OS 1.60 & Perry VP-30 question

[maineflyer]

Guys,
I have a 1.60 and perry VP-30 on it. The motor has about 7-9 tanks through it. I have the idle dialed in fairly well and the high end is taching a APC 18-6W at 9,000 with great smoke and am idling at 2,300-2,400. I could probably get a little more from the high end but am not pushing for a lean run. I have an OS A-5 plug and am running 10% fuel. The problem I am having is an inconsistant mid-range. I can idle on the bench for a minute and get instant transition to full throttle but in the air there is sometimes a warble in mid-range and I am seeing some lag in transition it seems. I am wondering if I am a tad to lean on the low end as I have had a dead stick with it and the lagging during a quick transition. I don't dare get too low with the Yak it is on as I don't want a 20' dead stick.

Any thoughts on how to dial this in would be appreciated.

Thanks
Jeff

[hornet dave]

Mine was doing the same as yours. On the ground, the transition was fine, but in the air, it burbled a bit in the midrange. You need to lean up the idle mixture some more, do it about 1/16 of a turn at a time, and every time you lean the idle mixture, you need to richen up the main needle about 3 clicks or else the high end will lean up on you. I figured this out yesterday after toasting an A5 plug, but I've got most of that mid range burble fixed. One more day at the field and it should be perfect.

[maineflyer]

I will try it. One guy suggested leaning out the midrange by turning the pump pressure down and adjusting the high and low needles but I don't see that helping. What do you think?
Thanks
Jeff

[hornet dave]

You know, I don't really have an answer. I have my pump set at about 2 turns out from the stock position, and I think my main needle is about 1 3/4 turns out right now. I would think that if the main needle gets to the point where it's less than a turn out, then reducing the pump output would probably be a good idea. But with the main needle at the 1 1/2 - 2 turn range, there seems to be enough adjustment available for the idle mixture to make the engine run well.

My pump is hidden underneath my cowl, so I personally would take the lazy path and try to get it to work without adjusting the pump. But if worse comes to worse, you always have the option of adjusting it.

[proptop]

If it's loading up a bit in the mid-range, try backing the pump adjusting screw out some...a quarter of a turn to start with.
If your high speed needle is less than a turn open, and it's sensitive in adjustment, that's also a sign that you have too much pump pressure.

[GonePostal]

I had a160 with pump on a 72''KATANA. I now have the 160 on an EF yak54 74" with no pump and have had no fuel flow problems . and now minor adjustments for the temp.only. my 2 cents THANK YOU

[maineflyer]

I am going to back the pressure down some I think and see if that smooths the mid range out. It is very minor but I just want to try to get it very smooth.
Jeff