I began the run in process of my 353 today... 3 good tanks on the bench.

I opened the top 1 turn, richened the bottom a 1/2 turn and to get it up to a fast idle it took most of the idle screw to keep the revs and temp up.

From this short experience I can assume that the bottom is rich by default, I had good temps at around 5000 rpm and a steady rich fuel mixture flowing out of the pipe... yes my eyes were burning.

I expect my next step on track will require a considerable leaning of the bottom in order to get my idle gap to where it should be. Will keep you informed.

Fuel was Platinum AT Racing.

I did, went to a P3 plug.

NO NO NO NO NO. Ditch that plug. Nova 6 or 7 or Sirio 6 or 7. NEVER EVER EVER run OS plugs (especially a P3, WAY too hot) in a Nova motor.

i ran os plugs in my nova before engine still good, years later with os plugs

So have I. Yes it works, but it's far from ideal. Also leak problem are common (though not universal) with OS plugs in Novas.

Don't do it. Novarossi engine should use novarossi plugs. Vice versa with OS engines. The button head and plugs made from novarossi and OS, they have different tapered ( different angle ).

P3 plugs are meant for off road. Thin wire element( hot ) ideal for short burst of high rpm. ex. Jumping.

P7, P8 plugs are meant for on road. Thicker wire ( cold ) ideal for long period of high rm. ex. long straight

How about thin air? We typically see 7000+ DA, thinner air=less power. I run Byrons 30%.

I run the Nova C5TGF plug exclusively in all my nova based .12 engines.

The C5TGF it the plug that comes in the 353 race engine

thin air you just need leaner hsn,it's not related to the plug.especially you'r using 30%,should go for cooler plug and add 0.2mm of shim

He is at 5280 feet elevation. I don't see how adding .2 of shim would help. I understand that 30% nitro needs more room, but at that elevation you could add .1 or leave it alone.

After reading more about this it seems like this is a case where the low end is supper rich and the idle is set too high and that is why the idle hangs so badly. The supper rich low end setting gives you a false idle. So when you clear it out the idle hangs because of how high the idle is set then drops down at some point because of the rich low end.

http://www.teampicco.com/index.php?o...=66&Itemid=513

I think that might have been the deal, I will get some plugs and see how it goes next track outing, thanks for the help everyone and Mike. Much appreciated.