Old Fox 25

Pat Frangella, one of my flying buddies, asked me to post this question for him.

He has an older Fox 25 with the removable venturi and spraybar. He says it is something like an inverted cone.

He would like any recommendations on how to get good runs out of this motor in stock configuration.

Anybody out there that can give Pat some help?

Well it sounds like it is the mid 70's fox 25.

I have a few of them, they are good sport engines. The do not like 4-2-4 runnng, a wet 2 works fine. 8-6 or 9-5 9-4 light prop. Some will say that the venturi is too large, but I never bothered. Use lots of castor in your fuel. They do vibrate.

make sure the 2 little screws on the venturi are tight.

Ditto on Dave's comments. It's a 4 bolt backplate, right? I stuck a 1/4" tube in that venturi about 1/2" long to bring the intake up above the muffler lug. This so you can choke it.
On another, I removed the venturi, cut the cone off, JB Welded a 1/4" brass tube, 1"long into the the flange mount and bolted it back on. It runs the best but is more work.
Keep you eye out for the old, old 3 bolt backplate Fox 25 and 19. They can run either a wet 2 or a 4-2-4 break. And they are lighter.
Happy Landings

Although I am frequently wrong, I believe that Tom Hampshire has fixed several of these....he did one for me that is terrific, and I believe that he did the engine that powered Bob Hunt's "Friskey Pete"?

They are good motors....Tom saws the venturi at an agnle to make choking easier.

See Ya

Dave, John and Peabody:

Thanks for the replies. I will print them out and give them to Pat when we fly this weekend.

John, I can vouch for the old three bolt backplate 19s. I am powering my Testors Senior 29 with one and it 4-2-4s really nice and pulls it through the OT pattern on 63 foot lines in the Kansas breezes (gentle ). 9 X 5 Rev-Up prop.

Bigiron