I have been out of the hobby for a while and am just getting back in....
The engine is a mds 40 that comes on the xtra easy arf..
heres the problem.....
if I adjust the low and high needles the way your supposed to (2 1/2 turns out) it won't run at all........
so right now the idle is about 1 3/4 turns out and it idles perferctly....

Its a new engine and I know your supposed to break them in but I can't get it to run long enough for it to.....

at full throttle at the manufactures break in pre-setting it just dies... way to rich so if you lean it out a little you can get it to where it is perfect just screaming and I richen it up a little but it will run like this for about 30 seconds and die... If you touch it it is scorching hot!!!

now it will idle all day long but it just wont run at WOT? if you richen it up more to keep it from over heating it wont reach full throttle, it bogs and dies about 3/4 throttle??

Currently it has a 10x6 prop on it, and the baffle in the muffler removed...
Last week when I flew it for the first time, in the air it ran "ok" but it wouldn't idle, as soon as you cut it idle it would die.. Some of the guys at the field worked on it but still it would run really hot?? its like theres no Happy spot, its either hot or to ritch to run?? any help on this guy woulds be great... I want it to be running good when I go flying tomorrow..
so please post all your breaking in/tuning tips, thanks!

The best tuning tip on this engine for a newbe is to send it back and get your money back.

I know this within itself creats new problems but Horizon doesn't seem to want to fix anything before the customer gets it. They think they save money by letting the customer give up on the motor and set on tyhe shelf and never bother them?

The carb apparently has poor tolerences and the engine is never going to run right with that carb on it. Horizon might send you another carb if you call them? But it may not work good either?

Your best friend may buy a MDS 40 and it will be absolutely the best motor you ever owned. You never know how an MDS is going to run until you try it.

Some people on here buy up the motors like yours and manage to make them run right.

But you need to raise hell with Horizon.

Jim

well I'm not gonna give up just yet.......
I'll run some tanks through it more and leave it at the rich setting to see....

I just need some info on how to tune...

oh something else I dont know if it matters, but
in the air it doesn' seem to overheat and seize, just on the ground........

but it wasn't idleing in the air..
I'll fly it again tomorrow and see if anything has changed
thanks

I doubt there is anything wrong with the engine. For break in it should be set just to the lean side of 4-cycling rich. That means just when the engine breaks from wrough into smooth (screaming) 2-cycle running. The operating temperature of these, and other, engines can be over 300*F so you will get burned if you touch it. Today I just broke in a MDS .58 that I got yesterday, I did need to lean it out a little to get it into smooth running at WOT but not much.

Could be tank problems. It's funny how so many people refuse to believe there could be a problem with their tank. Also make sure the lines are good.

Well I actually considered that......
Thought it might be foaming or such so I ran it with the wing off (you can see the tank when the wing is off)
and there was no foaming or anything, and no bubbles in the line??
it does however get some bubbles in teh line when its right about to run out of fuel but thats pretty much normal....?

How long is your fuel line from tank to carb? If the line is too long, needle adjustments will be sensitive and it'll seem to be running lean and hot. This is not an uncommon problem.

Steve

what plug?
i used a os #8 plug and aK&B hp plug
it did not like the idle pulg for some reson?
also use caster fuel and no more than 10%
or send it to me and i will fix it or bye you a new one diffrent brand

its the same plug that came with the engine, no idle bar on it?

I've got some k&b plugs that are about 7 years old still in packaging un opened..... should I try a different plug??

The length of the fuel line is about 4-5 inches I would say...

Hi!
How much nitro do you use??
Regards!
JK

I just found out today my fuel is 10% nitro and 18% oil!!
also maybe where it was colder, I tried to tune it at the field again and here is what I got.....
I turned the needle out 2 turns started it up and it runs great!
no adjustments.....
if you go to WOT it take it a second the first time, hesitates then picks up rpms, sometimes it will go up the rpms smoothly, sometimes it will take it a second to smooth out and pick up rpms..

it was enough for me to fly it and this engine has plenty of power!! I was flying in heavy winds about a 1/4 throttle all day!
I'm not gonna mess with it any more till it gets a couple flights in, I guess these engines are just EXTREMLY picky until they start to break in a little.