Needle Valve Limiting Tabs?

[Canyon Angler]

I've seen several of you refer to some kind of needle valve limiting tabs that you need to remove if you want to rich-up the fuel-air mixture after opening up the muffler. (I saw several references to this on Talon's "Big Brutus Dealer" thread ... BTW, does my 361 have a rev limiter??? :bang

Seriously, I looked at the IPL and I don't see anything in the schematic that is labeled, or appears as though it would function as, a stop for the H jet...what exactly are you guys referring to, and how does one remove or defeat it?

This would be on my MS361, like Talon's÷

Thanks, Jeff

Edit: OK, I see there's a special tool (5910 890 4500) for removing those "limiting caps" on the 361, and supposedly the limiting caps (4203 121 2700) are ruined after you remove them once, and they should be replaced. For you guys who service these saws, is that true? Do you need to put in new caps every time you need to adjust the jets?

 

[Four Paws]

Your 361 doesn't have a rev limited coil (from what I understand - maybe Andy will confirm this).

The limiter caps on the carburetor H and L needles have a 'range' of adjustment. They prevent the saw from being set overly rich (EPA) and poluting mother earth. Once you mod your saw, it will need more fuel, and you can't get there with the limiter caps installed - hence the need for removal. Get your saw set where you want it, and then install new caps such that your carburetor settings are now the midpoint of the adjustment range.

 

[Lakeside53]

Just slice the little lock tab off the side, and put them back on... then "middle" doesn't matter. Scratch off the 1/4 - 3/4 carb setting on your air cleaner box - 'cos now you are 1 turn out on both.

 

[Canyon Angler]

Thanks guys.

 

[Gark]

Both Four Paws and Lakeside responses sound like limiter caps MUST be re-installed after removal. Mine were destroyed in the process of removal. Question is- can the saw run fine without problem if the red limiter caps are left completely off? Or, are they needed to keep the H & L needle valves from 'creeping' (turning themselves from operating vibration)? Or are you guys just saying what the EPA would require?

 

[Four Paws]

Your saw will run just fine without them installed. I said to install new caps, but that was the direction of Canyon Anglers question...I would just leave them off. Andy suggested trimming the stops off the caps - trimming or removing the caps entirely will allow the needles to rotate freely, 360 degrees, hence the possibility for them to creep out - although I have not witnessed this. The needles thread through nylon, just like a nylock nut. This prevents them from creeping out. If you are worried, install some springs behind the needles like the older carbs used. FYI - clicker pen springs work well!

 

[Lakeside53]

Sigh... nobody uses search anymore...

On the HD carb (as on the 361, 029, etc) the needles NEED the caps - there are tiny barbs on the caps that stop the caps/needles from coming out. The small friction from these is all it takes. Without them, they can rotate...

And no, they do not thread though nylon.... at least not on any Stihl saws. There is a rubber washer, but that is only to stop air leakage. You can't install springs as there is no head on the needles. Slice the tabs, snap the caps back in, and forget about them. Even if you buy new caps, they are only 50 cents each!

 

[Canyon Angler]

Excellent, thanks Andy. Nice post on the 361 bar studs, too!

 

[Gark]

Thanks alot for the replies.