Back to Basics

The dot on the cam gear was significant, the trick is to eyeball the dot to line up with the (imaginary) centre line of the push rod tube. A bit difficult as the gear teeth are cut diagonally (the gears mesh with the shafts at ninety degrees) and as the cam gear is lowered into place, it rotates, not a lot, but enough to make a difference between the engine just running, or running properly. With the engine sorted, or so I thought, I removed the Panic's very tired NiCd flight battery and fitted a shiny new replacement from Overlander (Buy British!). Some time ago I bought a pair of Spektrum AR 8000 receivers, I bought two to get 20% off. Wish I hadn't. I fitted the first Spektrum AR 8000 into the Panic, it bound OK, but there was no output to the servos. The second AR8000 was exactly the same. Seems I've been conned and the "Spektrum" receivers are a "lookalike" from a nasty Chinese outfit known as KoKo. Fitting a genuine Spektrum receiver cured the problem. Phew! I know I should be getting on with the Kadet, but its far too hot in the shed, and messing around with a newly acquired four stroke engine attached to a flyable Panic airframe, well...what's not to like?

Brian Jackson wrote: The dot on the cam gear was significant. A bit difficult as the gear teeth are cut diagonally (the gears mesh with the shafts at ninety degrees) and as the cam gear is lowered into place, it rotates, not a lot, but enough to make a difference between the engine just running,

Slight deviation - And people used to moan at me because of the time taken to set camshafts on the old Mercedes 250 & 320 diesels unless you have the expensive setting tools only supplied by Mercedes.

So, Brian have you got it running?

Have I got it running? The SC started easily and ran, I'd left the main and slow running needles alone, I'd flushed the carb with new fuel and blown it clear.
It didn't rev above 7600 and it wouldn't idle without the glow driver connected. I reset the slow running needle, I left the main needle at 1 1/2 turns open as the manual states. I re-set the throttle with a pin in the air intake. I removed the fuel tank and cleaned it and the fuel lines. The tank bung was a bit loose and had been leaking. The engine is an easy starter, but runs slowly and the idle is erratic. I changed the SC plug for an OS F, no change in performance.
The engine doesn't have much compression, but its ringed so that's to be expected. Can't really do much with it as its hot and the neighbours have their windows open and don't appreciate the beauty of a tuned engine on song.

Checked the prop this morning, its 12" X 8", should be 11" X 6" or 7". Might make a bit of difference to the running.

Glad you managed to salvage the SC. It's been parked up for at least 15 years Brian, so a problematic idle until it's fully awake is, I suppose, understandable.

Brian in my experience an old engine like that may well be suffering from the needle valve O ring going hard/brittle or being worn. I have had a lot of old (15 years+/many hours use) 4 stroke engines over the years that developed idling problems and sometimes starting to cut out at full throttle, whilst in the air, nearly all of which were eventually cured by replacing the needle valve O ring after checking through all the other things you have been going through with the SC and fuel system. Might be worth a look, it is usually evident by the outside edge of the O ring looking a bit flat rather than rounded.

Thanks for the tip Peter, bit much to expect an O ring to last fifteen years without deteriorating.

I must admit that I've done a lot of fiddling with servos, control horns and disintegrating pushrods just lately. This evening I found that the rudder servo on the Panic had gone U/S. It was a 3003 and fortunately I had just one 3001 in my junk box (apologies to Futaba enthusiasts, it was not intended as a slur on the excellent quality of Futaba products). I extracted the duff 3003, and I was pleased that I'd remembered to attach a pull cord to the servo lead before I disconnected it. The 3001 replacement had been tested before I fitted it, the servo horn a sort of pull/pull arrangement was left intact, but when I pushed it on to the splines of the 3001, all was not well at all. It was a few degrees out. I searched my junk box once again, unfortunately it didn't have any spare Futaba servo arms. I tried the original servo arm rotated one hundred and eighty degrees... BINGO! With new clevises, the rudder is now fully operational. One aileron pushrod had broken, the clevis was on the aileron and the other end of the pushrod was on the aileron servo, but there was no sign of the missing bit. I binned all the original pushrod parts and made up new ones. What do I do next? The Panic seems to be set-up ready to fly, everything works including the SC 52 fourstroke, which after the latest tweaks starts, runs and idles nicely. I visited Cashmoor today, I enjoyed watching the models and chatting to the members. I haven't flown a model for over a year, but I did get a promise from Simon O that he wouldn't laugh if I tried to fly the Panic. I'll bring a black plastic bag, just in case.

Good news then Brian. Rememered where Cashmoor is :dry:

Good job the co-ordinates were still in the SatNav's memory!