O.s. 46 Fx Help!!!
 

Today I fired up a New OS 46fx to run a tank of fuel thru it before its maiden flight next weekend.
This thing was VERY sluggish on throttle up, and never seemed to reach max RMP.

Am I doing something wrong?

Does OS not like 10% nitro? (all I have at the moment)

Does low end screw need to be leaned out a little?

I am begining to think I should have got another Tunder Tiger......
cause this isnt right from what I remember of OS in the past.

O.s. 46 Fx Help!!!
 

You have to break it in you know, right. If you have it set rich for break in, it should definetly have a slow throttle response. You should run about 2 tanks through before you put it in the air, so it is reliable. My .46fx is the smoothest idling, most reliable engine I have. The only deadstick's I've ever had was when it ran out of fuel, and 2 on the first 5 flights.

Re: O.s. 46 Fx Help!!!
 

Definitely rich - both the high speed and the low speed needles, which isn't a bad thing when brand new.

When you have run a couple of tanks through, open the throttle fully, and slowly screw in the high speed needle. It should speed up, until you get to a point where it starts to die, then unscrew about 1/4 - 1/2 turn.

Then set the throttle to idle, and see if it's stable. If it is, open the throttle suddenly. If it splutters and finally picks up to max speed, producing a lot of smoke, the slow speed needle is too rich. If it dies immediately, it's too lean. Keep adjusting about 1/8th turn in this way until it picks up speed almost immediately.

OS engines are amazingly good at easily getting to satisfactory needles settings and sticking to them.

-David C.

O.s. 46 Fx Help!!!
 

So the 10% nitro makes no difference I guess?

Thats what I was thinking with any adjustments, but had to make sure.

Yes I know it has to be broken in thanks.

Its so rich it is collecting fuel in the muffler. At least that was my guess when I lifted the model to a nose up attitude and got a bath, and the pressure hose was disconnected when fueling, so it didnt get in there that way. I dont remember that happening before. will run another tank thru it this week.

O.s. 46 Fx Help!!!
 

You can also check the O.S. Max FAQ page:

http://www.osengines.com/faq/product-faq.html#q2

This is covered there.