Help with MS170 adjustable carb mod

[konmaniak]

Hello, was reading the following old post regarding the ms170 carb mod, and I have a few questions:

https://www.arboristsite.com/community/threads/help-unlocking-an-ms170.109112/#post-1718694

I am a little confused about "pulling the brass plug circled in red". I don't actually see a brass plug in that port. The port circled in yellow travels into the port circled in red. Is there normally something blocking the two from each other?

Can someone please explain the instruction for intellicarb slot blocking, and the area for where the screw should block behind the throttle linkage. I'm new to saw breakdowns.

I bought a Raisman carb (Made in Brazil), if it makes a difference.

 

[s sidewall]

Didn't know a ms170 had a intelli carb, got a picture of the fuel mix adjusters?

Steve

 

[HarleyT]

Here is a MS170 carb.

 

[s sidewall]

Oh cr@p, a fixed carb. What does the after market model look like?

Steve

 

[s sidewall]

I didn't even notice that on the one I replaced the engine on. It fired up and ran real well.

Steve

 

[jeremyc]

I did the swap on my ms170 and it made a world of difference on how well it ran and power under load was much better.

The reason you pull the plug And block the other hole is that the carb casting has provisions for different impulse configurations according to engine application. The ports are connected but the “swap carb” typically has a brass plug in the hole that lines up with the MS170.
It appears the carb you bought doesn’t have the brass plug that most have. Mine had a plug (where the picture is circled in red) that I removed and then I filled the other hole with 2 part epoxy to seal it off.


If you pull the air filter housing off of the carb and look on the backside where it connects to the carb, you will see the round hole where the compensating port is. I cut a piece of rubber to fit the hole and just stuck it in there to prevent dust from vetting into the filter housing. If you don’t plug it off, it’s a direct path for air to the carbourater without any filtration.

I will have to look and see what I did with the linkage.

 

[konmaniak]

Thanks everyone. I read that someone reused the throttle shaft from your original carb, so that the linkage wouldn't need any modification. I will try that.

 

[HarleyT]

So what was leaking?

Why are you futzing with the carb?

 

[konmaniak]

Recently someone dropped it out of a tree and the fuel was leaking but just needed to have tank hose re-seated. Nothing wrong with it now, but my work supplies the 170's for us.

If they won't buy us decent saws, I'm going to rip em with muffler and carb mods and get a new one when it dies.