Stihl MS250 fuel issue

[BangBang77]

Hey guys, a guy I work with brought me a MS250 that is bogging pretty bad.

@atpchas hooked me up with the IPL and SM earlier - many thanks man!!

Tried to adjust it out with no luck so I ordered a new OEM Stihl carburetor from Ebay, which appears to be wrong as it has an additional nipple on the top left of the carb body.

The carb that was on the saw originally was a Zama C1Q-S76, Stihl pn 1123 120 0603. The carb that I bought off Ebay appears to be a Zama C1Q-S75, Stihl pn 1123 120 0602 (even though the Stihl box has 1123 120 0620 stamped on it). This carb is for the easy start version, hence the additional nipple on the top left.

The IPL shows that some 250s came with a Walbro WT-215, Stihl pn 1123 120 0605. The orientation of the carb adjustment screws are entirely different between the WT-215 and the C1Q-S76 and even require a different boot.

Is the WT-215 a direct replacement with the corresponding boot?

This is the first clamshell saw I've worked on and I am ready to drop kick it across the shop at this point...

 

[B.C.]

I'm not sure if the two are interchangeable. I had a 250 with the WT 215 I worked on. I never did get it running to what I thought was 100%. It would change speed when tipped sideways sometimes. I slapped a brand new carb on there and it still wasn't as good as I thought it should be. Bought a brand new one and it had the Zama carb on it. It did the same thing, only worse, it straight up stalled on me once when I was limbing a pine. I concluded that I don't like the 250 and took the new one back and sold the one I was working on that actually somehow ran better. If you can put the WT on there I would but I have limited experience with them. I absolutely hate taking them all the way apart. Taking just the carb off is easy enough though. But taking the orange part off the handle is real fun. Not the worst model I've worked on by far, not by far, but it's not the best design either. I like a lot of the older saws that came apart easy. Anyway, changing the rubber boot if that's what you mean isn't too bad, you do have to take the orange handle part off. There are some youtube videos to help make sense of it if you haven't had it apart yet. One of the toughest parts is the rubber piece where the chain brake attaches on the clutch side. Pretty much need a screwdriver to get it out and back in every time. Good luck, I never was fully satisfied with mine, or the new one, although the power is excellent for the size & weight.

I'm sure someone else has done that swap since the zama carb is so non-adjustable but I haven't. FWIW I don't hate clamshells, I hate crappy seals that wear out too fast though where as I have an old Mac that is literally 50 damn years old that still has good crank seals. And I hate designs that are a ***** to assemble/disassemble. Press in seals are a gift from god though for sure. Those are definitely my favorite but I don't have many saws like that. Would be great to have a list of all the saws that do have press in type seals that don't require disassembly for reference.

 

[HarleyT]

Here, this may help...

 

[LoveStihlQuality]

I have a strong running MS 250. It is the one saw I will loan out. It will cover most needs. I do send canned fuel bar oil and extra chain. If it gets ruined, not out much.

Sent from my SM-T377P using Tapatalk

 

[rocketnorton]

had 230 n 250 hear, both needed lever up a little.

 

[B.C.]

had 230 n 250 hear, both needed lever up a little.

You mean metering lever inside the carb? (From stock I assume) Interesting. Don't remember if I tried that. I have an 023 that runs very similarly. It will change rpm a bit when tipped sometimes.

 

[a. palmer jr.]

Sometimes the carb is not the problem. I've had a few of them that had air leaks around the bottom pan of the engine and the main seals. I've had some that had been put together and looks like they were stingy with the sealer on the pan.

 

[rocketnorton]

You mean metering lever inside the carb? (From stock I assume) Interesting. Don't remember if I tried that. I have an 023 that runs very similarly. It will change rpm a bit when tipped sometimes.

I thought it was odd fix, too.
they were both airtight - pres & vac.

 

[B.C.]

Hey Rocketnorton, what issues did yours have exactly before you upped the meter lever a tad?

 

[rocketnorton]

wouldn't take throttle/bog

 

[B.C.]

I hate having to monkey with the meter lever. Out of curiosity did you check it with the Walbro tool and if so was it right where the tool said it was supposed to be before you adjusted it, or did adjusting it up take it to where it should have been, or did you go higher above where the tool said? I've had multiple that I've had to adjust outside of where the tool says before. Always a giant pita on saws that make it hard to get the carb off too. One nice thing about those stihls.

 

[a. palmer jr.]

On many of the 250 series I just send about $10 to ebay and buy a new carb. I've had 100% good luck fixing them that way and they usually don't even require adjustment...

 

[rocketnorton]

no walbro tool
230 was hit/miss few times.
ended up slightly higher than level. thickness of lever was too high in both. maybe half that.

 

[B.C.]

On many of the 250 series I just send about $10 to ebay and buy a new carb. I've had 100% good luck fixing them that way and they usually don't even require adjustment...

I've tried both. Got a couple cheapo hutzl / farmertecs I tried on the 023/250 I had. Little bit of an improvement on at least one I remember. Got a WT215 from dealer for less than I thought it would be, was around 20/25 I think, that ran pretty good out of the box too but I never did get either to where I thought they should be. I air tested the 250 to no end too.

no walbro tool
230 was hit/miss few times.
ended up slightly higher than level. thickness of lever was too high in both. maybe half that.

So like, half the lever was just above the bottom edge of the tool & half was below basically? Now that you mention it, if that's what you mean, I think I recall a couple now that level with the carb body wasn't quite enough and I had to raise it just a tad.

 

[a. palmer jr.]

It still sounds like a slight air leak if the carburetor can't be adjusted and the idle changes when the saw is tilted..I always run the lever right in the middle, not up or down..