ORIGINAL: kingaltair

Some comments on the Taurus-2 and the SuperTigre .56 engine:

It has been a real experience "working with" the ST engine. The engine can run very strong, but the idle has been unpredictable. The needle valve is loose so the engine tends to "adjust itself" while running because of vibration. Under those circumstances, it's hard to get the carb set correctly, and that also affects the engine idle. We placed a piece of fuel tubing over the needle valve which helps some, but the needle was still able to move on its own. Just this past weekend while testing mufflers, (another story in itself), a suggestion was made to put a second piece of wider lumen tubing over the first. This DOES keep it in place, (mostly).

The carburator on the ST is"interesting". I was told by one source that during the 60s, ST was putting out a different carb every six months and I believe it, (BTWsome literature in my box has a date of 1970, so I'd have figured ST would have got it perfected by then, but no..no quite). I now have 4 ST .56 engines, and three of them have different carbs, (with the throttle adjustment on different sides). So far I haven't switched out carbs....I've been advised to go a different route, (see below). The needle valves are not interchangable.

John Castronover and I drilled out the idle air mixture hole a bit. This helped the idle some by allowing more air, but it could probably use a bit larger hole as I was able to totally unscrew the idle adjustment screw without it making much difference at the end of its travel. In the end, the idle wasn't bad...it was passable, but I'd like to get better.

The engine overall is still running rich, (with appreciable oil residue and some light smoke),with about 1-1/2 hours of time on it. If it is leaned out, it dies out. I would think I should be able to get more than 10,500 RMP with an 11X6 wood prop, but that's the best I've been able to get so far.

One thing that it appears ST DID keep the same is the throat size where the carb fits into the engine. I have been told by a VR/CS buddy with a number of ST engines that a MODERN carb from its 40-51 size engines will still fit perfectly. I understand their modern engine carbs are much better. With that in mind, I have a new carb on order, and hope to slip it on the engine with the hope of much improved performance.

I've also been given some advice on fuel. I now use 5% nitro Omega fuel, (the lowest nitro available at the local hobby shop). To that I've been told to add three ounces of castor oil to keep the oil content above 20%. I haven't done that yet. I'll keep you informed. I took pictures of the engines I have...see attached
Duane