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xtm 24.7 needle settings?

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A buddy of mine asked me to tune his Mammoth for him, i was reading that the lsn setting is 8 turns out,to me that seem's like way to much, is that the setting or is it something else?
 
Well I looked it up on www.RCDocuments.com ( Thanks FastEddy ) and it says three turns . It says to open the carb all the way with your finger . Then take a flat head screw driver and turn the lsn all the way in till it stops . Being careful not to over tighten . Then 3 full turns out and that is the factory setting . Hope this helps .
 
I've found that flush on the low needle works better than the "stock" setting. Then adjust in from there. The stock setting is far too lean for the carb; the slide won't close all the way, because the needle will make too much contact with the spray bar.
 
Thank's guy's, i gotta do a pullstart repair(crappy rope) then ill go from there.
 
If he has issues with the plastic backplate, before I forget, the Mach .26 metal backplate fits. However, you will need to do a little machine work on it.

You will have to notch it under the exhaust port to allow the header to fit on, then enlarge the countersinks for the screws, get longer screws to thread into the block, and drill and tap holes for the pullstart. This step (the drill and tap) allows you to fit an HPI pullstart to it.

You will also have to shim the starter shaft on the inside of the engine, so it will engage the crankshaft.

Sounds like a lot of work, but the end result is a metal backplate that won't fall apart if you over-tighten the screws.
 
Man... I didn't even notice it had a plastic backplate! That's an odd thing to do... I just put a 24.7 in my revo a few weeks ago. I had to go double check to see if it was plastic. It is... (not that I doubted you ;) )

When I installed my 24.7, the HSN was 1 turn from closed and the LSN was 3 turns in from flush. Needless to say, it wouldn't even start (thank God). I had gotten all excited and just installed it without giving it a once over. Then I set the HSN to 4 out and the LSN to flush. It was rich, but it started right away. Pretty much every engine I've had was rich at these settings... of course I didn't bother taking the manual with me. I'm much to smart for that!

Yeah, I'm an idiot. :thankyou:
 
Hehe, its' no biggie. I had two 24.7's; they're great motors. I sold 'em to a local friend of mine to put into his duratrax.

They're an SH-based motor, so any motor that's SH-based can share parts with it, to an extent. Examples are the GS B01 (backplate fits perfectly, but couldn't find one), the dynamite mach 26 (backplate, carb retainer, and screws), and a handful of other engines.
 
I had to put a little shim in between the engine and pull start on one of my 24/7's. The spool was rubbing and wouldn't let the string go back in. Loosened the bolts on it and it worked every time. I just made a little gasket out of a folder and stuck in between. Was because of the plastic backplate. You could see where the pullstart had been mounted.
Is that why you are putting the Mach .26 backplates on?

I remember the 8 turns out. One of my manuals said the same thing. I was a lot worse at tuning then. (if that is possible) Took it to the hobby shop and he made it worse. Seems like I got help here.

Good luck. They are great engines.
 
I set it to around 3-4 on the lsn and 3 1/2 on the high and I'm at about a 3-4mm on the idle,got it to spudder and kinda run but I'm getting there. Spent 3 hour's remebering why i love pullstart springs so much (remebering the days) needless to say the cord yanked and now were looking into a roto start.
 
Pretty close, digger. The actual reasons were that the plastic backplates' countersinks fall apart if you over torque them (which I have a tendency to do; don't want that puppy comin off during some big air).

That, and the metal bushing likes to back out from time to time. With the Mach .26 plate, at least it's all metal, so it gets rid of the bushing backing out factor. The only downside, as stated above, is you have to machine the plate slightly. But it's worth it in the end.

The actual credit for the idea belongs to a fellow board member on here, I can't recall his board name off the top of my head.
 
You can use the mach 26 pullstart. The drilling/tapping is only required if you want to run the HPI pullstart/rotostart setup from the S25/F4.1 engines.
 
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