260 problem

[teakwood]

I have a 10 year old 260 who damage the spark plug like every 2 month (once changed the spool) but now it has started to stutter real bad and to trow out a lot of blue white smoke. What could that be? diaphragm, seals in the carb? I have 2 260s and have owned 4 over the last 10 years, so i have some parts around. Any help is appreciated

[dougand3]

Sounds very rich - may be carb needs cleaning and rebuild kit. Or tuned leaner.
Is compression good? Might be ring is getting worn.

[ZeroJunk]

Yeah, metering needle may be sticking. You can buy a new carb for that saw on eBay for less than $20 U.S. shipped. Not sure about how that works in Costa Rica, but I wouldn't pay $15 for a kit when there is no guarantee that it will fix the problem.

[Weekend_Sawyer]

What does the sparkplug look like when you pull it.

White or chocolate or black.

Are you checking the gap in the sparkplug?

[teakwood]

Well. changed the plug (the old one was black and grey just after 6h) put a new carburetor (a used one from a dismantled saw) in, checked clearance of the spool and flywheel and gave it a try. Works fine but after full throttle the saw keeps turning the chain in idle for about 10 sec and then slows down to normal idle. if i turn out the idle screw the engine stalls in minimum. should i nevertheless buy a new carbkit?? they cost 40$ from the stihl dealer  >:( >:(
Tomorrow the saw will get a full day of use so ill see if she holds up.

Is there a way to check compression on the cylinder without a special gauge? the piston looked super neat thru the intake window

[teakwood]

Definitely wasn't the right repair. The saw still keeps reving in idle and goes up and down. The dealer told me that sounds like a airleak. What do you think? As the saw is 10 years old and has at least 1500+ hours on it he thought that i should change the crankshaft seals and check the piston ring for wear

[motohed]

It sounds to me like an air leak , Check the pulse line and carb boot for cracks , make sure the boot clamp is on good . You may have to do a preassure test on it and check it for a leak down . If it holds 5 to 7 psi for a couple minutes it should be good .

[teakwood]

thanks for the info. The pulse line is? Te small rubber hose who goes from the the carb to the cylinder underneath the rubberboot? How do i make a pressure test?
Bought new crankcase seals, gaskets for the halfs  and zyl and try to find a piston ring. Everything was just 30$ for two saws. Because i have another 10year old saw who has the same sintoms

[motohed]

You can also do it with a vacume pump . you need to block of the carb and intake off with something that will seal them , stihl and husky both make the flanges needed , you will have to block the puls line as well . You can get a fitting , that will go in the spark plug hole with a nipple to attach the hand vacume pump or preassure pump . This should be your first test . I use pressure as I can put soapy water in a spray bottle and check the seals then selves for a leak if you have one . You will need to strip the saw down to be able to see the seals and center gasket , Etc . I also do a check after assembly , just in case something did'nt line up quite right . The pulse hose is the small one , thats from the cylinder to the carb

[teakwood]

definitely was a compression problem. Changed crankshaft seals, gasket on the halfs and cylinder, pulse hose, piston rings were still pretty tight so i didn't change them, gave the whole saw a good cleanup and she seems to run great. haven't tested in the field yet but pretty confident. all the parts were around 20$

Thanks guys for the help

Now i have a second 260 who has the same age and sintoms 

[Weekend_Sawyer]

Thanks for the update, glad you are back up and running.

Jon