Stihl Ms 180 2-Mix Carb issues?

[Dellirium]

Hi,
Back again with another strange phenomenon

Got a Stihl Ms180 2Mix to a repair (no compression)
Got a new Piston, new Bearings, new seals, sealed the cylinder, leak test showed no leakage on both pressure and vacuum.

I did the oil in the cylinder trick, got it running, and i stumbled on a interestjng bit.
Chainsaw will start half choke, on fast idle, works fine, revs up fine, but as soon as i let the throttle it instantly dies

Checked the fuel line, all good
Checked the fuel filter, all good
Tank vent was leaking, solved it, didn’t help
Cleaned the carburetor, new gaskets, etc, leak test, all good

Dissasembled the engine from the case, rechecked the intake manifold and impulse tube, all good

I still cannot find the issue.
It starts only on half choke, revs up when i pull the trigger, on idle dies instantly

I am not very familiar with this type of fixed jets carburetor, that’s why i came here to ask for your help.
Is the issue here? Or i may have screwed up something somewhere else?

Btw, don’t know if may be related. I’m using Aspen 2T mixed fuel after all my rebuilds

Thank you in advance!

 

[SteveSr]

Hi,
Back again with another strange phenomenon

Got a Stihl Ms180 2Mix to a repair (no compression)
Got a new Piston, new Bearings, new seals, sealed the cylinder, leak test showed no leakage on both pressure and vacuum.

Did you bother to clean the aluminum transfer off of the old cylinder or did you buy a new one?

 

[Dellirium]

Thanks for the reply.
None present. The piston ring was stuck to the piston, no scoring on piston/cylinder. I just cleaned it with some scotchbrite
Client opted for a new piston, as he wanted to rely on the saw at his farm

 

[KostasVolos]

Trigger letting off might causing electrical kill off ,due to misplacement ?
Spring of choke lever is "grounded" and if letting off the trigger pushes the choke lever ,in
such way it may be swithing off
the saw .Check the throttle wire

against choke lever and spring of choke lever .

 

[Dellirium]

Trigger letting off might causing electrical kill off ,due to misplacement ?
Spring of choke lever is "grounded" and if letting off the trigger pushes the choke lever ,in
such way it may be swithing off
the saw .Check the throttle wire

against choke lever and spring of choke lever .

Already ruled it out, i’ve disconnected the choke lever wire from the coil, no effect.
Throttle lever metal part is not touching the spring when it happens, i’m currently running it without the air filter housing so that i can see the carb and all the levers and linkages

 

[Old2stroke]

What kind of carb do you have that has fixed jets? Sounds like you don’t have idle fuel, when you cleaned the carb did you verify that fuel was coming out of the idle and transfer ports?

 

[Dellirium]

The carburetor is Zama C1Q- S286D
Only 1 setting screw which regulates additional air in the intake.
As for the second question, i’ll double check that tommorow, i want to say that i have checked it but i have some doubts about it now

 

[Dellirium]

Has anyone tried hooking up a Walbro 215 on the 2-Mix? I know it works on the classic 180, but couldn’t find anything about the 2 Mix variant.
I want to take this route but i am unsure about how the 2 Mix will react to this

 

[stihltech]

The air adjustment does nothing? Is the pulse hole open to cylinder?

 

[Dellirium]

Air adjustment is doing exactly nothing. After 5 full turns it barely keeps the idle running for 2-3 seconds but at really low rpm
Pulse hole is opened, i specified that i took the engine out again to double check

 

[irhunter]

One off-topic question. Are there MS180 2-mix saws in the US, or just MS181?

On-topic comment: while I don't like doing this, sometimes I get to the point of buying a 10 dollar Ebay carb...just as a test.

 

[Dellirium]

I’ll do just that, with a chinese copy of a walbro wt 215

As for the other question, i wouldn’t know. I’m from Romania

 

[KostasVolos]

Has anyone tried hooking up a Walbro 215 on the 2-Mix? I know it works on the classic 180, but couldn’t find anything about the 2 Mix variant.
I want to take this route but i am unsure about how the 2 Mix will react to this

I 've tried .
Thing is that the cheap Walbro WT-215 clones I got they lack
an acceleration pump.
I 've asjusted their metering lever
1.65 mm below the level of carburetor flange (machined surface ) but from idle to WOT the
saw seems to hesitate a bit.
If the L needle is turned out to about 2 turns out ,things get better but the adjustment is too rich and if the saw is left idling it will eventually die out.Not a biggie.
Another issue is that the 2-mix engines have electronically controled ignition modules that
limit the rpms over a certain limit
-14,000 rpm for the MS180 2-mix - as also vary the timing .At wot the timing is advanced ,while at idle the timing is retarded.

I went the route of modding the OEM carb ( ZAMA C1Q S286D ).
Seal the metering snorkel ,drilled
two small holes on its base ,removed the 0.43mm main jet and replaced with a 0.45mm one .
And finally I've adjusted the metering lever to get it running
just slightly rich ( by spark plug reading ) .
Runs much better than the adjustable carb option .

 

[Dellirium]

Thanks for the heads up. I knew that it had a kind of variable timing, that’s why i asked if it could be done.
Do you have any pictures of the 2 drilled holes on the base of the C1Q? I don’t picture it in my head.
The 215 knock off will also come, and i’ll try it too, maybe i’ll get lucky, but it’s also good to have a backup

 

[KostasVolos]

Thanks for the heads up. I knew that it had a kind of variable timing, that’s why i asked if it could be done.
Do you have any pictures of the 2 drilled holes on the base of the C1Q? I don’t picture it in my head.
The 215 knock off will also come, and i’ll try it too, maybe i’ll get lucky, but it’s also good to have a backup

Drill a hole or two
( of 1 to 1.5 mm dia. )
where you see the red dot.
Seal with RTV silicone /epoxy or in other way the opening of the metering chamber snorkel ( blue arrow pointing ) .
This will bypass the metering of the vacuum at the clean side of the air filter and the metering reference will now be the atmospheric pressure - in other
words the mix will not keep leaning out ,as the air filter gets
dirtier.

 

[stihltech]

There is a blocked passage.
I love how everyone wants to get rid of the carburetor. Thousands of not millions running just fine. There are passages in the throat that I clean with a tag wire. And the jet. Pretty reliable carb for the abuse they take. (Work on Amish saws sometime)

 

[turkeybob]

Question for the OP, where in Romania can you purchase Aspen and what is the cost there?
I run quite a few saws in Romania and as it's not my principal home, the saws can sometimes sit around for a while, the Romanian fuel, 10% ethanol is not the best, so would prefer the option of using Aspen, thank you in advance.

 

[Dellirium]

Question for the OP, where in Romania can you purchase Aspen and what is the cost there?
I run quite a few saws in Romania and as it's not my principal home, the saws can sometimes sit around for a while, the Romanian fuel, 10% ethanol is not the best, so would prefer the option of using Aspen, thank you in advance.

Hi,
Go to Hornbach, at the garden section. 115 Ron for 5l, or 25 Ron for 1l

 

[turkeybob]

Thank you!

 

[Dellirium]

There is a blocked passage.
I love how everyone wants to get rid of the carburetor. Thousands of not millions running just fine. There are passages in the throat that I clean with a tag wire. And the jet. Pretty reliable carb for the abuse they take. (Work on Amish saws sometime)

Thank you, i’ll check again, maybe i missed something, it surely has to do with the idle speed jet, since the main jet is as clean as it can be. I have removed it from the carb and made sure that it’s clear of any debris