rough mid-range and carb questions

"..........roughness mainly from about 2300-3800 rpm"

Rutsy,

It must be annoying to have this persist ant symptom BUT the RPM range you have quoted is not really an operational setting (beyond starting, warm up & slow taxi).

The Rotax ignition system is fixed & optimal around the 5200 RPM (range 4500-5500). Outside this, particularly at low engine speed, the pilot can expect sub optimal fuel burn & rougher running.

Is it possible that you have become sensitised to the less than silky smooth operations below flight RPM's ?

The main time I'd see those RPMs is on base or final, and it's not anything you'd be able to ignore.  For now, it's a mystery.  

As for those epoxy floats, if I decide I should replace the floats, those are going to be my choice.  I definitely appreciate the comments on those.  I've been sifting through all the service bulletins on floats, and it's hard to say what I should have.  

Truth be told, I hate carbs, and the only thing worse than a carb is two carbs :-)  

Rusty  

When carbs are properly cared for they run just fine and require very little maint. beyond a carb sync. That takes me about 5-15 minutes to do.

Rough running can be caused in your rpm range by several things.

i.e..... carbs not synced PROPERLY, dirty carbs. old poorly kept carbs,  Improper setups within the carb usually from the owner, gearbox improperly shimmed or worn out, prop not balanced and it may not even be the engine. I've had several where owners swore it was the engine and it was wheel pant vibration, tires spinning and not balanced, other items on the plane shaking at certain pitch and speeds.

Carbs aren't always the culprit.

Russell, I had a vibration a year ago, base to final. Lockwood Aviation replaced the gear set and the clutch dog. The dogs had a flat spot on them. That was the cause and replacement of these parts resolved the vibration problem. $2000 parts and labor and I removed and replaced the gearbox.

Garrett,  My old gear box doesn't have the clutch.  60 hrs ago it was fully serviced by LEAF as I mentioned in the initial post.  I haven't done anything to make life hard for the gear box in the past 60 hrs, so I'd really hope the gear box isn't the problem. 

I'm really starting to think having full ignition advance in the lower RPMs may be part of the issue as Sean mentioned. As I understand it, a richer mixture makes ignition work faster, so an over rich mixture could compensate for the additional advance.  If we're stuck with the full advance, then maybe I'm not over rich enough.  It runs fine at idle 5000+ RPM, just not really in between.  It's NOT a subtle roughness, so I'll have to resolve it one way or another.  

Thanks,

Rusty