Sport_Pilot

That one does nothing but prevent fuel from leaking out onto the engine. I did that and no change. The engine got messy enough from the fuel standoff and the tubing made it more difficult to tune. Works better without them.

Sport_Pilot

That was an engine made in the 80's. A time when Fox had to cut many strange corners to keep the price down. That was really not a QC problem. Fox made them intentially with a short taper and not very precise. They had in instructions on how to taper the needle for the proper mid range mixture with a file and sandpaper. Then they changed this and tapered them precisly. For a while the engines in stock had the older needles and the replacement may or may not be the newer version. Those MK X carbs actually worked very well, as well as OS or ST once the low speed needle was tapered. The only issue is that a small amount of fuel will leak fuel (it does not suck air in with muffler pressure).

This is not the modern Fox engines which are much more refined and probably much better than the current OS sport engines.

[email protected]

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put on a perry carb..

computermonkey

My Feedback: (90)

+1 on the Perry.

Sport_Pilot

A Perry carb would be a poor substitute for the Fox MK X carb. I have several and all need the idle disk adjusted from early day to afternoon. Also the idle disk can be quite sensitive. The Fox carb only need adjusting from spring to summer to fall, not morning and afternoon.

Sport_Pilot

Actually the old saw of putting fuel tubing over the needles came from a time when muffler pressure was not used and it worked on those. Fox engines do not need this when muffler pressure is used, though they will leak fuel from the needles. However, with remote needle engines this again becomes a possibility as the pressure drops below atmosphere acrous the main needle.

earlwb

Actually a lot of people didn't understand what was happening when they stuck a piece of fuel tubing on the needle valve. It wasn't what they thought it was doing. The fuel tubing was actually centering the needle valve in the seat or carrier. This aleviates the problem with false needle settings when you are adjusting the needle as it moves around inside the seat or carrier. Some carbs used a dual detent,others used a single detent, still others used a lock nut clampand there were needles that used a spring to try to keep the needle from turning. The single detent was usually the culprit as it allowed the needle to move around inside the seat or carrier. You could see this effect when you just barely touch a needle, do not rotate or turn it, and the mixture setting changes.

Now then with muffler pressure, if you look at a needle that could be considered loose, you can usually see fuel oozing out of it. The needle and carrier are not sucking in air right there, instead fuel pressure is pushing fuel out. So it isn't a air leak like a lot of people were thinking. What they thought was a air leak was the needle being able to move off center causing the misture setting to change. Of course the little Cox 1/2a engines could be a real bear to adjust as the spring tends to cause the needle to move back on you when you want just a tiny twist on the needle. But they even ooze fuel out of the needle and carrier too. Perry Carbs ooze fuel out of them too. Those engines with little tiny O-rings inside the carrier for the needle can ooze quite a bit of fuel when the o-rings are worn or torn, but most of the time the engine runs fine like that.

I have some engines, and not just Fox engines either, that leak fuel like crazy out of the needle and carrier but they run great anyway. But they had dual detents on them to help keep the needle centered. I have seen seen Supertigre engines with the clamping nut ooze fuel out of the needle and carrier too.



The remote needles have the risk of causing the fuel to vaporizein the long low pressure zone between the needle and carb.One engine brand I know of actually had serious problems with vapor lock like situations on their engines when they had the remote needle valve body cast into the backplate.When the engine got all hot, the bubbles would form causing the engine to run badly from the mixture changing so much. I remember guys cutting the remote needle off and mounting a separate needle off the engine to aleviate the problem.

iskandar taib

My Feedback: (5)

I use (thin-walled neoprene) tubing on the OS RC NVAs I use as remote needles because I use bladders, and if you don't, you lose a LOT of gas mileage. No sense carrying a couple of extra ounces of fuel on board in a match, or coming down early.

Iskandar

Sport_Pilot

Bladder tanks! And the older crankcase vented tanks. I recall checking for leaks by blowing into the line.

Don't you love the taste of high nitro fuel and castor oil? Yum!

1QwkSport2.5r

I have several engine brands, and of the 11 engines I own, only one leaks fuel from the needle valve. A ST S29 with the clamping nut on the needle. Even after setting the needle and snugging the packing nut down, it still leaks. The engine runs fine even though it makes castor stains show up on the head.

One of these days I'm going to pick up another Fox. My little series V .40 ate a circlip twice before being broke in well. It still runs but the idle is rich. If the current .40's piston/liner fit, I'd buy one and drop it in. It's probably not worth it anyway. Better off trading it in.

Sport_Pilot

Send it to them for repair. Explain the circlip problem. They may fix it for free. If not then trade it in.

