McCulloch PM 484 YUKON 40

[Memmeddu]

Hi everyone hope you all doing well and having a nice Christmas .
So I've decided to save a chainsaw I was thinking to throw away , just because I've found particular serial numbers
000000094 on the carters and 2 on the cylinder .
So I believe is one the first 100 saws of that particular model from McCulloch
40cc
Practically wide open muffler (from the factory)
Manual oiler
Great compression ,it has a Stihl pull rope.
So the problem is that is hard to start and adjust the carb.
Because of it's great compression and lack of fuel .
Very impractical to use because its chain lubrication system (manual pump) but after 100 pulls it starts and runs not so bad .
So
I know diaphragms are good.
I know gaskets are good.
I know top end is good.
Just wondering about what's wrong with it
I don't know if it's the carburettor,the fuel lines ,the filters or the air inlet valve for the tank .
Fuel mix is fresh , used 2.5% synthetic oil

 

[MCKDAVID]

Plug out, and a few drops of mix down the bore, try it, if it starts fairly quickly, you know it's fuel related. Or at least you know the ignition is fine.

Given the age, I'd also be checking crank seals for leaks.

 

[Memmeddu]

Found a weird malfunction .
Crank seals can't be replaced or at least I can't , but they seems good.
So the carb gives way too much fuel , and blows even out the carb .
So I believe that it needs adjustments .
I think that it's one of those saws which are meant to have
¾ turns low jet
1¼ turns high jet
Maybe tomorrow morning I could try to adjust the carb .

 

[Memmeddu]

So I've been trying everything .
I've checked the reed valve and it was open 2+mm gap
I've adjusted it to stay roughly 0.5mm
Solved so the issue with fuel being sprayed in both directions (into the intake and towards the air filter)
Changed the air filter .
And I can't adjust the carb .
This saw doesn't fourstroke .
It's always lean but if I give more fuel it will fload and die.
So I'm pretty sure that it's a carb issue or an high RPMs engine .
So I've decided to adjust the carb to be easy to start , and use the spark plug as reference