MS461 carb adjustment with limiters

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MichMich

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Hi gents,

Just received the Walbro HD-50 for my 461 (it had a chinese carb up to now), and noticed the OEM one has limiters installed.

Can anyone tell me how to set it without disassembling the saw?

thanks!
 
You can only do this if the carb is installed on the saw and the saw is running.

The OEM carb should come pre-adjusted with seated limiters. If it is not already on the rich stop point, turn both screws counterclockwise until the rich stop point is reached. Install the carburetor and see how she runs. That does not mean that you don`t need to do a slight correction. If you do this, use a tach to have control. With the seated caps you can turn the adjusting screws a 3/4 turn.
 
wow, does that mean that I can set them "simply" with a small flat screwdriver?
 
haven't it (yet at least), I builded my 461 on a crankcase I bought off eBay

great news for the usability of a small srewdriver
 
Finally got it idling. Low speed/idle is pretty high (3800rpm), but that's the only way I got it somehow stable... But have another problem now. When I go full throttle from idle, she first "blurps" and then go (almost) full power (can't set high speed higher than 11500 rpm), and there's a ton of oil on the soil... (high output oiler in there)

Here's a vid:
 
Clutch engages at 3600. That saw should be able to idle down to as low as 2200. I set them @ 2800. I think spec is 2500. Best bet is to start with a vac/pressure test. Do vac test first.
Something is very wrong.
 
Just swaped the Chinese clutch for OEM one. Of course nothing has changed.
The guy at the Stihl store told me there's a leak somewhere near the cylinder base. Changed the muffler as well, but think I'll get to buy an OEM base, all mufflers (non oem) I bought are empty...

At least she now runs both full speed and idle
Will order pressure/vac tester asap
 
would you have a link to unlimited coil? And to a pressure tester would be solo cool
 
The idle speed is pretty fast and sounds lean to me. You can also hear it when she comes down from full throttle nen, nen, nen, nen.... But as stihl86 already said a pressure and vac test would be a good idea. After that you know if you have an air leak or not. Maybe it would be a good idea to ask your dealer for help, to get the best result and possibly leaking seals changed. (if nessessary)

@PV Hiker
Yes the ignition module is electronically limited, cutoff speed specification is 13.500 rpm.
 
That thing is running like a complete pos. It is so far away from proper running that it's hard to tell whats wrong. TURN IDLE DOWN, open lo screw at least 1/4 turn. Open high screw 1/8 turn...

currently, it is a gutless wonder that will do nothing in wood. It certainly needs fuel...and it could have a leak.
 
Could a leak come from the impulse hose not being fully seated against the case? Just noticed this after having removed the plastic covers

Will disassemble the tank from the case asap, and maybe replace the cylinder gasket.

The crankcase came with the bearing seals already installed (but they seem new), could they also cause a leak?

Could the AM muffler also be (at least) partly part of the problem? The interior of the thing is completely empty

Am also actively looking for a pressure test kit, is there anything beside the Stihl kit?
 
An empty muffler is a good muffler.

There's pressure/vac test kits all over.

mityvac 8500, I believe. Don't quote me on that model being the correct one.
 
Ok, thanks for the inputs!

Will firstly disassemble the saw, to be sure I builded it right the first time.

When I remove the cylinder, do I have to replace the piston rings? They don't have 1 tank through them as for now
 
Why don’t you take the suggestion of doing. vac/ press test. Pulling it apart won’t find the leak. Find the leak, fix it, then go from there. And yes, the impulse must be sealed or the whole system breaks down.
A vac test will find a leaking seal. Pressure will find all others leak. Which you most likely have.
Keep running it that way and risk destroying the top end. A competent dealer might do the test
for a very reasonable price. If they’re idiots, improvise.
 
just ordered the aforementioned kit and Stihl carb adapter, will see in early July

Well, well, well. Need new carb settings now. 3-5 pulls on full choke then blurps. Few more on warm start, fires and dies as soon as chain starts to rev. Could this mean that if there was an air leak it could have been suppressed by rebuilding the saw? Cylinder gasket has also been replaced in the process. OEM was initially installed, but only had a Farmertec on hand. Will try to reset carb asap and see what happens, till I get the pressure/vac test kit.

My oil/fuel mix also doesn't seem optimal. When disassembled (didn't remove the piston from the crankshaft), piston seemed covered with a thin layer of carbon. Am using 50:1 mix. Spark plug is dry.

As for testings, I'm using this tachometer
https://www.amazon.com/gp/aw/d/B000FOOAXY?psc=1&ref=ppx_pop_mob_b_asin_title
 
sounds like a fuel delivery problem now. Aren't machines wonderful? Junk in carb?, impulse problem?

piston crown covered in thin layer of carbon? Normal, although it should have a particular "pattern" on it.

:thisthreadisworthlesswithoutpictures:
 
Started it today after complete disassembly/re-assembly, and cylinder gasket swap. She now runs great. Idle/low speed read is 2850-3400rpm for now, and max speed is 11500-1200. Have an uses OEM coil on it's way, hope it will helps to be more stable
 
The idle speed should not change more than 200-300 rpm while doing a role out test. Turn it slowly from one side to the other and up and down. See what the idle speed does. If it is more (like in your case) there might be a slight air leak or a fuel delivery problem somewhere. But you will see when you get your pressure tester and test the saw.
 
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