MS460 Teardown-Comments Welcome

SixGun · Jan 21, 2016

Put the plug in the wire, rest it on top of the head. Pull it over fast and you should see lots of bright blue sparks

angelo c · Jan 21, 2016

Mike,
first I would:
get the piston to TDC and turn the saw upside down( make sure your cap is tight and the fuel line is connected or plugged.( thinking the case is flooded like was pict above)

don't get frustrated. its a saw, we'll get her going fer sher.

what does the exhaust look like? was it massively spewing black schputz and smoke on the initial runs ?

MustangMike · Jan 22, 2016

No, just sounded like it was breaking up, likely too rich, but it ran fairly clean.

I tried flushing the fuel tank and replacing the filter, but no change. I'm thinking either the carb or coil are not working right, and I've ordered them (instead of stealing from my other saws).

I may be doing some cutting tomorrow before the storm comes, so I don't want to disable another saw.

Have been getting busy with a lot of other things, and it will get worse soon, but I will get it running.

Thanks for your advice, I'll keep everyone posted when I get a chance to mess with it some more.

drf256 · Jan 22, 2016

I'm glad the piston looks OK.

Pull plug, flip saw upside down and rotate motor. See if lots of stuff pours out.

Change plug for sure. I do the plug method six gun uses. Just don't stand an look directly into the plug hole, stand to the side. If you have enough fuel in the chamber, it becomes a flame thrower quickly. Been there and done that trick.

Can't wait to see this beast run. How's your arm feel agpfer all that pulling? Does the decomp pop on every pull? Did you try to plug it for initial startup?

angelo c · Jan 22, 2016

MustangMike said:
I may be doing some cutting tomorrow before the storm comes, so I don't want to disable another saw.

Heck my middle name is " takes parts from other saws" !!!!
Not only to locate a failing part but to confirm a running one too. If a carb and coil fire on a known running saw you can eliminate that area real quick.

MustangMike · Jan 22, 2016

Al, I can pull it w/o the decomp valve, but it is very stout, but only ripped the cord from my hand the day it started.

I plan to be cutting wood today, but I will get to this, just not now.

I'm anxious to cut with it also Al, but lots of other stuff going on.

MustangMike · Jan 22, 2016

OK, I purchased some alligator clips and some wire today, so I pulled the plug, attached the alligator clip to the plug and the other end to the engine, brought the saw into a room with no windows, and I have spark. So now I at least know that the kill switch is not messing up, and likely the coil is good.

So I figured it must be the carb, so I switched back to the original carb (now that I fixed the control lever, and it will activate the choke).

It did not fire, so either I',m badly flooded, or both carbs are bad (a possibility).

I also noticed the fuel tank had some pressure when I removed the cap, another good sign.

So, now I'll try some of those procedures to "unflood" the saw (no, I'm not taking a torch to it!).

Another thing that is bothering me, I don't think it is pinching, but there seems no way to locate the fuel line so that the carb in not pressing against it when you install the carb. You guys also notice this problem with these saws???

SixGun · Jan 22, 2016

SixGun · Jan 22, 2016

SixGun · Jan 22, 2016

Fuel and impulse line should sit like this

MustangMike · Jan 22, 2016

Hard to see from your pic if the back of the carb is contacting the gas line. I also think the green line is a little more rigid, just does not bend out of the way fast enough, but thanks for the pics. As far as I can tell, mine is the same.

MasterMech · Jan 23, 2016

There is the possibility that it isn't getting fuel. Does it smell like fuel Mike?

If it doesn't really show signs of flooding (after several pulls it will be wet inside the muffler and near the outlet, plug will be soaked and you should smell gas) then I'd make sure the fuel and impulse lines are connected on both ends and not pinched shut somewhere. Then give it a shot of fuel down the carb throat and pull it over (no choke, ignition on, throttle should be at least slightly open. The "warm start" position works) and see if it will run on the DIY fuel injection.

If it is severely flooded, you can clear it by opening the throttle, leave the choke and ignition off and pull it over until it stops spewing fuel out the plug hole.

Or try this:

These saws will start and run at 1-1/2 turns out on both carb screws.

And will tune quite easily. Beware tho, tuning a modded 460 to 13,500 (factory specs) will usually leave it pig rich. Even a simple muffler mod will leave it wanting to go much faster.

MustangMike · Jan 23, 2016

My wife goes crazy when I change carbs inside cause it stinks so much, but I did plan on making sure the impulse line is clear when I change the carb. I'm hoping I can just push a thin piece of wire (about 20/1000) through.

When I changed the carb the first time, the second carb did not have a snorkle, and I forgot to seal that hole, so I'm thinking some crud may have been ingested (even though I did not cut anything) and that if it clogged the impulse line, that would cause my problem.

Have been too busy, and not the right weather to mess with it now, but I will get it.

Thanks for the advice.

MustangMike · Jan 23, 2016

I do have a question though. On a Shihl 460, all the way down is Choke. The next position is called "Fast Idle", but if you look at what is going on, the choke is off, and the throttle seems to be wide open. Wouldn't this position work just as well for a flooded engine?

Glock37 · Jan 23, 2016