Fox 15 Question
 

Hi, I am putting a [new/old Fox 15 BB] on a Lazy Bee. I cleaned up the carb and I am ready to bench run. Anyone no of the initial needle settings on this model? I downloaded a manual but it had no suggestions. I could probably figure it out but its acting a little touchy, and I thought I would ask. I may have to go back thru the carb. Thanks
Keester

RE: Fox 15 Question
 

It's been a while since I ran a Fox .15. But if I remember you start out about 3 to 3 1/2 turns on the high speed and about a 1 1/2 on the low speed. If you have the older two speed carb.
Make sure you go to www.flightlinesolutions.com They have a lot of info on Fox motors at this site. Lots of trouble shooting info and fixes.
[&:]

RE: Fox 15 Question
 

Doug is correct.

PER THE INSTRUCTIONS:

3-1/2 turns out on the HS needle
1 turn out on the LS needle.

This is a rich initial setting. Assuming the motor is broken in, it should be easy to set the
HS needle for peak rpm, then adjust the LS needle for a good idle/transition.

GREAT little motor!!!!!!!!!


(Pssst....don't forget the castor!)

'Race

RE: Fox 15 Question
 

The procedure for adjusting the carburetor on your Fox .15 BB depends on which carb it has. Go to the site Doug recommended but use this link:

http://www.flitelinesolutions.com/carbs.html

Look at the photos of carburetor's and determine if your engine has the "Early 2-jet carburetor" or the "MKX Series Carburetor". Either one could be on your engine (depending on when it was manufactured).

If you have the "Early" carb, the procedure is exactly opposite from the way most carbs are adjusted - you must adjust the LOW SPEED NEEDLE FIRST.

Fox engines are good engines - if you follow proper procedure. A lot of folks try (tried) to adjust their carbs like other engines, then when they couldn't get them to run right, declared them "junk".

RE: Fox 15 Question
 

Good point on the carb "vintage".....BIG difference.

'Race

RE: Fox 15 Question
 

Thats really a lot of motor for a lazy bee. It will certainly be heavy and the bee will not be lazy.

RE: Fox 15 Question
 

The Fox .15 weighs 1oz more than an OS .15LA. An ounce is an ounce to be sure,
but if that's all it takes to break the bank....the plane had other problems.

The Fox will last a lifetime with a little care.

'Race

RE: Fox 15 Question
 

Not sure but I think the Fox .15 BB schnerle had only one carb design, and it has its own unique design not shared with other Fox engines.

RE: Fox 15 Question
 

Nope, there were two.

The old Two needle carb, and the MK-X introduced sometime later.

Here they are.

'Race

RE: Fox 15 Question
 

Pretty sure the top carb was on the older .15 baffle BB engines and the earlier .15 schneurle bushed engine. The lower carb was used only on the .15 schneurle BB. Although its called an MKX, it really is its on unique design.

RE: Fox 15 Question
 

Are you sure? I don't remember the Fox .15 baffle ever having BB's or a flanged carb mount.
Perhaps I missed one. :)

RE: Fox 15 Question
 

The carb on my .15BB schnuerle looks like the bottom one, only mine has a rectangular mounting flange at the bottom. It's a good engine, mine runs like crazy, as do my other Fox engines. I sure miss reading old Duke Fox's articles in the mags Yep. As a matter of fact, statements about them being "junk" are sorta what got me started with Fox engines. I was just stubborn enough to buy one just to irritate the hell out of a guy who told me they were junk. My little .15 BB is still running, iron piston and all, still runs rings around his OS .15 too.:) He doesn't refer to it as junk anymore, just mutters under his breath when I flip it twice by hand and go fly.

RE: Fox 15 Question
 

The old-style 2-jet carb. appeared on the first 15BB, which was a special rear bearing, front bushing hybrid with the ball bearings running directly on the crankshaft (no inner race). This version was only available for a few years before it was changed to a more conventional dual ball bearing design. A conventional bushing design was also introduced at about the same time. Both BB and bushing models used the old 2-jet carb. The .15's were the last Fox engines to get a carb. update to the MKX series, which occurred in the early 80's. The new carb., referred to in Fox literature as a "Series 15 Mark X", did not have the flat mounting flange and Fox employed an adapter to mount it to the BB engine. (By this time only the BB version of the 15 schneurle remained) As well, the old .15 baffle engine was also updated to the MKX carb. in the last few years of its production. The crankcase on the baffle engine was modified so that an adapter was not necessary.

The Fox 15's, both schneurle and baffle, have been among Foxs' most successful RC egines. All produce excellent power and throttle nicely. No modifications of any kind required on these. Just be sure your fuel contains some castor, and fly happily year after year.
Too bad the baffle piston version is no longer available. Compact, and super light, it would be perfect in a model like the Lazy Bee.

RE: Fox 15 Question
 

The Fox baffle motor which is one of my favorites dissapeared simply because the dies wore out. Remember someone said that Fox Motors had sold over 50,000 of them in just the first few years of production. The 15X motor was introduced in 1965 and continued to about 1994 so you know that there were a tremendous amount of them made
The 15 BB version is really in my opinion coupled with the Fox 25BB the 2 best motors in the Fox stable, light and powerful enough to satisfy most of the sport flying crowd.

RE: Fox 15 Question
 

Dennis,
The Fox .15 first appeared in about 1958 as the "steel fin" version. It came in a brownish colored box and I THINK it had the "X" designation. Sometime later they switched to the "slant plug" version with the drop-in liner. Don't remember the year. Perhaps that is the version you are thinking of. All of my Fox .15's are in CL version up to the schneurle when I have them in CL and RC (both bushing and BB).
I saw a baffle Fox .15RC on the bay in the last couple of days.

George

RE: Fox 15 Question
 

George,
Yes your right in one respect. The first Fox 15 was the Rocket 15 and had a straight plug and steel fin cylinder and was really geared towards sport and lower powered stunt.
The 15X was a completely different design with a drop in liner and of course the different head with the slanted plug. It was a much more aggressivly timed motor and was probably geared more towards 15 sized combat planes .
Really the X was much faster then the steel fin, it also was a little more long lived.
Thanks Dennis

RE: Fox 15 Question
 

Happy to find that the great running little Fox 15bb on my lazy bee is a good combination. I can slow to a crawl [especially with a light wind] and it will wind up to a pretty good clip. I know that the Fox 15 dosent like to be lugged with a big prop but after trying many prop combos and prop materials, I settled with a wooden Zinger 8X4. This thing runs forever on a tank too. I have always loved Fox engines since the 70s but this is my first .15 R/C. I really like it. With both needles I can make it idle and accellerate very well. Ive got 2 slant head bushing 15s on CL planes that are light and really cook. [Fast], Anyway thanks for your help.
Keester