Stihl MS271

[mopar3]

Spectre the limiter is in a hole with a notch on the side. The plastic limiter has a tab that you need to line up with the notch. If you turn the limiter you see the tab move past the notch at some point. I did the same thing with the fuel line. I brought the saw in from out side and the fuel just kept expanding as it warmed up. Find a service manual and do a vacuum/ pressure test on the saw to make sure there's no air leaks.


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[mopar3]

You can check all the gaskets crank seals impulse line intake boot all at once.


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[Spectre468]

Spectre the limiter is in a hole with a notch on the side. The plastic limiter has a tab that you need to line up with the notch. If you turn the limiter you see the tab move past the notch at some point. I did the same thing with the fuel line. I brought the saw in from out side and the fuel just kept expanding as it warmed up. Find a service manual and do a vacuum/ pressure test on the saw to make sure there's no air leaks.


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Thanks! I did try to line stuff up, but the H one doesn't seem to have any slot to fit through to come out. The L seems to have a bigger shelf that is longer than the slight recess that I thought it would come through. I'll have to keep messing with it. I don't have the stuff to do a pressure test.

 

[cedarshark]

Standard automotive vac/pressure kit from automotive store will work fine. MityVac makes a good one. Seal up your carb intake and exhaust port, put about -7 psi on the saw(through the impulse line) and watch the bleedoff. There are good threads here on the process. If my saw wont hold a vacumn, I pressure it up and submerge the saw in a sink full of water ....the bubbles will tell you where the air leak(if that is the problem) . Some folks use soapy water in a spray bottles. The MityVac is also useful for testing gas/impulse lines.

 

[mopar3]

Can you post a pick of the carb where the screws are?


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[Spectre468]

Can you post a pick of the carb where the screws are?


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Not right now. I assume pics have to hosted somewhere to be posted on here? So, from the rear of the saw, right hand side of carb, H adjustment screw has red plastic cylinder with tab, L adj screw has white plastic cylinder with tab. Both are inserted into white plastic housing that is attached to the carb, but appears to be held in its place by a spring that surrounds the L screw. There is an opening slit between the H and L adjusters that forms the aperture which the adjusters penetrate. Under this, there seems to be a collar around both cylinders that retains them inside of the white plastic housing. On the L side, there is a groove that runs about 3/4 the diameter of the opening. I thought that I would be able to align the collar with this groove and pull the cylinder free. The collar is wider than the opening and does not pass through. Same with the red H cylinder, but the opening does not appear to have a recessed groove at all. I will consult a service manual and see if there is something that I am missing.

 

[AKDoug]

Any chance you can post a photo?

 

[Spectre468]

Any chance you can post a photo?

No. I'm not very savvy in those regards. Do you have to have images hosted elsewhere to post them here or is it a direct post?

 

[Spectre468]

I just trimmed the tabs off of the limiters and I'm good now. How many turns out on the LA?

 

[mopar3]

The LA is the idle speed adjustment. Do a quick google search and look at a Stihl manual any service manual will work they want you to set the idle speed and the low mix screw together with a tach. You did say you have a tach? Basicly They want to tune the low speed fuel and idle air so that you reduce the idle rpms to spec by adding fuel.

 

[mopar3]

You should do a vac pressure test and make sure theres no air leaks 1st.

 

[mopar3]

What happened on the 271 anyway? When you rebuilt the 360 did you use OEM parts or aftermarket?

 

[Spectre468]

What happened on the 271 anyway? When you rebuilt the 360 did you use OEM parts or aftermarket?

Looks like the guy wants to see if he can get more than 300 for it, says if he doesn't sell it by next week, its mine for 300. I used aftermarket P&C, everything else has been factory.

On the LA, I was wondering if there was a standard setting like the L and H being 1 turn out from seated. I have been messing with both and think that I might be getting close to being where I need to be. Idle is running between 2760 and 2880. I have H set to max out at 13300. Now the next issue. I cleaned out the tank vent as it was plugged up with sawdust. Now its clear, and while tuning, I noticed that there were little bubbles coming from the holes. It was fuel mix. As I understand it, the vent is supposed to suck air IN to equilibrate tank pressure to prevent a vacuum. Maybe I damaged the vent when I cleaned it? Blasted it too hard with air?

I don't have the equipment to perform the vac test.

 

[mopar3]

Your right it only supposed to let air in it's a one way valve. Replace it. So nmurph was asking about where your settings on the high and low ended up when you have it tuned to the correct rpms. I think his idea was to see how far off the standard settings you are to see if the saw needs extra fuel to cover for an air leak.

