Super Tigre 61 setup??

[Tripler]

Hi
doe's anybody know the default factory adjustment for the idle screw on this
engine, and which fuel it runs best on,
The engine is in my new/old F1 carbon max which fly's realy nice (when it doe's fly) but I can't get it to idle ok, the clutch is a bit grabby so I need a steady idle.

The Super tigre manual say's four and a half turn's out for the needle valve as
a start point and says the idle screw is set from the factory,
Thats all fine and good if you, or someone else, has'nt touched the adjustment,, does'nt help if you need to start from scratch, ie. different fuel,,
it goes on about doing the pinch test etc to get the settings right but thats
on a plane and I can't run the heli at full throttle and pinch the fuel tube
for obviouse reasons,
I know its an old engine but also know it has'nt had alot of flying time and
I don't think it needs a new engine, just the right setup, and a bit of TLC and I'm sure it will be fine.

I've e-mailed the ST web site,,, but no help!!

so if anybody has used or has an ST 61,,
any advice or tips would be Appreciated
Thanks

[Ade_Law]

can you be a little more precise about the idle problem? does it tend to slow down and stop? If so its a bit rich on the low end.

however... be careful. it might be rich for a good reason. it is common on engines for the midrange to be too lean. this is accounted for by richening the bottom end at the expense of a reliable idle.

After leaning the bottom end needle hover the heli for 1min then check the backplate temperature. if you cant hold your finger on the back plate for 10secs its too lean.

Ade

[Tripler]

Hi Ade
on idle, its what I call hunts, idle's for a bit, then rise's and then drops back,
at half throttle it runs very rich,,

[Janek]

Your "grabby" clutch might be stopping the engine from idling properly, might be time to sort that little problem out ?

[Ade_Law]

that could be muffler/fuel/glow plug related

STs arent well known in helis in recent years anyway so its hard to say without getting my hands on it.

grabbing clutch could be down to the idle being high (to make it reliable) or down to the clutch being knackered.

[Tripler]

Hi Janek

The clutch has'nt been a problem in the past when the idle was ok, I ment by
grabby,, that the on off point is quite small as I think its a heavy duty some sort of plastic lined clutch, and the person I got it of said the clutch was grabby
and might need o.5mm or so taken of the lineing, or wearing in a bit.

[Tripler]

Well chaps, I appreciate your help,, and understand alot of the probs I have
are down to inexperience on my part, but I now know what to check and aim
for, its a matter of tinkering to get it right, "which I enjoy doing"

Thanks

[Janek]

The pinch test being referred to is an idle pinch test, I'll try to explain, but I might get the detail slightly wrong as I don't use it myself, Ade'll probably jump in and correct me :-)

Get the engine started, and leave it to warm up for a little while, you might need to leave the glow driver on to do this initially.

Once it's warm, pinch the fuel hose, as near as possible to the carb, now watch what the engine does before it shuts down (which it should !), if the engine speeds up before it dies, it's too rich, it it runs on, and on before it finally dies, it's too lean. If the engine runs for a little while, then dies quietly, it's OK. This tests the low end, but is not particularly accurate, but will get you in the ball park.

Did I get it right ?

Ade, did I get it right ?

[Tripler]

"Come on Ade answer him"

[Tripler]

I did read that in the ST manual, but it seemed to contradict its self a bit,,
or perhaps it was me?

[Ade_Law]

pinch test is ok. however your best listening to the engine at idle. if it slows down coughs and dies at a reasonable idle speed then its too rich. Pinching the fuel line will keep it running in this instance. If its lean it will sound tinny and cackle on idle.

but as i said, be careful because leaning the idle will lean the midrange which check the temperature of the back plate after a 30second hover.

Ade

[Tripler]

Thanks Ade

[Raptorite]

There is one other thing that might be worth a look, make sure the exhaust is sealed properly where it mates with the port on the engine, as if this is weeping slightly, it will affect the way the engine idles. It will need to be overly rich to compensate for the loss from the leak which will therefore affect the mid range.

Cheers,
Pete.

[Tripler]

I will check that,, Plus there is a silicon tube connecting the
exhaust manifold pipe to the exhaust pipe, held on with cable ties,

Thanks
Tripler