In many of the threads on problems with SuperTigre engines, you'll see the same complaint pattern appear on SOME of the engines.

Namely, you can get a GREAT transition and high end, but idle bogs down... or you can get a GREAT idle and high end, but a lousy transition.

Supertigre suggests angling the "cats eye" venturi to help eliminate this problem, but that is a workaround not a real fix.

I have various SuperTigres and I find that they are most reliable and powerful when I forgo adjusting for a good reliable low idle.

I believe the problem is with the design of the throttle barrel.

There seems to be a large amount of air that makes it's way around the barrel where it is inserted into the carb letting the engine continue to run with the rich fuel mixture.

SuperTigre provides a rubber seal that covers this area, but I believe it is ineffective.

Normally my flights consist of:

- Start up engine and let it warm up at mid throttle
- Drop it to high idle and get plane out on runway ready for takeoff, at high ( rolling ) idle.
- Gun the engine quickly once or twice to clear excess fuel
- Takeoff
.
.
- On landing taxi in, kill throttle and set barrel fully closed.
- WAIT 30 seconds or more ( as the engine will continue to run fully closed! )
- Pinch off the fuel line and wait another 20 seconds for the engine to finally shut off!

I get NO deadsticks, but if I cure the overly rich idle condition, the transitions may kill the engine.

If it was not for this problem, which has been somewhat consistent accross engines, the SuperTigres would be a bargain and reliable.

Note:

In Sport Flyer magazine Oct 2007 I ran accross an article where the author was having a similiar issue with an Avistar .46 engine.

Try as he might, he could not cure the same problem.

Eventually he resorted to filing a small 2mm "half moon" on the throttle barrel opening at the point of smallest closure.

This increases the airflow at idle permitting a leaner low speed idle mixture.

I had an extra ST carb laying around, purchased in my attempts to cure the problems... so I tried the same thing with the ST carb.

Sure enough it fixed the problem PERFECTLY.

I've done this to two similiarly affected engines with equal success each time.