Hi Dave,

I've about 4 gallons Wildcat 20/20 through my 110. I have set the valves to .003". Running ok, but I seem to need a very lean regulator setting to get the engine to come off idle good. I've had to slowly turn the regulator in from flush as the motor broke in. The regulator needs to be 3/4 to 1 turn open (from full in)in order to transition good, and thats a long way in from flush. If I open it up more, it just bogs(smokes) and very slowly transitions. Also, the engine does not want to hold a steady high rpm. It winds up to 9300rpm with a APC 16-6, but then falls back to around 9000. High speed needle needs to be around 1 turn open to get max power. Idles great, and generaly runs like it should other than this. I looked at the diaphram, and it has a dished out appearance in the center. Anything unusual going on here? Thanks for any insight.

Kevin

Nothing really unusual. Try changing to some Cool Power 30% heli fuel and see what happens.
If all the adjustments richen up from where they are, you'll know right away that it was fuel related.

Dave,

Thanks for your suggestion, I'll try some CP 30 if I can find it. As an experiement I cut a new diaphram out of some mylar drafting paper and reset the regulator to flush. The thing took right off, and transitioned very crisp. By about 3 tanks later, I was back to slowly closing the regulator. I found it very interesting how sensitive the transiton is to the diaphrams condition. Wondering if it needs to be a bit stiffer material?

Kevin

Try doubling the stock diaphragm, might help.

After some more analyzing I noticed my plunger was flush with the regulator face. In other words, the plunger seat(little silicon thing) could barely seal at the bottom because the top of the plunger was up against the diaphragm. I trimmed the plunger stem off a teeny bit, and now my motor runs with the regulator setting back in the flush zone. Still need to get some 30 nitro and try that. I'm still a bit plagued by the motor getting a bit flat(in the air) in the upper midrange if I set the regulator to come off idle good. If I set it for a nice rich fat sound in the air, then it will load up after a long landing approach and idling on the ground a while. Maybe this is normal? Otherwise it will idle all day on the ground, just does'nt want to come off idle after landing.

I ordered a couple sets of plungers and diaphragms today. Will try one of those and see if its any different.

Kevin

Let us know, thanks.

Hi Dave,

Got my spare parts today. YS service sent me #YS0176 regulator plungers. Says for 120, 91, 140. This has a lot smaller top plunger area than what originally came with my motor. I presume they know what their doing and this is OK for the 110, maybe it will work better? We'll find out later.

Kevin

That's the one we use for replacement. It does work better.

Got to test out the new plunger this weekend. The smaller one does seem to work better. Throttle response is a lot quicker, and it does not seem to load up with extended idling. Main needle is now open to 1 1/2 turn. All seems well

One more question. I have what seems like excessive oil residue on the firewall and inside the cowl(above the exhaust line). It gets all over the muffler and burns on. Is it possible this oil is coming out the carb, or is it more likely leaking out the seam on the muffler? I do have Teflon tape on the header and muffler threads, so those joints are not the leak source. Just wondering if its normal for these to be so messy, although with 20% oil it does not surprise me.

Kevin

YS engines run pretty wet. What you are seing is not really unusual, but part of it may be from the muff and part from the carb.

Dave,

Thanks for all your help.

Kevin

Good Flying!