026 wot surge

[volks-man]

here we go again with the 026.

the background info:
this is an older 026 with old style air filter and tank vent. got new chain, new oiler, new airfilter, and cleaned up moderatly. had the muffler off during cleanup and the cylinder looks great. running on fresh mix of super93 and stihl ultra.

saw starts easily and is runing pretty good but seems to not be revving very high.

using my el-cheapo tach after warming up and making a few cuts i see it is only turning 8500-9000. my manual says 14000 max. i turn the screw slowly and it rises. thing is after i reach 10000-10500 the rpms start to rise by themselves. rpms below this figure seem to hold steady forever. i stop turning the screw and the rpms steadily rise. i turn it back out a little and they continue to rise. the tach got up to just under 14000 before i let off the throttle. thinking it was something i did i start over with the h screw at one turn out. same results but i let it rise hoping it would plateau. 14000 came and went. the tach refreshes uber slow so i really don't know how fast it turned before i stopped.
i suspect air leak and pull filter and cover off. sprayed small amount intake cleaner (the kind for cleaning car/truck throttle bodies and has lube in it.) behind carb and it nearly kills the saw. i spray the throttle shaft on both sides and it seems to do the same thing but i don't really know if it is spraying past to the back of the box.

questions:
if the shaft is leaking, what is the cure?

if the carb is leaking air where it meets the box, what's the cure?

what am i missing?

any help, tips, suggestions appreciated.

 

[THALL10326]

here we go again with the 026.

the background info:
this is an older 026 with old style air filter and tank vent. got new chain, new oiler, new airfilter, and cleaned up moderatly. had the muffler off during cleanup and the cylinder looks great. running on fresh mix of super93 and stihl ultra.

saw starts easily and is runing pretty good but seems to not be revving very high.

using my el-cheapo tach after warming up and making a few cuts i see it is only turning 8500-9000. my manual says 14000 max. i turn the screw slowly and it rises. thing is after i reach 10000-10500 the rpms start to rise by themselves. rpms below this figure seem to hold steady forever. i stop turning the screw and the rpms steadily rise. i turn it back out a little and they continue to rise. the tach got up to just under 14000 before i let off the throttle. thinking it was something i did i start over with the h screw at one turn out. same results but i let it rise hoping it would plateau. 14000 came and went. the tach refreshes uber slow so i really don't know how fast it turned before i stopped.
i suspect air leak and pull filter and cover off. sprayed small amount intake cleaner (the kind for cleaning car/truck throttle bodies and has lube in it.) behind carb and it nearly kills the saw. i spray the throttle shaft on both sides and it seems to do the same thing but i don't really know if it is spraying past to the back of the box.

questions:
if the shaft is leaking, what is the cure?

if the carb is leaking air where it meets the box, what's the cure?

what am i missing?

any help, tips, suggestions appreciated.

Need to get the crankcase pressure and vac tested to get that out the way. If the crank seals are leaking all the adjusting isn't going to help much. Richening it way up, as when it was running 8500-9000 rpms would cover up a crankcase leak somewhat but you still have a problem. If your going to get into piddling with saws you would be wise to get a pressure and vac tester. Will save you alot of headaches...

 

[volks-man]

Need to get the crankcase pressure and vac tested to get that out the way. If the crank seals are leaking all the adjusting isn't going to help much. Richening it way up, as when it was running 8500-9000 rpms would cover up a crankcase leak somewhat but you still have a problem. If your going to get into piddling with saws you would be wise to get a pressure and vac tester. Will save you alot of headaches...

who's piddling?
i just might go pro and challenge you!

seriously, i have a vac pump. never used it on a saw though. guess i'll read up on vac and pressure testing.
since we are just talkin here, what do you do about the throttle shaft? it would appear i have a leak at least there, if not the crank seals too.
why does the saw only surge above 10K?

 

[THALL10326]

who's piddling?
i just might go pro and challenge you!

seriously, i have a vac pump. never used it on a saw though. guess i'll read up on vac and pressure testing.
since we are just talkin here, what do you do about the throttle shaft?
why does the saw only surge above 10K?

Welp if you test the crankcase and it holds pressure and vac that tells you real quick the problem is elsewhere.

If the throttle shaft is loose in a worn carb body you pitch the carb, really no way to fix that.

Thinking here though, if you set the H and L out one turn that saw should be fairly close providing everything else is in order. You shouldn't have to adjust much from those settings, if you do then something surely isn't right.

Also is this a 026 or a 260? I ask because I don't think a 026 runs 14,000 like the 260, my book says 13,000 max for the 026...

 

[volks-man]

i forgot to mention.
the carb was once bolted on (not by me) with one of the wires that run by it trapped behind it against the plastic on the intake boot side of the carb. just barely caught on the edge. could i be getting a leak because of some distortion?
that would explain the resuts of my leak test.
when i removed the carb to fix this there was no gasket behind the carby. should there have been?

