Stihl 361 tuning

[LogSawyer74]

I'm pretty good at saw tuning. I know exactly what 4 stroking sounds like, and tune to clean up totally under moderate load. My 036, MS360, MS260 and dolmar saws are very easy to tune, really easy to hear it 4 stroke. I've been building lots of 361s lately, and I've found it difficult to tune them. Not sure if it's the quad port cylinder or what, but I can't hear the 4 stroking like I'd hope. The saw I'm having the most trouble with is well broken in, pretty loose. Anything wrong with tuning strictly with a tach? Thinking about just setting it at 13,500 max rpm and forget trying to hear the tune by ear. Is that the correct rpm for a 361? Any help greatly appreciated.

 

[PV Hiker]

I PM'd you the shop manual for the procedure for using a tach to tune. Tach set for high is 14,000 rpm but 13,000 is reasonable and safe for new motor work. I have been using a tach for my 361 to tune and have been working well.

 

[LogSawyer74]

Much appreciated!

 

[blsnelling]

A tach is only useful if you're using all OEM parts and the saw is bone stock.

A 361 is no harder to hear 4-stroke than any other saw IF the muffler has been modded and you can actually hear it.

 

[drf255]

Depending on the version of the 361 you have, you could have a limited coil saw. Does the tuning issue apply to all of your 361, or just your latest one?

Any of the ones I’ve built tune and sound just like every other saw. Like Brad said, tach tuning will be fine if it’s all stock. The gutted muffler ones do “sound” about 1000 rpm higher than they actually are on the tach for me, not sure why.

You can also try to tune it in wood. The highest rpm in the cut usually corresponds to proper tune. This isn’t always exact or safe, but it’s what I’ve found to be true. Once you lean it out, the saw will scream out of the cut but make less power/rpm under load. It’s the only way I tune limited saws.

 

[blsnelling]

It’s the only way I tune limited saws.

This! The ONLY way to safely tune a limited saw is in the cut. Make it super rich, then slowly lean it out until it runs clean in the cut.

 

[sbhooper]

I have mine tach tuned to around 13,600. It is a strong saw. I have never had a problem with it.

 

[BangBang77]

Hey Daryl,

I had a 461 that I couldn't hear 4-stroke, even after installing an unlimited coil.

I gutted the muffler (removed the baffle to match my 460) and enlarged the exhaust hole. I can now hear it 4-stroke clearly. Maybe the baffle had an effect on the exhaust note? I have no idea but I can hear it now...

 

[huskihl]

Hey Daryl,

I had a 461 that I couldn't hear 4-stroke, even after installing an unlimited coil.

I gutted the muffler (removed the baffle to match my 460) and enlarged the exhaust hole. I can now hear it 4-stroke clearly. Maybe the baffle had an effect on the exhaust note? I have no idea but I can hear it now...

Gutted mufflers make it easy to hear. Especially on the 361, as it has a long tube inside that I believe goes from the bottom left to the top right corner and it actually exits towards the rear of the muffler before the deflector blows it forward

 

[LogSawyer74]

Thank you both, helpful responses. I've got the muffler modded, (just an extra hole in the can), but I'll definitely look into pulling out the baffle/tube and see if that helps. thanks again

 

[Vintage Engine Repairs]

Record a video of tuning with the muffler facing the phone camera about 5 meters away. Recordings like this can make the 4 stroking more noticeable.

 

[drf255]

Thank you both, helpful responses. I've got the muffler modded, (just an extra hole in the can), but I'll definitely look into pulling out the baffle/tube and see if that helps. thanks again

Take some BP meds before trying. #1 clusterphuck muffler Stihl ever made. It’s like they intentionally limited the saw with it.

 

[LogSawyer74]

Take some BP meds before trying. #1 clusterphuck muffler Stihl ever made. It’s like they intentionally limited the saw with it.

spot on!! Damn near loose my religion on those mufflers

 

[arto_wa]

I am a homeowner who really can not justify new OEM professional saw prices so instead I have built kit MS 660 & 361 clones and both have worked great for my occasional homeowner use, however I have been struggling with the 361 tuning and appreciate the information you guys have shared here - it's been very helpful!


The first photo is showing the piston of my MS361 clone was taken before swapping in the modified muffler in my second photo.

Changing mufflers sure made a big difference and now it's easy the hear the engine "clean up" when loaded.

I think my tuning was close to right - I just could not hear it with the original (clone) muffler on!


Question:
This is how the very top of the piston looked like before switching mufflers.
I see a band of what looks like "scratching" marks above top piston ring.
Metal to metal contact - not sure what to make of that?






With a Rippa muffler now:





Just cut down about 70 hybrid poplar trees with the 361:





That was the easy part, now the real work begins!

 

[arto_wa]

Bump

So no one has comment about the way the top of the piston looks like in the photo?

I see a band of what looks like "scratching" marks above top piston ring.
Metal to metal contact - not sure what to make of that?

 

[bwalker]

Bump

So no one has comment about the way the top of the piston looks like in the photo?

I see a band of what looks like "scratching" marks above top piston ring.
Metal to metal contact - not sure what to make of that?

View attachment 1016268

That's caused by **** port chamfers of that Chicom cylinder.
You get what you pay for.

 

[arto_wa]

That's caused by **** port chamfers of that Chicom cylinder.
You get what you pay for.

Thank you for the comment,
I suspected that myself, in that case changing to better quality cylinder & piston is not a big deal.

I have heard about Dukes, Hyway, Meteor etc. - any comments on these or others would be welcome please.

Prices for the first two seem to be from $60 to $120 or so.

PS.
The OEM closes equivalent saw is about $900 except a dealer's shelve had none available, the last time I walked by two weeks ago.
Oh well, I could not justify one of those anyway and my trusty old Husky 162 SE will do the cutting with up to 20" bar any day when needed.

 

[bwalker]

Thank you for the comment,
I suspected that myself, in that case changing to better quality cylinder & piston is not a big deal.

I have heard about Dukes, Hyway, Meteor etc. - any comments on these or others would be welcome please.

Prices for the first two seem to be from $60 to $120 or so.

PS.
The OEM closes equivalent saw is about $900 except a dealer's shelve had none available, the last time I walked by two weeks ago.
Oh well, I could not justify one of those anyway and my trusty old Husky 162 SE will do the cutting with up to 20" bar any day when needed.

I believe all the AM cylinders you mentioned are chineseium now.
I would buy this one.
https://www.ebay.com/itm/2338941417...64MggVv/VLp9XcA8Conuzy4Us=|tkp:Bk9SR77cn-zlYA

 

[arto_wa]

The OEM cylinder/piston set looks nice and it's good they have competing part suppliers.

Good to have several options.

 

[LogSawyer74]

I believe all the AM cylinders you mentioned are chineseium now.
I would buy this one.
https://www.ebay.com/itm/2338941417...64MggVv/VLp9XcA8Conuzy4Us=|tkp:Bk9SR77cn-zlYA

Is even Meteor made in China now?? sad...