Larger or smaller

[Norfolk]

Hi Guys,
I currently have a Muggy 186 with a PHBH 26 carb with the following carb set up:-
Main 104
Pilot 48
Atomiser AV266
Needle X7, second clip
Slide 40
Choke 70
Varitronic ignition set at 19 deg

The engine idles best when the mixture screw is fully screwed in and previous threads indicate "Closed to 1/8 throttle - air screw and pilot/slow jet", question is do I need a larger or smaller pilot jet or am I barking up the wrong tree, also....
Reving the engine up to approx 3500 rpm, the engine then gives a very distinct jolt and from on then reves very smoothly.

Any thoughts please, thanks

Norfolk

[CHRIS in MARGATE]

When you try to rev from idle to 3500 rpm does it sound breathless or does it gurgle and 4 stroke?
If it's breathless you need a larger pilot. If it's lumpy and 4 strokes you need a smaller pilot.

But .... you must get it right and keep checking plug colour.

[Rich Oswald]

I wouldn't recommend running with mixture screw full in. You are obviously too rich on the pilot and trying to weaken it so you need a smaller pilot jet. (I think that's the right way round).

Rich'

[coaster]

I'm not an expert on the Varitronic but 19 degrees static sounds a bit too retarded for a variable ignition, thought maybe 22 or 23 would be nearer the mark

[Norfolk]

Hi guys,

Many thanks for your thoughts, it has given me something to work on.
Regarding Coaster's comment of ignition timing, it is set at 19 deg with a strobe light and the engine running at a fast idle, from other threads of engines overheating and seizing, I thought this was best or am I becoming paranoid.

Norfolk.

[dickie]

Hi guys,

Many thanks for your thoughts, it has given me something to work on.
Regarding Coaster's comment of ignition timing, it is set at 19 deg with a strobe light and the engine running at a fast idle, from other threads of engines overheating and seizing, I thought this was best or am I becoming paranoid.

Norfolk.

Coaster is right with 19 at fast tickover it will retard to 11 at 6000 rpm; way too much.

23 could be too advanced if you spend all your time at low rpm, in which case you don't really need variable ignition.

[skinnerwill]

as above ,sounds like pilot needs changing, mixture screw shouldn't be screwed right in, and yes do plug chops