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pilot jet size

Posted: Tue Aug 18, 2015 8:35 pm
by idc23
My engine is running quite well, only prob is when slowing down from fast run the revs don't come down clean sort of holds up slightly then comes down, feels like it may be weak, would the pilot give this problem. It is a latest muggy 186, 28 mm delly.55 pilot.

Cheers Ian

Re: pilot jet size

Posted: Tue Aug 18, 2015 10:15 pm
by rainbowrunner
try lifting the needle one notch, i had same problem with a 25mm, all ok now, you can always put it back if it does,nt help

Re: pilot jet size

Posted: Wed Aug 19, 2015 8:11 am
by Chris in Margate
If all else ok then slightly bigger pilot.
But elsewhere you are posting that you are having trouble starting.

Re: pilot jet size

Posted: Wed Aug 19, 2015 8:45 am
by idc23
Will try a bigger pilot, the starting is better no throttle ;)

Re: pilot jet size

Posted: Wed Aug 19, 2015 12:15 pm
by coaster
idc23 wrote:Will try a bigger pilot, the starting is better no throttle ;)
8-)

Result 8-)

Re: pilot jet size

Posted: Fri Aug 21, 2015 2:18 pm
by olliewtf
I had a similar ish problem. I just couldn't get my mid range rich enough it was either too lean or too rich at the change of a needle clip or in fact a needle. I am also running advanced then retarded ignition which needs richer jetting up to midrange. After thinking it was a needle problem as I had an av266 already and it's only a small block, I thought about it a bit more.
The atomizer controls the full amount of fuel available and the needle only meters it.
Therefore I went up to av268 and from x13 back to x7. Problem solved.
Upping the pilot is a good shout but I would spend alot of attention on midrange jetting. I found the best set up was great for going through the gears but if I really put it under load it would drastically lean out.

So. What's your full set up and what's your current jetting?

Re: pilot jet size

Posted: Fri Aug 21, 2015 3:39 pm
by idc23
Thanks for reply, muggy 186 latest
28mm phbh ram filter
115 main
40 slide
Air screw 2 turns
55 pilot ? might change
x 13 2nd down
Timing 18
264 atomizer
Bgm stator
mid weight flywheel.

Re: pilot jet size

Posted: Fri Aug 21, 2015 6:21 pm
by olliewtf
I would get out on a fast road in 4th and hold it in the mid range. Do a plug chop. I would try av266 and x7 2nd clip. If that's too rich then av264 and x13 is fine as long as the plug also says so!