Another Stihl FS94R issue

[Mark956]

I have two FS94Rs, 2yo and 3yo, both have been great. Left gas in the 2yo last season and wouldn't start this spring. Got a Stihl rebuild kit ($20), it now runs but stumbles and dies after holding the throttle at any speed consistently on the throttle dial. With the throttle dial wide open, if I hold the trigger at about half open, it will run longer but the bottom line is again the same. It will not run at full open, just stumbles and quickly dies. I can let off the throttle before dying, and repeat the process, though for a shorter duration. It will run at lower constant speed with the choke pressed in, and no throttle. Ran through all the possibilities - plug, muffler, air filter, fuel filter, idle speed, high speed adjustment - with no improvement. Bought a new Zama on ebay ($22), installed it and it doesn't seem to want to prime. Primer bulb is good with visible gas. It will run a few seconds with a shot of gas manually into the carb. Put the original back on and the same situation persists. Gas is flowing out the tank to the carb like a river when the hose is disconnected. Ebay seller has offered to reimburse for the carb, but can give no advice. I've reviewed the FS94 workshop manual, no further insights there. At this point, planning to call the Stihl help line tomorrow, and possibly try another new carb.

 

[DND 9000]

Do you have access to an ultrasonic cleaner? Try to clean the carburetor with that or go to a properly equiped workshop with an heated ulrasonic cleaner. Maybe this will fix it. In my opinion something in the carburetor is clogged and the machine doesn`t get enough fuel. Don`t let it run like this or it may blow up.

 

[Mark956]

I found a small engine sales and service shop, and took the carb in. The counter guy said it would probably best if I just purchased a true OEM replacement, as they find their heated ultrasonic cleaner is successful only about 50% of the time when trying to resolve carb problems. The cost would be $25-30 to do the cleaning, and Bailey's has replacements at $60. So I am now trying just a bath in straight Sea Foam, and plan to take it to the certified mechanic at the local Stihl store to tune the carb once I get it back on. I said before I adjusted the high speed setting but today realized my socket wasn't reaching all the way down the adjustment hole to reach the adjustment hex screw. So I am hoping in fact it still might be a high speed adjustment issue.

 

[Mark956]

Just to close out the thread, I ordered a new carb from the local Stihl dealer. Installed it yesterday and it is running like new.

 

[DND 9000]

Thanks for telling us the solution of that problem. It`s always good to hear what cleared the problem.