MS290 Walbro carb confusion

[katarn444]

Hi All,
I am in the process of installing a Hyway MS390 bigbore kit on a free low hour MS290. I am halfway through but struggling with decisions around the carb. At bare minimum I want to rebuild the stock one but can't figure out the model. On the left side of the adjustment screws it has a big "HD" then under it has a little "18C" then under a big "L" then under a little "141". On the right side of the adjustment screws it has a little "140" and under a big "H". Lastly on the pump cover it has "21-477 T8-7"
First question is can anyone help identify this as I have not been able to. I find rebuild kits that look right but do not have these model numbers.
Second question is it worth rebuilding or should I just get a different carb that may work better with the bigger displacement engine? If so what.

Thanks for your thoughts

 

[Aknutter]

Hd-18c
You'll need to remove the limiters.

 

[cscltd]

i think the kit you need is
k10-hd

 

[katarn444]

Hd-18c
You'll need to remove the limiters.

Thanks I think you are right. Yes indeed on the limiters.

 

[stihltech]

Pull the limiters, cut off the limiter tabs and reinstall. Makes it easier to use a small screwdriver to adjust full range.

 

[katarn444]

Pull the limiters, cut off the limiter tabs and reinstall. Makes it easier to use a small screwdriver to adjust full range.

I wanted to confirm that the saw is running. That was the correct carb rebuild kit.
One last question, the reason for the rebuilt was a scored cylinder and piston on the exhaust side. I assume it was running lean. I changed the impulse line even though I saw no evidence of a leak. The only problem I found was a bit of sawdust in the carb a screen. Clearly this could have been starving the engine of fuel. What can I do to prevent this in the future besides normal maintenance. What are the symptoms of an engine running lean so I know what to look for? I want this saw to last as I put a lot of time and money into it.
Thanks

 

[cscltd]

install oem fuel line and oem orange stihl fuel filter will help with the fines and fuel lines cracking are a bit of issue on the early version of fuel lines