I have a new Fox .35 CL engine. It is about 20 years old, but before this year was never run. I am trying to break it in and I have a couple of questions. I am running it on a bench and using Byron fuel that is 15% Nitro.

First, in order to get it to run, I have to open the needle WAY up. On my other engine (McCoy .35) the normal flying range is between 2 and 3 turns open on the needle. On the new fox it is between 8 and 9! Is there anything wrong, or is this normal for this engine?

Next, when I run it, it seems to run very hot. When it stops it is literally smoking! Again, is this normal or is something wrong?

The last question that I have is that I am running it on a bench right now and when I am running it very rich as part of the break-in, it runs very smooth. I can look at the glow plug and it does not appear to be vibrating at all. But, as I lean it out closer to flying speed, I begin to notice some vibration. Not a lot, but as I stare at the plug, I can see vibration. I have ballanced the prop, but that didn't help. I would really like to get it running as smooth as possible before I mount it in my new plane.

Help and/or ideas on any or all of these questions would be appreciated!

Thanks,
Tom[img]i/expressions/face-icon-small-confused.gif[/img]

[img]i/expressions/face-icon-small-smile.gif[/img] See answer in CL forum....but CHANGE YOUR FUEL!!!!

as with all older foxes they have a steel piston and liner ,take the head off and put a little pearldrops tooth polish on the liner and spin it over with your electric starter,di this about three or four times clean it out and feel the resistance when you turn it over if it has loosened up a little put it back toghter and run it on the bech again ,the smoking will mean a burnt up piston and liner if it keeps up .this tip was given to me by duke fox himself so i now it works ,did it on my fox 60,what a screamer it is

GOOD LORD...Get RID of that fuel!

Not for this engine at all!!!!! This is a classic-style lapped piston/steel liner, bushing engine that was designed to run at relative low RPMs (<10K) and use High oil content (+/- 25% oil) straight castor fuel....

Lapped piston engines take a while to break in. These aren't "set it and forget it" engines.

Nonetheless...there is good reason that this engine has been in production for over 50 years....it really works good!

RE-READ the instructions.... Be gentle with it at first....it'll last forever.

Good Luck!