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two stroke .74 fox wont idle

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two stroke .74 fox wont idle

Old 03-09-2004, 07:43 PM
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cal.45acp
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Default two stroke .74 fox wont idle

I bought a fox .74 nib at swap meet last year, test ran about 6 mo ago, ran fine,idle,hi end and transition all good. Installed in just finished project and will not idle. this is what I have tried so far . 1. changed fuel tank position from 1/2 " below needle valve to exactly evan (needle valve is in body of carb, not remote) 2. changed fuel 3.changed glow plug,4.changed fuel tank 5.dissasemble carb and clean all passage ways (did find a little crud on needle seat) 6. since this is an air bleed carb , checked all passages they were clean 7. checked for air leaks around carb body, barrel etc. I'm pretty sure not drawing enough fuel at idle,runs fine at mid to full throttle, this is not my first air bleed carb very familiar on how to adjust this type of carb,suspect a small air leak why it wont idle, but ran fine 6 mo ago, not sure of age of engine, but wonder if crank seal has hardened allowing small air leak at low throttle,hi end is rock solid no surgeing at I'm stumped . any suggestions thanks cal.45acp
Old 03-09-2004, 10:53 PM
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jessiej
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Default RE: two stroke .74 fox wont idle

Go to www.flitelinesoloutions.com. These people are genuine experts on anything Fox.

jess (fan of foxes & 45s
Old 03-10-2004, 11:55 AM
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cal.45acp
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Default RE: two stroke .74 fox wont idle

Thanks jessiej, went to site you recomended, and they had the possible solution in their trouble shooting section, but I will have to dissasemble engine to be sure, will let you know in a few days as I'm heading to the field to fly right now. ps. I've been reloading for pistol rifle and shotgun for about 45 yrs, scratch an aeromodeler, and you will find someone who loves to tinker with things and find out what makes them work . cheers, cal.45acp
Old 03-10-2004, 10:20 PM
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linclogs
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Default RE: two stroke .74 fox wont idle

Try this link:

http://www.flitelinesolutions.com/

Jess' had an extra letter in it. Go to the link for carburetors to get the skinny on how to adjust yours.
Old 03-15-2004, 09:29 AM
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flicka5
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Default RE: two stroke .74 fox wont idle

Have a Fox .74 ABC that quits in the air almost every flight. The year before when new, it ran like a champ. First year good, second a bummer! Flitelines Solution says that the Fox .74's ABC wear the piston to sleeve taper fit out in just 2 to 4 hours of operation which my Fox has exceeded. This is why Fox quit producing the .74 ABC and only sells a ringed engine in this displacement. They suggested I put a sleeve and a ringed piston in to replace the ABC junk. I just bought what I need to do this on eBay, a bunch of used Fox .74 parts for the ringed version.

cal.45acp: are you running muffler pressure and is your Fox the ABC variety? Also, is the carb the newer EZ model?

When mine didn't quit it was great with loads of power
Old 03-17-2004, 08:38 PM
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phread59
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Default RE: two stroke .74 fox wont idle

A little off thread, but 45 acp is one of my fave's. Kimber Custom Target, And standard outdoor Bullseye. I am not sure but I believe Fox came out with a twin needle replacement carb for this engine. My 74 is ringed and has an air bleed carb, NIB. You may need to get the updated carb. 1911 forever.

Mark Shuman
Old 03-17-2004, 09:12 PM
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flicka5
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Default RE: two stroke .74 fox wont idle

I have the EZ carb which is the newest version for the .74's as of a few years ago. Prior to that time they used an MK carb which had two needles. You will note on FlitelineSolutions link above, they recommend a new redesigned head button to solve some of the running problems. A fellow in Canada is making these buttons to the FliteLines dimensions which are $20 including postage. His Email address is given on their Fox site. Flitelines also shows the dimensions for these buttons so if you have a lathe or connections, you probably could get one made or make one cheaper
Old 03-18-2004, 01:00 AM
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cal.45acp
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Default RE: two stroke .74 fox wont idle

The fox .74 I have is the newer version with ringed piston and new style carb, upon disassembly found straight grove in front casting as described on flitelinesolutions web site. they reccomend filling with J.B. weld, but I have some concerns about lubrication to front bearing, I think a better solution is to go to a sealed bearing, will post results when new sealed bearing installed. thanks .45acp cats almost always blink when hit between the eyes with a ball peen hammer
Old 03-18-2004, 11:55 PM
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RCFly
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Default RE: two stroke .74 fox wont idle

I have a Fox .74 Eagle IV, one of the real early versions. Bought it through it with an AMA coupon when they first came out. It would idle perfectly, transition to full throttle perfectly on the ground. When the plane got airborne, it was a race to land it before it would quit. I got one of the head buttons mentioned in a previous post and it ran much better, but would still quit unless I set it up slobber rich on the ground. I had access to a small lathe, so I turned out an adapter for a Perry Carb that I had lying around. When I installed the Perry, all of my problems went away ant the ol .74 is one of my best running engines.

RCFly
Old 03-19-2004, 07:04 AM
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flicka5
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Default RE: two stroke .74 fox wont idle

RCFly, was yours the ABC or ringed engine with the two needle MK style carb? Mine is the newer EZ carb which itself, also has problems. Talked to Duke Fox one time at Toldeo before he died about his engines and think I got him mad. His engines had a lot of good features and if you happened to get one that ran, you got a good engine. Unfortunately, I think he released too many designs before they were totally bug proofed and turned a lot of second buyers off. Anyhow, he was a stubborn, proud person who I don't think was receptive to ideas from other people as we all sometimes act. Had one of his .40 engines that I could not kill! Ran it till the rod bearings must have had .004/5 clearance with the crank, really sloppy, and still kept running well[
Old 03-23-2004, 01:07 PM
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cal.45acp
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Default RE: two stroke .74 fox wont idle

I talked to fox mfg. today and they said some engines were sent out with the grove cut to deep and in fact that those engines would suck air around the front bearing, they do not reccomend J.B.welding the grove due to loss of luberication to the bearing. I asked if a sealed bearing ( one side only) would be the cure and they said yes, but they haven't found a bearing that was narrow enough (.218) they say that most mfgrs. widen the bearing just enough to add seals. I've found 2 bearings on boca bearings website that may work, will post futher progress. cal.45acp
Old 03-23-2004, 02:09 PM
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Kmot
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Default RE: two stroke .74 fox wont idle

I have a ringed .74 that I purchased in 1990 or '91 and installed it into my hovercraft. I set it up right from the get go with a Perry oscillating pump. Anyway, it always started easy, ran great, idled great, transitioned great. Totally reliable and I probably put a couple gallons through it before I stored it away. Might be something to consider for yours, a Perry oscillating pump.
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