# Stihl MS290 - Need full choke to run



## quid_non (Nov 13, 2007)

Hi all!
Got an ~5yr old Stihl MS290 saw with a Walbro HD-21B carb. Saw ran fine for several years (not too many hours) until....
Now it requires full choke to even consider starting. It will start (w/ Choke) but immediately bogs out when the throttle is applied. If you release the choke after starting, it dies.

Electronic Ignition, New plug, good compression (~150psi - steady), good spark (checked with tester). I cleaned the fuel line (no blockages), new air filter. I removed the carb, dismantled and soaked in cleaner, then re-assembled with the original gaskets (they all looked fine). All this made no difference. 

Other threads may suggest an air leak - I can't keep it running long enough to spray carb cleaner on to test and don't have a tester. Any suggestions to trouble shoot?

Thanks!
Wayne


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## hankster (Jan 1, 1998)

If you put some fuel mix straight into the carb will it run longer?


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