MS180C has something caught in its throat...

[tomscott]

Yes, it's just an MS180, just a plastic fantastic trim saw, but we all wonder if we can get "more". There is an insert that goes in the intake throat that can only restrict air flow. Maybe it helps control spitback, I can't think of any other purpose. Just wondering if anyone else has results of removing. Currently with the the spark screen removed and the muffler louvers opened up slightly it will still four stroke occasionally out of the wood. With it running so well with the existing fixed jet carb, I'm not really anxious to make a mod that will require getting an adjustable carb.

First pic is with restrictor next to throat:


And installed:


And finally a close up showing just how restrictive this thing is:


If the best answer is "just leave it alone", that's fine, it carries its weight in the line-up just fine. I'm actually kind of impressed by it when I cut a larger log, usually happens just because it is the saw in my hand at the time, and it is good to run it hard every now and again.

 

[BuckthornBonnie]

Not sure on that intake setup. Does it help maintain the shape?

You're right about the muffler screen on these things. 170s, too.

 

[Adirondackstihl]

Upgrade to a WT-215 for $30.
I usually ditch that plastic piece.
I usually open the mufflers up a decent amount.

 

[Czed]

Upgrade to a WT-215 for $30.
I usually ditch that plastic piece.
I usually open the mufflers up a decent amount.

+1 these little suckers will suprise you with a little work bump the timing a little too.

 

[fearofpavement]

I have a couple of those, I just run them stock. Great limbing saw.

 

[Adirondackstihl]

I sold my modded one for $100 a few years ago.
Kinda wished I'd kept it.

 

[tomscott]

Not sure on that intake setup. Does it help maintain the shape?

You're right about the muffler screen on these things. 170s, too.

It doesn't do anything but restrict the intake. I was stretching to suppose maybe they did something maybe to dissuade spitback.

Upgrade to a WT-215 for $30.
I usually ditch that plastic piece.
I usually open the mufflers up a decent amount.

With an adjustable carb I would ditch it in a heartbeat. The saw is so useful as is for what it does, I will likely not fool with it for now, but I am curious, are any modifications need to drop a WT-215 in there?

+1 these little suckers will suprise you with a little work bump the timing a little too.

Good to know, but swapping to an adjustable carb would be as wild as I need to go for this thing!

I have a couple of those, I just run them stock. Great limbing saw.

Probably best answer for me, don't need another project! Does the limbing and then some as is. The fixed carb is almost perfect tune for where I'm at, especially with the spark screen tossed and louvers bent open just a tad. Muffler has the nice grey cast behind the louvers now, not a train wreck of burn't oil.

Still curious how easy a the WT-215 drops in... If I don't need to bend up new linkages or anything, if it is just drilling a H and L access hole in the plastic, I might treat myself.

 

[tomscott]

Ok, so the whole reason I got into this a few weeks ago was that the carb started running lean. Disassembled in my parts washer, reassembled, ran great, so didn't mention above. After using for a day or two more after my previous posts, it started the lean act again. Seemed like the fuel pump wasn't keeping up, and I had tested the fuel pickup/filter, flowed fine. So, instead of a carb kit, I went with the @Adirondackstihl "best answer"; I ordered up a WT-215.

The AS thread ( http://www.arboristsite.com/community/threads/ms180-adjustable-carb.74899/ ) gave the important info, block off the open impulse hole in the carb base and pull the brass plug to mate with the impulse opening in the saw case. I'm adding some of my own notes here in case someone is a little newer at mods and wants some more details that aren't in that thread.

1) I used Permatex #2 to block off the impulse hole in the carb base, much easier than the overkill of JB Weld.

2) As mentioned in the AS thread, the throttle plate does not open all the way without using some sort of spacer in the trigger linkage slot. I opted for 14 gauge copper wire, was the perfect diameter for the slot and provide full throttle opening:

3) I opted to keep the WT-215 as is and not replace the cover with the "Intellicarb" cover. Kind of comical, my late 60's McCulloch has the whole carb under the filter, and Stihl invents a marketing word that infers great technological achievement. I decided I am fine with knowing the air filter is getting clogged because it is starting to run fat. Pic with carb installed showing traditional metering cover and adjustment screw locations:

4) I went for the "eyeballing it" drilling method with a Dremel and burr correction device. Worked out great. Here is the hole that will cause the most angst, idle adjustment through the plastic handle and side of case:

Directly above you can see the side of the pair of holes (well, 1-1/2 holes...) for the mixture screws, with a slight handle graze.
5) Don't know if they are all this way, but pleasantly surprised to find my airbox had all three adjustment holes already placed, and they lined up perfectly with the WT-215:

6) Since I was not using the Intellicarb cover, I did stuff airbox opening for it with filter material. I also tossed the intake restrictor I mentioned previously since I can now tune it properly.

Started right up with L at 1-1/4 turns and H at 1 turn out. Needed a little richer on the low before the H would tune out nice, but finally runs right without worrying about burning it down! The high is more sensitive than most other saws, 1/8 turn in on the H will take it from blubbering four stroke to no four stroking, but within a few test cuts, it was right on. I think I ended up around 14,000 rpm, have a light four stroke out of the cut. Any richer than that and the power started falling off in the wood.

Thanks to all those who posted before that made this an easy mod!