Retuning the Carb

[abbowhunter]

First post here. Seems like alot of good knowledge on here. I have a ms290 and a ms361 and a buddy borrowed both and figured he would make his attempt at making them run better and "adjusted" the carbs on both. Now that I have them back, neither run like they used to. The 290 runs for a bit then dies and seems really hot and the 361 starts but as soon as I hit the throttle, it instantly dies. How do I re adjust both to get them running properly again? Thanks for any help!

 

[Joe Kidd]

First post here. Seems like alot of good knowledge on here. I have a ms290 and a ms361 and a buddy borrowed both and figured he would make his attempt at making them run better and "adjusted" the carbs on both. Now that I have them back, neither run like they used to. The 290 runs for a bit then dies and seems really hot and the 361 starts but as soon as I hit the throttle, it instantly dies. How do I re adjust both to get them running properly again? Thanks for any help!

Lots of good info here

Carb Adjustment on Pro Chainsaws Info

 

[KenJax Tree]

I would seat the screws and open them 1 turn so it starts and go from there.

 

[Joe Kidd]

I would seat the screws and open them 1 turn so it starts and go from there.

Abbowhunter, Gently seat the screws.

 

[abbowhunter]

Okay thanks. When will I know where to stop turning the screws back out? Is there a certain amount that they should be backed out?

 

[kodiakyardboy]

Okay thanks. When will I know where to stop turning the screws back out? Is there a certain amount that they should be backed out?

Just one full turn out from bottomed out. That usually will make them close enough to tune.
You will have way more ajustment than you need before the screws actually come out.

 

[sbhooper]

You have just learned the first rule of chainsaw maintenance. DON'T LOAN THEM TO ANYBODY!:bang:

 

[nstueve]

You have just learned the first rule of chainsaw maintenance. DON'T LOAN THEM TO ANYBODY!:bang:

No the first rule of chainsaw loaning is to have a cheapo wild thing from wal-mart and if you're buddy can prove to you he can take care of that saw you can upgrade him over time! LOL! I still don't have a friend good enough to barrow my 9010! LOL....


BEEP BEEP BEEP... back this truck up!You all forgot something about carb tuning!

If you have limiter caps on you won't be able to to turn the screws out 1 full turn! duh! :bang:
There are small red caps on the carb adjustment screws (at least on the 290)... You need to use a drywall screw to remove those red caps and THROW THEM AWAY!!!

After removing the limiter caps you'll see the plain slotted screws in the carb and you can then turn them all the way in (clockwise) then turn them out about 1.1-1.2 full turns. this will richen up your top and bottom end and eliminate the lean conditon that causes those ms290's to burn up pistons! then do a muffler mod!

Someone else needs to comment on the 361 as I don't own 1 and haven't worked on one either.

 

[biggus]

If you have limiter caps on you won't be able to to turn the screws out 1 full turn! duh! :bang:
There are small red caps on the carb adjustment screws (at least on the 290)... You need to use a drywall screw to remove those red caps and THROW THEM AWAY!!!

Throw them away? I thought they were necessary to keep the settings tight? At least that's what I've been reading on these threads...

 

[Joe Kidd]

Trim the tabs and put em' back on.

 

[old-cat]

I like to keep the tabs on. That way nobody can screw up my saw also I have a tendency to lose my place when adjusting, especially if I have an air leak or carb malfunction. If I don't have enough adjustment I take the cap back off and go 1/2 turn whichever direction necessary, then replace the cap.

 

[tolman_paul]

Throw them away? I thought they were necessary to keep the settings tight? At least that's what I've been reading on these threads...

The caps are our wonderful government via the EPA's way of making sure you don't pollute the air by using too much gas. In reality they often lead to engine failure by running too lean. The screws have springs under them and that spring tension is what keeps the screws in position.

 

[browndd1]

The caps are our wonderful government via the EPA's way of making sure you don't pollute the air by using too much gas. In reality they often lead to engine failure by running too lean. The screws have springs under them and that spring tension is what keeps the screws in position.

so just pull the red tab out of the ms290 high side and don't worry about putting it back in?

 

[sbhooper]

The caps are our wonderful government via the EPA's way of making sure you don't pollute the air by using too much gas. In reality they often lead to engine failure by running too lean. The screws have springs under them and that spring tension is what keeps the screws in position.

Exactly! Pitch them unless you want to feel good about the illegal adjustment you just made!