Zenoah 260 idling problem

[Muddy]

Hi All,

Been a while since I visited here.
I have a mate's boat in my garage today, he says it hasn't been run for a year. I don't think he drained the fuel (bad man!)
It is a fibreglass Enforcer hull with a Zenoah (260 I think - not too sure, as I prefer nitros)
I noticed the choke was still on by a small amount, and since I have made a new choke lever from an old servo horn (now I can turn the damn thing on and off)
I fired it up, tuned the high needle like a chainsaw (lean - peak revs, then richened off a bit to drop the peak revs down a bit) about 1.5 - 1.75 turns out.
Carb is a Walbro.
I now have the idle speed up a bit, just to see where the low needle is best.
It seems good at 1 - 1.5 turns out.
However, after doing this, and settling the idle speed back down, the engine will run very well on a burst of power, but allowing it to come down to idle it revs lower than how I've set it.
Have I just made high end a little too rich?
or is the carb needing disassembly?
It's as though it floods a little when the butterfly drops to idle/closed (open by 1 or 2 mm still.)

fuel is new, plug is a good browny grey. Spark is fat.
I know it's a fuel issue, but I'm running out of ideas.

Anyone???

[RickE]

The fuel left inside the tank and carb for a year might have created a "varnishing" problem inside the Walbro carb body. Cleaning the carb might cure your problem plus I'd check the inside of the tank for any signs of residue from the old oil/gas mixture.

RickE

[Muddy]

Got it sorted.....took of the card, cleaned the needle + seat, solvent cleaned the rest, flattened and sealed the insulator block, and my dumb thing was too low an idle speed....I'm more used to tuning cars, and low idle is OK

different rules for boats, so I found out!!
She's a screamer now, and my buddy is smiling again!