSport2.5r

I've never seen a users manual that stated to set the low speed more than 3 turns out and high speed needles rarely more than 5-6. To the OP: it's clearly obvious you have your needles mixed up. The idle needle is in the carb slide which would get backed out 2-3 turns and the high speed needle is on the fuel inlet which would be backed out 5-6 turns or whatever is close. These "factory settings" are only highlighted if the settings are grossly out of whack.

swamper8

Here's the manual for the engine. Look for yourself, Page 2. I don't believe I have the needles mixed up, I'm looking right at the photos.......http://www.teamassociated.com/pdf/ca....60_manual.pdf

1QwkSport2.5r

I think the manual is printed wrong. Try opening the idle needle 3 turns and high speed 5 turns and try starting the engine. If the manual states 6 turns on the idle and the needle is falling out at that setting, obviously that's wrong. Without a doubt, one turn is 360* rotation of the needle.

swamper8

OK, well, I'll try swapping the turns for the HSN and LSN and see if I get anywhere. If it were a manual misprint, wow what a misprint. I would also hope by now they would have posted a corrected version. That is right off their website. But anyways, I'll report back.

1QwkSport2.5r

If the engineer/designer that designed the carburetor actually wrote the manual, it'd be a different story. Sadly most manuals are short a few (a LOT) of details.

swamper8

OK, well PHEW, mystery partially solved. I can't believe I'm the only one to have missed this but I couldn't find any other posts with people having the same problem. I found a different print of the manual online with DIFFERENT photos. I for the life of me can't figure out the difference between the two manuals, they both look like they are for the .28 PRO Associated motor.

Here's the NEW manual, it indicates the LSN is on the end of the thottle slide WITH the boot:
http://www.teamassociated.com/pdf/ca....28_manual.pdf

and here's the manual I was following which shows the LSN as on the end opposite the slide. (closest to the HSN)
http://www.teamassociated.com/pdf/ca....60_manual.pdf

So now I can adjust the HSN and LSN correctly. My only problem now is that I was playing around with the "false" low speed needle so much (second link) i don't know what it's for or what to set it to. I don't know if nitro motors have a "main jet" like a lawnmower/snowblower does and if so, is this the main jet? Maybe I should just screw it in until it stops? It's long/pointy and extends into the carb throat just like the main jet on a small two stroke engine.

*EDIT*
It was too late to be blasting around my neighborhood but I reset all the needles per the newly found manual and did a test fire in my garage. It's definitely better. started up rather quickly. stays running, doesn't bog or stall when I snap the throttle. I will tweak it tomorrow. Very happy but this was ridiculous.

cbaker65

Glad to here you got somewhere...
I love the pro 28's they are by far one of the easiest engines to tune,infact,I swaped the ofna 21 carb out
for the 28 carb,an my ofna 21 is way better to tune,an keeps a tune.
So is yours the one with the Lsn in the throttle?

swamper8

Yup, its technically in the throttle. The needle I was originally adjusted on the other side is what the low speed needle butts into inside the carb throat. So they kind of work together. I think I could turn each one three turns if I wanted. Only the throttle slide needle can be turned 6 1/4 turns without practically falling out. Thanks for everyone's help!

cbaker65

Yea,the carb that I showed you is the first gen carb,which is way easier to tune,an thats is probably
where the confusion came in at with the manuals.
The first gens came on the some of the first Mgt's monster trucks.I have several.
Ive also gave most of the carbs away,the one I showed is the last one I got other than the one
that I have on my ofna 21.I think they also used them on the Ae 21 engines..They are actually
produced by Thunder tiger....

nitroexpress

What you were originally adjusting is called the mid range needle. Which is technically (as you say) the seat for the LSN. Most manufacturers will caution not to adjust this. If disturbed, set to flush.