Stihl 090 carb. question

[Robert]

I was trying out my newly acquired 090 this past weekend and I noticed right off the bat that it would not come up to full throttle, like it was running really rich. I let it warm up and started to adjust the carburetor. When adjusting the high end, I turned the screw until it lightly bottomed out and then backed off one full turn. I don't have a tach. so I have to do everything by ear. As I turned the screw in the rpms began to come up. I turned in until what I thought was full speed and then backed off untill it just started to gurgle. At this point the needle was only 1/4 turn out from bottom. Is this a worn out seat or can something else cause this to happen? The 090 carb. is a little different from my other saws because of the governor. Are the adjustment procedures different? What else should I check? It idles fine and accellerates fine but it is hard to start. I don't have to use the throttle lock on a hot restart on other saws but it seemed to help in this case. I'm sure the carb. could use a good cleaning and a kit but if the high end seat is worn doesn't that mean a new carb.? BTW, a cold compression check showed 150psi.

Thanks,
Robert

 

[gatkeper1]

I have a manual, someday I will be able to afford an 090.
Until that time I will just read
The service manual states the governor must be defeated to adjust max RPM.Defeat the gov by using a screwdriver to hold the gov in its idle position,Set max rpm to 11000. release the gov and run the moptor to full throttle. it should be held to 8000rpm by the gov. I guess a tach is the only way to do this properly

 

[Dennis]

Robert....was that the "competition 090"?? Just curious how much it went for if you dont mind my asking...

the govenor can also be defeated by removing it (the linkage) completely I believe...if you need any 090 parts let me know...John and I have lots of them...parts only though...no complete saws guys...

 

[kdhotsaw2]

090 STIHL Carb

Hello robert,
All the 090's we modify the first thing we do is remove the link between governor and the choke mechanism. some saws only turn up to 7500 with it hooked up . also impossible to adjust as the carb goes rich when it gets to that rpm. should have never been installed on that saw.
ken

 

[Robert]

was that the "competition 090"??

No, it's one I got from saw-king a couple of weeks ago. Seems to be in good shape except for the carb. thing. The linkage shouldn't be a problem, it kept vibrating apart anyway. When I was trying to adjust the carb the first time I didn't even think about the governor closing the choke. That might be the problem so I'll take the linkage off and try it again. I was just reading the service manual that came today so I still have a question about adjustment. This time should I adjust as I normally would (turn in to max rpm then back off untill it starts to 4-cycle)? Sounds like if I did that I would I would be operating the saw way above recommended rpm. The manual says adjust the high speed side to 11,000 rpm and let the governor regulate it to 8,000. If it makes any difference, this is going to be primarily a milling saw.

I'm thinking about getting a tach anyway to double check myself. Has anyone used the wireless analog model like the one from Mfg. Supply? It's much cheaper than the smaller digital models I've seen (and this isn't my profession, just a hobby - a sick, twisted, addictive hobby).

 

[sawracr]

Robert, the 090 was equipted with a wind-vane govenor that attaches to the choke butterfly of the carburator, a great idea to keep the saw from going to lean, but not of much use in the Hot Rod world of chain saws. If this saw is going to be used for wood cuting or milling leave it on, but I know everyone reading this post is thinking.......... TAKE IT OFF DUDE!. Good for you the 090 is a big powerhouse have fun. Jon
P.S. I've got one I call Mac Attack, cause it gives the 101 Kart motor saw a bad time.
P.P.S Darin one liners are funny, you POOP HEAD.