Will a Fox 35 run on the test stand using Powermaster 22/10 ? I just want to see if it still runs. I used it last about 23 years ago ? I think then I used Cool Power 28 castor/ 10 Nitro ? I don't want to mess the Fox up if it will still fly a few more years but I kinda didn't want to buy a gallon of heavy Castor either. Oh well. cake and eat it too I guess ?

    It will certainly run on that. I wouldn't run it for long that way and for sure don't get it too lean, but a few minutes won't hurt anything.

    I don't think there is such a thing as Cool Power 10/28, if you ran it on Cool Power for more than a little bit don't be surprised if it's a little tired at this point.

    Brett

When I first got back into control line flying in 93, I had an old Fox 35 that I bought back in the mid 60's that had many gallons of Fox Superfuel run through it in a couple of planes. I did what you are going to do and had some Byron R/C fuel with I think 18% oil. I put it on the test stand and ran a couple of tanks through it running in a four stroke just to see how it ran. It did clean out some of the varnish buildup but it still had strong compression and I have flown it for years in several more planes. I do run Sig 5% nitro 25% all castor fuel in it for flying. That's my experience anyway.

Your fuel will be OK for bench running.
But your  TESTSTAND!  Ensure it's a wooden mount or have thin wood shims under the lugs.
If a Fox is bolted down hard to a flat test stand it can bind up severly because the Fox engines mounts are NOT perfectly flat. The are canted downwards a bit...
Enjoy!

Cheers, Paul

Will a Fox 35 run on the test stand using Powermaster 22/10 ? I just want to see if it still runs. I used it last about 23 years ago ? I think then I used Cool Power 28 castor/ 10 Nitro ? I don't want to mess the Fox up if it will still fly a few more years but I kinda didn't want to buy a gallon of heavy Castor either. Oh well. cake and eat it too I guess ?

Any help with testing the Fox would be greatly appreciated  

Here comes Summer,
Co-Cliff

Yes but why do it unless your only going to try it one time to make sure it still runs OK,  and by the way  Cool Power is 14.7%  oil  not 28%  so be careful running it in a FOX 35

There is a good article pinned at the top of this forum that goes into detail as to why.... below is a  small snipit from the article..

" For motors like Fox .35s, OS Max 35s or the old McCoy’s and K&B’s, use a fuel with 26 to 28% oil content; preferably half castor and half synthetic, up to 75% castor  is OK. These  motors have very small bearing surfaces, and are subject to much wear and heat, most are all plain bushing motors and most have unbushed rods. They need a lot of  oil  to help cool the engines. Since these motors run hot, they need  extra oil to keep them lubed,clean, and to carry out heat . If you have one of these that is  in very good  shape but, is  just starting to get some brown or black varnish plating on it, the synthetic mix will clean it  up for you, resulting in increased life.  Do not use the synthetic  blend in an old motor that has a lot of time on it with all castor fuels; the synthetic will remove the castor varnish off the piston and sleeve and will in some cases, leave you with the worn-out motor that had to start with.  Also always try to NOT use  prop shaft extensions with these engine, as it adds a  lot of  wear on the crankshaft bearing."

Cliff,
On thing you should check before firing up the old Fox you should check that the connecting rod is free to move on the piston wrist pin. To check this remove the backplate and grab the conrod and slide it back and forth. If it doesn't move you can take a heat gun and heat the inside of the pistion/wrist pin area then try to move it again. If it is still stuck you will need to remove the piston and wrist pin keepers (the C shaped wire clips that are in the groves in the piston boss then with the piston in a wood vee fixture (I have a small piece of 2x 4 with a vee notch cut down it) heat the rod end and carefully drive out the wrist pin. Clean off any built up castor with a green sottch pad, lub and reinstall. One good tip I read for installing the keepers is to install them with the piston/rod/ wrist pin assembly in a lunch size zip lock bag, this way if one pops you don't lose it. Once this is free you should be good to go.

Best,            DennisT

Better order a rear gasket before you remove the old one, chances are it will tear or crumble
while you at it look for any impact on the rear cover from the crank pin if the engine has been in the ground, if so check to see the crank is still true

Randy