ORIGINAL: dant-RCU

Kingtoyota,

I have run Fox engines for 25 years and once broken in and setup they run fine for me.

Your engine has the Mark X carb (just for reference). If your carb is not passing fuel AND you have the high speed needle
open (say 4 turns) then I would say your carb is gunked up also. It is on the outside also. Here is what I would do.

Take the carb off the engine. Remove BOTH needles and soak the carb and needles in laquer thinner or, if you don't have
any, clean fuel overnight. You might want to move the throttle a little while it is soaking. After it has soaked blow out the
needle openings with compressed air (if possible) or use canned "computer dust off" or just really strong breath. Replace
the needles and open EACH needle 4 turns. Put a piece of fuel tube on the inlet and open the throttle full. You should be able
to blow thru the tubing. If you can't then your carb is still gunked up inside. Put the carb back on the engine and try to start again.
You should be pulling fuel. Once you get the engine running and it will be rich so lean out the high speed needle maybe 1/2 turn.
If you have to leave the igniter connected fine. Then set the LOW speed needle and you want it on the lean side if anything.
Once you have the low speed needle set THEN set the high speed needle. You want the high speed needle a tad rich (one or two
clicks rich from max rpm) Once that is set you might want to re-tweak the
low speed needle a tad but do not go rich with it. Contrary to what some might say it is NOT an idle needle, it is low speed
needle and actually meters fuel into the mid-range area.

Three things to remember here:

Duke Fox tinkered a lot and he had his very own ideas on carburation so always remember that.

Two , the Mark X carb needle threads are pretty coarse and a small adjustment will make a big
difference. Most carbs use a much finer thread.

Three, your engine will run much better with an idle bar glowplug. Especially in the attitude you have it installed. I am currently
running a Fox .46 in that config and it will not run well unless I use an idle bar glow plug. I had the same scenario with an older
Fox .78 and a newer Fox .74.

The previous advice on fuel is good. You must run some castor. Omega pink is fine and I use it but add 3-4 oz of castor except for the .46
which runs fine on straight Omega pink. I have never run more than 10 percent nitro in any of my Fox engines EXCEPT the .46 and it
runs fine on 15% , but my normal 2 cycle fuel is 10% anyway so that is what I currently am running.

My .05 here. There is a ton of advice in these forums - you just have to dig. Club Fox has a lot of info also.

Dan