Building the MS460: Epilogue - The 2nd Saw

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I am thinking that those adjustment screw springs are a must.

Cool beans. You could always send the saw to me. I have plenty of logs to cut up.:p
 
Hey mm with all those issues I ill give you 100 for the saw ........ Lol
 
Can you start the saw without the decompression button?

There's no way I could on my 460. I tried it once and I had to pull on it so hard that I snapped the starter rope.

OK so a quick update for everybody. The saw is a runner, sort of. I'm not happy with the way it's running. I think the carburetor is losing it's adjustment since the limiter tabs have been tampered with and there are no springs on the needles so nothing to keep them from vibrating in or out. I can get it running great and then after a couple minutes it's all wacky again and the needles (particularly the L needle) seem to move on their own. Hard to tell since they are buried in there pretty good with these saws.

I also had to monkey with the high voltage lead for the ignition system as it wasn't carrying spark to the plug. Got that solved for now, I will most likely wind up replacing that lead in the future.

After playing with the position of the clutch side crankshaft seal, I was able to get it to seal up perfectly. (Just tapped it in the bearing a bit to give some clearance from the snap ring groove.) The saw holds pressure and vacuum perfectly and pumps out 167 psi on the compression tester. ==c

The first shortcoming of the aftermarket kit has revealed itself already. The damned decomp valve pops out after every pull! I personally don't need it but sheesh. :rolleyes:

And I desperately need to get a test log to saw on here. I have virtually no saw-able wood to play with now unless I start cutting splits in half!
 
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I can start mine without it.. I bought mine new.

I dont do it on purpose. But I have, just to see how bad it was
 
Can you start the saw without the decompression button?

There's no way I could on my 460. I tried it once and I had to pull on it so hard that I snapped the starter rope.

Both of these will pull over quite decently without the decomp button. I don't even bother with it for a warm/hot re-start.

The elasto-start starter handles make a big difference. Enough so that I have them on everything except my MS230, which is an EZ2Start model anyways.
 
I am thinking that those adjustment screw springs are a must.​

This carb isn't designed for those springs, so I'm going to get new limiter caps for it. I wonder if blue loctite would keep it running for now?
 
I had that Elasto deal on my saw and it tore apart a few weeks before the rope broke. The rope was in good shape too. I much prefer it without, doesn't feel like I'm wasting half my pull by stretching it out.

Dunno if the previous owner did some work on my saw, pretty sure it's stock but it sits just under 200psi compression. My brand new 290 was super easy to crank over in comparison. Even with the decomp button pushed it's tougher.


Both of these will pull over quite decently without the decomp button. I don't even bother with it for a warm/hot re-start.

The elasto-start starter handles make a big difference. Enough so that I have them on everything except my MS230, which is an EZ2Start model anyways.
 
Dunno if the previous owner did some work on my saw, pretty sure it's stock but it sits just under 200psi compression.​

That's a ton more than stock. A stock 460 in tip top shape should pull 155-160psi. If there has been work done to yours, it's a good bet that the ignition timing may have been played with as well and that could make it rather unforgiving to start.
 
This carb isn't designed for those springs, so I'm going to get new limiter caps for it. I wonder if blue loctite would keep it running for now?


I also thought of the blue stuff. Only question - if you go back to "adjust" will it leave any residue that could cause problems. Maybe if you could put it high enough on the treads - this wouldn't be an issue.
 
Can you start the saw without the decompression button?

There's no way I could on my 460. I tried it once and I had to pull on it so hard that I snapped the starter rope.

Seems a lot of people have done that once. ;)
 
The more I play with this thing, the more I think something is actually wrong. Once it heats up it really doesn't want to idle properly. Trying to get the engine to stay running under 3000 rpm is real tough. Thing is, I can't get it tore down fast enough to do a leak test with it "hot". I think I'm going to toss the Chinese crank seals and see what happens. The Stihl service manual for it says either there is an air leak (crank seals, case gasket, impulse line, etc...), or the muffler is leaking. The crankcase pressure/vac test says the case is airtight so maybe I should seal up that muffler! ;lol
 
Hi Master
try preasuring it up in a bucket of water,fish tank works nice you can see everything.
Thomas
 
Hi Master
try preasuring it up in a bucket of water,fish tank works nice you can see everything.
Thomas

There is NO pressure loss from a crankcase pressure test. (even after 2-3 minutes. Also holds vacuum just as well.) I doubt dunking it will tell me anything I don't already know. The issue seems to rear it's head when the saw is hot and as I stated before, there's just too much time involved in prepping the saw for a pressure test to get a reading while it's hot. Going to be a little bit of trial and error from here I think.
 
There is NO pressure loss from a crankcase pressure test. (even after 2-3 minutes. Also holds vacuum just as well.) I doubt dunking it will tell me anything I don't already know. The issue seems to rear it's head when the saw is hot and as I stated before, there's just too much time involved in prepping the saw for a pressure test to get a reading while it's hot. Going to be a little bit of trial and error from here I think.

You know alot more than me but wont a vaccum leak make it run lean? If its only at temp I would think Ignition or someting along that line

JIM
 
Since it's an aftermarket kit have you check the p&c for scoring?
 
You know alot more than me but wont a vaccum leak make it run lean? If its only at temp I would think Ignition or someting along that line

JIM

Ignition would most likely fail under load or at high speed, the saw runs WOT no problem. It's getting it to idle that's the issue. That says air leak or carburetor. I could swap the carbs with the other saw but I'm 99% sure this carb is good.
 
Do the RPM's drop quickly coming out of WOT?
 
Do the RPM's drop quickly coming out of WOT?
I would say it's somewhat "normal" What happens it it will settle in to an idle, break up and die. Requires the throttle cracked to restart. When I get more time, I'm going to swap carbs just to put that one to bed. I'm taking the "good" saw out to play tomorrow so I don't want to tear it apart just yet. ==c
 
I would say it's somewhat "normal" What happens it it will settle in to an idle, break up and die. Requires the throttle cracked to restart. When I get more time, I'm going to swap carbs just to put that one to bed. I'm taking the "good" saw out to play tomorrow so I don't want to tear it apart just yet. ==c

Sounds more "carby" than "air-leaky" to me. Never dealt with it on a saw, but have on a couple 2-stroke dirtbikes. Both had a leak at the jug gasket and would run and idle fine...but the RPMs would shoot to the moon and stay very high after WOT. If it is dropping pretty normal but won't idle that doesn't scream air leak to me...but I'm not an expert and have been wrong before.
 
Sounds more "carby" than "air-leaky" to me. Never dealt with it on a saw, but have on a couple 2-stroke dirtbikes. Both had a leak at the jug gasket and would run and idle fine...but the RPMs would shoot to the moon and stay very high after WOT. If it is dropping pretty normal but won't idle that doesn't scream air leak to me...but I'm not an expert and have been wrong before.
The part that gets me is that it leak tests perfectly. So if the carb swap reveals nothing, then I'm going to have to resort to replacing things one at a time I think. :(
 
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