Short lived happiness with my MS360

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Overkill338

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There was a little scoring on the piston when i first got it. The saw had been ran without fuel or air filters as well. I didn't photo the piston so I can't compare then and now. But I think I may have an air leak.

Meteor piston and Caber rings a good way to go? How hard is it to change the seals and bearings on the crank if it's even possible without splitting it?

136322282a091c6e61eef049e6ee5bd1.0.jpg
 
I'd do a vacuum check and figure out the problem before tearing it down. I wouldn't replace the crank seals or bearings unless they are found to be leaking.

Does it 4 stroke with no load or scream? You should be able to hear an air leak pretty easily. If you know what to listen for...
 
I'd do a vacuum check and figure out the problem before tearing it down. I wouldn't replace the crank seals or bearings unless they are found to be leaking.

Does it 4 stroke with no load or scream? You should be able to hear an air leak pretty easily. If you know what to listen for...

It screams. I opened the muffler up and removed the limiter cap on the high screw. I have the high screw at 1 and 1/4 turns out. If it goes in any more it screams like it's going to scatter. I have ordered a tach so I can tune them properly.

I can't seem to get it to "4 stroke" or my ear just isn't trained to it.

Ryan if it does ok on compression and vacuum tests, would you call it ok to keep running it. I have changed all my fuel mixes to 40:1.
 
You’ve got issues, yes. Go through what ya can and research old posts on procedures for help. I’d personally replace most rubber components and go through the carb.
1125 series are great saws and usually worth fixing right. Easy to work on, too.
 
You should be able to get it to 4 stroke. Keep turning that H screw out. You should hear the rpms drop as it turns out. You need to spend some time learning the what you're listening to. Once you have the knack, checking the tune will be second nature. You'll hear saws running from the other side of the neighborhood and know right away if it's too rich. A tach is kinda cool, but your ear is the best tool.
 
Also, adding more oil (40:1 instead of 50:1) is great for the bottom end, but it actually leans out the mixture that gets combusted. More oil means less fuel. It's not a big difference, but it's not like you can overcome an air leak by adding oil.
 
It is running lean for sure, I would replace the seals, intake boot, pulse line and fuel line if it was mine. they are good saws. richen it up on the H side too. until you learn to hear it flutter, turn the h side in until it screams then back it out 1/2 to 3/4 a turn that should get you safe
 
Inside the carb is a little fine mesh screen. It acts as a 'last resort' fuel filter. When bozo the clown does his performance mods and removes the air filter & fuel tank filter this screen ends up collecting all the crud. My guess and I ain't Einstein by any means is that this screen could possibly, maybe, perhaps need cleaning. When you do so you may find other components need a clean out too. I like MS360's, worth giving it a little TLC.
 
Inside the carb is a little fine mesh screen. It acts as a 'last resort' fuel filter. When bozo the clown does his performance mods and removes the air filter & fuel tank filter this screen ends up collecting all the crud. My guess and I ain't Einstein by any means is that this screen could possibly, maybe, perhaps need cleaning. When you do so you may find other components need a clean out too. I like MS360's, worth giving it a little TLC.

I bought it as a "parts saw" as the previous owner said it wouldn't run. The first thing I did was go through the carb and give it a well needed cleaning. You are right though, that screen was completely blocked.
 
Don't just randomly starts replacing parts, even the rubber ones. Vac/pressure test and visually inspect all rubber parts. Replace what's needed. Any used saw should be gone through entirely and EVERYTHING inspected.

No, don't even start the saw again until you've repaired the new damage and fixed whatever is wrong. No amount of scoring is ok. It creates high spots and is even more likely to score the next time you run it. You have an issue if it won't 4-stroke at 1 1/2 turns out.

You MUST develop an ear to tune if you're going to run modded saws.

https://www.arboristsite.com/community/threads/chainsaw-tuning-101.250802/
 
Thanks for the videos Brad.

So I need it to sound like my 241 does at WOT. I may try it once more and take a video for your professional years.

If I have to tear into it, I'm thinking about having it ported too. I've considered one of those cheap cylinders on eBay to try porting myself. One company called Hywy parts I think it is, wants to send me a piston and cylinder ,and if I'm happy, I can pay them later lol Seems like they might go in the hole with those business practices.
 
Don't just randomly starts replacing parts, even the rubber ones. Vac/pressure test and visually inspect all rubber parts. Replace what's needed. Any used saw should be gone through entirely and EVERYTHING inspected.

No, don't even start the saw again until you've repaired the new damage and fixed whatever is wrong. No amount of scoring is ok. It creates high spots and is even more likely to score the next time you run it. You have an issue if it won't 4-stroke at 1 1/2 turns out.

You MUST develop an ear to tune if you're going to run modded saws.

https://www.arboristsite.com/community/threads/chainsaw-tuning-101.250802/
Inspect, test, then replace if necessary. I personally have not found few fuel or impulse lines from well-used “parts saws” with running issues to be worth using again. Even a quick inspection can miss a leak.
Recently we’ve run into some ripped intake boots on 1138 and 1128 series. Before those I hadn’t seen one in years.
 
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