Stock needle settings & Identification (Force 25)

[jedimindtrick.]

Hello there..
Need some help with my nitro engine..


It is a Force 25 (OFNA?) engine in a GV XT2 1/8 Buggy..it has been in storage for a few years and have just decided to get back into the hobby.
It seems it was never broken in properly (if at all), when turning the crank by hand it is very sticky at TDC..
So, I was planning to break it in properly , But I was unsure of the stock needle settings where, the GV manual is pathetic, so is the DVD..I looked up the XTM version but they use a different engine so that was no luck..
I needed the settings for all needles including the MSN as I wasn't sure if it had been moved or not, so I contacted OFNA and although he gave me the stock settings, he confused me even further when it comes to the Low and Mid speed needles..


I was under the impression that the needles where universal, the LSN is where the throttle is (on ALL engines/carbs) and the Mid is on the opposite end..but in the first reply he told me that Force engines should not have a Mid needle and it would be a first he heard about it..so I took some photos and replied, then he sent me this link: http://www.ofna.com/guide-tune-basics.html clearly showing Force engines having a Mid needle.
But what confused me is the labeling of the LSN & MSN - (B) is labeled as LSN and (D) as MSN..but underneath it has the Hyper 21 engine, with, what I thought, was the correct orientation of the needles.


Is this common? I know that they can have a physically different orientation design of the carb, like the throttle being on the right instead of the left etc..but can the needles be different? How would someone know this was the case unless they look up each engine they touch first?


Could someone please help me to clear this up?
Any help would be greatly appreciated.


here are some photos..would my labeling be correct no matter what the ofna page says?
https://www.dropbox.com/sh/h6nse8g9xdjmu0g/AAA6ZTjG_GpLaM9PH8UMNxjVa


P.s, the Stock settings I was told:
HSN: 3 to 3-1/2 turns out from closed
LSN: Flush with carb body
(low speed needles on older Force engines are not in the carb slide but on the carb body 180 degrees from the slide)
Idle: set approx 1mm air gap at the carb slide
Mid to be set flush, then adjust low speed as needed.

 

[Rolex]

Look through the following link...
https://www.rcnitrotalk.com/forum/showthread.php?t=60832

You'll find a lot of the information you're looking for. Don't hesitate to ask for advise if you're still having trouble.

"Sticky on top dead center" ?
You'll have a lot of compression up there as well as the tightest part of the 'pinch', but the word sticky confuses me. It might be gummy from sitting with old fuel so it wouldn't hurt to put a little new fuel in the glow plug hole and run the piston up and down to clean it out. Just make sure to get any excess fuel out of it before putting the plug back in.

 

[Reddog]

You have it labeled correctly in your picture. At least the first one. I would run some raw fuel through it without the glow plug in, turning it slowly. I would let that sit for about an hour then drain out the excess and turn it over faster to make sure it feels right. The I may try to start it. I usually start it with the LSN about flush and the HSN 2 1/2 complete turn out. This baseline has worked well for me in the past. Hope it helps, Shaun

 

[jedimindtrick.]

sweet thanks a lot..
Yeah, when I first pulled it out there was a lot of old oil left behind, I took the back plate off and sprayed fresh fuel in through the back and in through the top and cleaned it out, much better. Although it took me over half an hour with a magnet in the grass trying to find the starting pin that fell out lol..
I did manage to get it started, but had to open idle screw more.

What i meant by "sticky" was "tight" i guess, it would get stuck and required more force to turn flywheel, it is a lot better since I cleaned it out, but it was like this since I bought it, my starter box could not spin the flywheel (even with glow plug loose). I read or heard that this is normal for new engines and goes away when broken in properly, that's why I thought it wasn't done right.

 

[Rolex]

The cylinder actually has a taper to it, being tightest at the top. Proper break in expands and contracts the metals till everything starts to fit nice and smooth for performance running.
I'd recommend that you run several tanks through it using the proper break in method just to insure that you'll have a good engine with a long life.

 

[jedimindtrick.]

Will do, the new school heat cycling method should be the way to go right?

Also, that link you posted above is awesome, very helpful, thanks a lot!

 

[jedimindtrick.]

My temp is incredibly high 270+ all needles are flush and running in a small area few squeezes of the trigger never going above 1/4 throttle, cover off, fresh 20% nitro, LRP medium glow plug.
Would this be caused by an air leak?

 

[Reddog]

An air leak may cause a lean condition. I would open the needles about 1/8th turn and see what happens. Usually an air leak will make tuning a nightmare and cause an irradiate run.