Dave,

I have followed your many posts on getting the YS 45 dialed in. All I can say is WOW! I richened it up just a little because I am afraid I am going to blow it up. This thing is running like a bat. (No, I am not complaining [sm=biggrin.gif] )

But seriously, I really inspected this engine before mounting it to my ultrastick to make sure that things like the rear bearing were ok, and the pump was in good order (I got this used from a guy who didn't know how to tune it).

What is the realistic SAFE RPM range for this engine. I am running the APC 12.25 X 3.75 on it as you mentioned in an earlier post. Going up, it is phenomenal compared to the Webra I had before. On a short field take off, I actually accelerate in the vertical. But I am petrified of downhill run with anything more than about 1/3 throttle because it is spinning up so fast. One other thing that an old timer told me not to worry about, there appears to be fuel lightly spraying from the front bearing while static testing at higher RPMs. It that OK?

FWIW 15% cool power Synthetic, OS #8, One head shim. Needle set to throw a healthy smoke trail when motoring around the sky, and a rich enough at idle to load up if setting on the stand too long.

Bob

P.S. I am in the process of rebuilding the one that shredded the bearing for my New KAOS.

The only real limiter is the rear bearing with standard size props. The engine is good to 19000 plus in all other respects and you'll never get it that fast even in a dive with a 12.75" prop. Get a good plastic retainer rear bearing for it at www.pspec.com It uses a 15mm bearing like so many other engines in this size category.. Just remember that crimped or riveted cage bearings aren't really much good above 15 or 16000 rpm. They tend to come apart with disastrous consequences for the upper end.

Bob:

I have been asking about a 45 problem I am having, but have not found a solution except running my 45 on 30% cool power. As I had said in a previous post, it leans out in the air after the first 5 minutes, I land and richen it up a bit and then it is good for another minute or so. This is on 15% cool power. I too have this in an ultra stick. You mentioned you have one head shim, is this the one which comes stock with the engine?

If this reply is improper to the list could you email me privately. My email is [email protected]

Thanks

Joel

Up

Sorry for the late reply. I have only one shim. I believe it came with the engine. I have refrained from using higher fuel because I don't want to wear my engine out. One thing I have learned. I let the engine warm for about 5 minutes when starting cold. Dave is probably more qualified to answer this, but I would look at a few different things. before I start, I would like to note that I have the stock fuel tank and hoses from Hanger 9. The easiest thing to start with is this tank. Make sure that the fuel is flowing correctly, and the one way valve and fuel filter are working properly. If all is well, I would richen the pump. Perhaps the pump is leaned to a point that it is unable to keep up in the air. Since setting mine up, I have run in temps from 40F to 85F without touching any adjustments. I run Cool Power Synth 15%. If all of the above is fine, check out the pump gaskets to make sure the holes aren't obstructed, and the parts of the pump are in good working order.

Bob

Edited to remove non YS rep. response.