On the top cover of my MS180 where you adjust the carburetor it says "LD" and has a plus and a minus by it. Anyone know what the LD means?
MS180
- Thread starter a. palmer jr.
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I didn't see where it mentions an LD screw. It has the + side as being turned clockwise so it must be the idle speed screw rather than the Low side adjustment which this carb doesn't seem to have. I guess it's now moot since I just ordered a fully adjustable carburetor for it...
I think it’s the air bleed screw. Out is leaner in is richer.
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Can you put up a pic of this?
I think you're right. At any rate I just installed a new fully adjustable carburetor and got the saw running this morning.
I saw plenty of them on ebay for sale, it's the one with the silver colored screw on the adjustment side but high in the corner nearest the engine. I don't think it was made to be adjusted but the one time. When I turned it nothing changed so it might be defective.
It's the Zama C1Q-S57.
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Yeah, but a pic of the LD lettering.
LD=Leerlauf-Drehzahl
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Here is the pic of one here at my desk.
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That's easy for you to say!!
Yes it is german.
Found it.
This is the BIS (balanced idle system) carburetor with an air bypass channel.
slow idle speed: The LD screw closes the air channel nearly completely.
higher idle speed: The LD screw is turned out a little bit
highest possible idle speed: The LD screw is turned out completely
This is the BIS (balanced idle system) carburetor with an air bypass channel.
slow idle speed: The LD screw closes the air channel nearly completely.
higher idle speed: The LD screw is turned out a little bit
highest possible idle speed: The LD screw is turned out completely
So, I guess there's no adjustment on it except the idle speed. I suppose you could tear into it and adjust the fuel input valve a little higher or lower to influence the mixture a bit?
Yes you`re thinking right. But playing with the inlet lever is very tricky. You can also screw in a differend sized jet, but that`s also tricky.
I just got done putting together another Stihl 017 (018) chainsaw. Started life as an 017 but I changed the piston/cylinder/coil to make an 018 out of it. It idles good but bogs down on the high end so I guess the next thing is to put a fully adjustable Walbro on this one too.
The jets are easy to change & are available in 0.025mm increments. All the ones I've worked on have needed the jet taken up a size or 2 to get them running properly (the newer ones are usually worse). Tach the saw & if it's lean try the next size up. I tend to just drill them out to the next size up if I don't have an appropriate replacement & this has always worked well for me.
I already have two Walbro adjustable carbs ordered, should be here this week. I did one a couple of days ago and have this one complete except for the carb and the saw I bought at the flea market, still need to go through it, will replace it also but I think it's an 017 instead of an 018. I have several little saws so I'll probably end up selling the Stihl..
Okay, I got one of the carbs today and installed it on the 017-018. Pulled on the cord about 100 times at different carb settings and it wouldn't hit even once. For about an hour I thought I had it flooded then got the bright idea to change the new spark plug out with an old one and it hit on the next couple of pulls! I guess it's true about what you guys say about Chinese spark plugs, that's what was in it. Replaced with a kinda rusty NGK plug, guess I'll leave it in the saw since I don't have any new ones in the shop except other Chinese ones. Someone will probably tell me the NGKs are made in China also...
China made plugs are hit or miss but over the years I have found every make of plugs to stop firing at some point, checking the spark became my number one first thing to check when an engine won`t fire after a dozen pulls over.