[email protected]

My Feedback: (1)

circlip? trade it in on a os engine

1QwkSport2.5r

It's a 1983 series 5 engine. Rear ball race front bushing. Not made for many years. The Fox .45 uses the same piston and liner I think, but of the same vintage. I got a new P/L from a member here and wrecked it accidentally. I knew I should have gotten better clips but I really didn't think they'd come out. I was wrong. I got the engine for free, paid $20 or something for the new P/L. Not out much. I want an Eagle IV .60 anyway, so I'll trade the .40 in.


Guys that can't tune a Fox or a Super Tigre carb and resort to buying an OS are like the guys who buy mopeds/scooters. They can't handle a real bike.

So, no. I won't trade in for an OS. I want it to last longer than a year or two.

[email protected]

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i can tune any engine but i dont want to be all day at it so i buy a good os engi ne i have some os engines for 15 yrs now all run good>> i dont have time to mess around i like to fly ive been flying since 1945>> i know my way around>>

[email protected]

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not all make you wait call horizon one day and its on its way the next try hobby king to see how long u wait

Charley

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I don't think you could get OS engines in 1945. What were you using then?

CR

1QwkSport2.5r

I haven't been at it as long as you guys have, only 15-16 years. But I can say from my own experience with my engines, I can set any if my engines within 5 minutes of getting setup. My Super Tigres, Enyas, K&B's, TT, or even the Jett. Tune them once about 400-500rpm rich and they will run all day without needing a needle adjustment. The ST carb took me some time to figure out, now it's a breeze. The Sportster .65 K&B engines had bad K&B carbs. Replaced the drone carbs with civilian carbs and they run perfect now.

I know my way around too, but if I can't get an engine tuned within a max of 10 minutes, there's more problems than just tuning the carburetor. Sorry, I don't buy the fiddling with it all day crap. Either operator error (most likely) or faulty parts.

Just an opinion from a little whipper snapper.

What WAS available for model engines in the .40's?

Charley

My Feedback: (2)

Hi, 10 WK,

I wuz kinda funnin'. I seriously doubt if anyone was making model engines in 1945. Shux, we were fighting a war and raw materials were in short supply.

But, to get on thread; I never had to fiddle with my Fox engines from flying session to flying session. Once set they stayed set if I flew them at my home field;
barring seasonal changes. All I ever had to do was keep some castor oil in the fuel!

CR

1QwkSport2.5r

I know Charley. I was asking more literally what was around at that time out of curiosity. But nonetheless, a Fox is a Fox. Barring mechanical failure due to operator error or using crappy fuel, they will outlast the owner. Heard of too many people still flying Foxes that were made 50 years ago on original piston rings and bearings.

You won't see any modern OS outlast a Fox or an Enya. Maybe even the old SuperTigres.

[email protected]

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i said i had some engines for 15 yrs but i had os 91 ducted fan engines around 1988 k&b rossie i used to work for a wholesale company we sold everything in rc to hobby shops i used to get almost every new plane engine radios misc items till i went to work for a hobby shop then 10 yrs later i got my own shop for 5 yrs in with a nother man then i stopped and got a good job

[email protected]

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i got out of nitro engines and went into good gas engines cost less to run starts easy no trouble

earlwb

Fox engines are easy to tune and adjust. It was just people simply not reading the instructions. I haven't had any problems tuning Fox engines. The other issue people had was no patience for breaking in the engines good.

Yeah go buy that other brand that is pre-worn out so you don't have to break it in. Then when it does quit working, you can throw it away and get a new one as  they don't make parts for it or if they do have parts, the parts cost more than just buying a new engine. But then they really want you to buy new engines every year as they always come out with a new design that is supposedly better than the last model. Thus you don't have the old engine wear out on you then, Now then years ago they did used to make good engines, but somewhere along the line the marketing folks took over and they changed. Planned obsolescence and throw away engines became the norm. I do still have a number of the other brand engines but none of them are newer designs, they are all older designs from before they changed.

dirtybird

My Feedback: (5)

I bought a couple of new engines in 1945. They were made in Canada. I think the name of one was Hurricane. There were a lot of Brown Junior engines but I think they were made before the war.

[email protected]

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it seems like a lot of people dont have good luck with engines like we do here in california and i do have a feeling most of you dont know what your talking about

1QwkSport2.5r

If you want to overspend on your beloved OS engines that come out of the box broke in and half worn out, have at it. I think it's BS that because you can't tune a Fox that the resolution is to buy an OS.

Sorry, this youngster isn't buying it (and I am pretty sure I know what I'm talking about). But that's just my highly over-taxed opinion. Take it for what it is.