 

[volks-man]

Welp if you test the crankcase and it holds pressure and vac that tells you real quick the problem is elsewhere.

If the throttle shaft is loose in a worn carb body you pitch the carb, really no way to fix that.

Thinking here though, if you set the H and L out one turn that saw should be fairly close providing everything else is in order. You shouldn't have to adjust much from those settings, if you do then something surely isn't right.

Also is this a 026 or a 260? I ask because I don't think a 026 runs 14,000 like the 260, my book says 13,000 max for the 026...

the saw is the oldy 026
i am looking at an 024, 026 manual supplied by an AS member. it has specs for 024, 024s, 026. the 024 and 024s say 13000 and the 026 says 14000. do i got an old manual or something?

 

[THALL10326]

the saw is the oldy 026
i am looking at an 024, 026 manual supplied by an AS member. it has specs for 024, 024s, 026. the 024 and 024s say 13000 and the 026 says 14000.

Interesting, I'm looking at mine right here , it says 13,000 for the 026 and 14,000 for the 260.

Makes no nevermind though, rpms levels aren't the issue with that saw from what your describing. Check that crankcase and go from there..

 

[Lakeside53]

Spraying a volitile cleaner anywhere near a carb is inconclusve at best. I've NEVER seen an 026/260 with a shaft worn enough to do anything to the operation...


Do the pressure testing...

Look at your carb -is the metering diaphragm stiff as a board?

Are your H & L screws NEAR 1 turn out?

There is NO gasket behind that carb; there is a metal ring in the boot throat.

14k is fine on an 026 or a 260 - Ignore the obsolete service manuals - look only at the "test and settting data".... latest version.

 

[THALL10326]

i forgot to mention.
the carb was once bolted on (not by me) with one of the wires that run by it trapped behind it against the plastic on the intake boot side of the carb. just barely caught on the edge. could i be getting a leak because of some distortion?
that would explain the resuts of my leak test.
when i removed the carb to fix this there was no gasket behind the carby. should there have been?

No need for a gasket, the carb seats right aginist the intake boot. Take it off again and see if the wire push a groove into the boot where the carb seats against it, not likely but worth a look see..

 

[THALL10326]

Spraying a volitile cleaner anywhere near a carb is inconclusve at best. I've NEVER seen an 026/260 with a shaft worn enough to do anything to the operation...


Do the pressure testing...

Look at your carb -is the metering diaphragm stiff as a board?

There is NO gasket behind that carb; there is a metal ring in the boot throat.

14k is fine on an 026 or a 260.

Hello speedy,LOLOL

 

[Lakeside53]

but... I edited it so you're late again...

 

[THALL10326]

but... I edited it so you're late again...

I'm gonna have to get me satelite net so I can almost keep up with your Fios, grrrrrr,haha

 

[Lakeside53]

I'm just dsl... maybe it's just me that's faster?:greenchainsaw:

 

[THALL10326]

I'm just dsl... maybe it's just me that's faster?:greenchainsaw:

You haven't got Fios yet, that suppose to be blazing fast. Verizon tells me its coming soon, been two years now, hope its faster than they are,grrrrr

 

[volks-man]

no sat. no way!

You haven't got Fios yet, that suppose to be blazing fast. Verizon tells me its coming soon, been two years now, hope its faster than they are,grrrrr

i have wildblue sat internet.
do not get it unless it is your only option other than dial-up.
not quite living up to the hype. speed varies wildly throughout the day as it is a shared connection. rain fade nocks you down or out all too easily. fair access policy limits your use to x amount of gig per rolling 30 days.

just trust me!

 

[Lakeside53]

so.. speedly.. what are the answer to my q's?

 

[THALL10326]

i have wildblue sat internet.
do not get it unless it is your only option other than dial-up.
not quite living up to the hype. speed varies wildly throughout the day as it is a shared connection. rain fade nocks you down or out all too easily. fair access policy limits your use to x amount of gig per rolling 30 days.

just trust me!

Thanks for that info. They contacted me about getting WildBlue. Some guy named Tony told me we can hook you right up. Told em I'd ponder on it. No need to now, thanks..

 

[volks-man]

so.. speedly.. what are the answer to my q's?

if you mean me:
i don't have a pressure tester. i need to make the block-offs for the vac.
i am in the house dreading taking the darned thing apart again, it is outside.
i have no idea how to check the diaphram.
and the carb is still on so i can't see if the ring is in there.
sorry for my lack of preparedness to your response.

 

[THALL10326]

so.. speedly.. what are the answer to my q's?

LOL, where are the questions???

 

[THALL10326]

if you mean me:
i don't have a pressure tester. i need to make the block-offs for the vac.
i am in the house dreading taking the darned thing apart again, it is outside.
i have no idea how to check the diaphram.
and the carb is still on so i can't see if the ring is in there.
sorry for my lack of preparedness to your response.

He's got that DSL cooking tonite,haha