 

[Spectre468]

Your right it only supposed to let air in it's a one way valve. Replace it. So nmurph was asking about where your settings on the high and low ended up when you have it tuned to the correct rpms. I think his idea was to see how far off the standard settings you are to see if the saw needs extra fuel to cover for an air leak.

Yes, that is exactly right. With tabs trimmed, L is at about 2.1 turns out, total, (so, the original 1 turn, + another turn and a bit) and the H is about 1/4 turn in from the 1 turn. So not very far off, I don't think, and that is with the leaky vent.

 

[knothole]

No, there aren't any "official" criteria, but there is a lot of tradition on the subject.

A semi-pro saw traditionally is built like a pro saw, but it has a lesser performance engine, and usually (but not always) some other differenses, like spur vs. rim sprockets, plastic instead of magnesium in covers etc, or other more subtle differences. Some nicities like an adjustable oiler (just an exemple) may be absent as well.

All saws with a plastic main case and/or a clamshell style engine should be regarded a "homeowner" class saw, regardless what the brand calls it.

I think the majority of the "bad rap" that homeowner saws receive is due to the homeowner. Simple maintenance goes miles towards achieving long service life from a homeowner saw. The plastics/polymers have advanced significantly as well as air filtering and engine quality. They (home owner saws) are not in the same league as the pro's as far as fit and finish goes but if you at least semi take care of them they will last a LONG time. I purchased a new craftsman (Blasphemy!!!!!!!!!!!!!!!!!!!!!!!!!!!) on sale in 2000 for $89.00. 40 cc 18" bar made by (upchuck) poulan. It lasted me 13 years and I sold it for $50.00 on cl. Not a bad return on investment. Just my .02.

 

[mopar3]

Yes, that is exactly right. With tabs trimmed, L is at about 2.1 turns out, total, (so, the original 1 turn, + another turn and a bit) and the H is about 1/4 turn in from the 1 turn. So not very far off, I don't think, and that is with the leaky vent.

Well if the standard setting or starting point is 1 turn out on each your double that on the low speed. Im not a saw expert mechanic but could it be that you are at t 2 turns on the low to cover for an air leak? If I was usure about the saw I would call around to the local dealers or shops and see what they would charge to test the saw. I was able to seal the intake and exhaust with pieces of an inner tube. Then used a fitting to pressure test through the plug hole. But I have a mityvac tool and coolant pressure tester. At 1 turn on the low what does the saw do rev high or dye out?

 

[cedarshark]

I assume that saw has a Walbro HT carb(but I am not sure). I have seen saws with Zama Carbs that required 2 turns out to run correct without an air leak, but not a walbro. I believe you got sound advice above to get the saw vac/pressure tested. Although I believe this is something that would be very beneficial for you to learn, it certainly could be done by a dealer at a reasonable cost if you had the muffler off and carb off to minimize labor costs.

 

[Spectre468]

I have a compression tester en route. Should be able to use it next week. I'll have a new tank vent, fuel line and impulse line by then as well. My understanding was that it might take as many as 4 full turns out to compensate for an air leak, so I didn't feel too bad about the 2 turns. But I ain't no expert.

Behavior noted: Using LA, adjusted idle between 3000-3200, then used L to get down to 2800, as per the service manual. I would encounter a "sweet spot", both at one and 2 turns out on the L, but seemed that at 1 turn, if I were to go counterclockwise even a hairs breadth, the idle would drop down and get erratic, swinging as low as 1600 and as high as 3100ish. LA. Same of the L going clockwise. Couldn't get the idle to stabilize very well, unless I set it closer to 3000. Also, noticed that it was taking too long for chain to stop running when I got off the throttle. Was taking 10-12 seconds to have the rpms to drop below 3400 and then the chain would stop. Had to feather the throttle to get the engine to rev without wanting to stall. I think the new parts and a compression test will be very helpful to resolve the issues with this saw.

 

[MustangMike]

The 360 is a "pro level" saw, and the only one that's ever given me any problems. Stihl ms360 pro.

Sorry about your personal bad experience, but most of the evidence out there supports that in general the Pro level saws out perform and out last the other ones. In addition, the M-Tronic/Auto Tune saws are in a whole new category. I stand by my original recommendation, but the decision is yours. The way I look at it, you can only cut with one saw at a time, may as well be a great one. For cutting over 10 cords a year, the increased productivity would be well worth it. The pro saws also have better air filters, chain lubrication, etc. and are lighter and cut faster. M-Tronic will also remove a lot of headaches.