2 MS460's same problem

[JimL]

Saws arn't a month old, had problem since new.
Same customer. uses stihls mix and oil.

They just die, you be cutting along and they just die.
Ive replaced the modules on both, didn't fix it, replaced tank vents, no fix. Fuel system is tight, no air leaks, not running rich or lean. Runs fine, eccept when it dies. I took one in the woods and it died once mid cut, restarted with choke and finished cut. It also died while idling when i was setting some wedges.


Ideas? Guy has bought saws from us for a long time. Last 046 did the same, turned up as a intake boot..
These saws have the newer intake boot.

 

[sedanman]

Have you tested the saws for air leaks? Pressure and vaccuum? When I have a machine that dies like that I run it with the Zat spark tester on it. You can see if it loses spark before or as it dies.

 

[stihltech]

046

Jim, did you grab a different carb and try it? Beats the heck out of kicking yourself later. I found a few that had debris floating around under the welch plug. I even remove the plug and use a small tag wire to clean the holes to the venturi. It has worked. Found some carbs with a rough finish on the pump face. Can be smoothed with 600 grit and work.
Don't forget the post about the cracked piston.
Also, plugs don't go bad, but I would not guarantee that.
Switch flywheels also, I found 1 bad one.
How about the vent, I have replaced about 3.
After that, it may be internal.

Definitly let me know what you find.

 

[Joey P]

Does the fuel in your state have Ethanol or MTBE??

 

[JimL]

well i put carb kits in both, new tank vents and fuel filters. Run just like the did when he brought them in.

We shal see if they die still...

 

[DirtTroll]

Sounds like the the saws were run to lean and have piston scoring. I've had one with the same symptoms that had scored from running too lean with the fixed intellijet (crap) carb. Take the muffler off and look for scoring with a borescope. I always run my saws extra rich after that saw after replacing the intellijets with older style carburators. Running a little higher ratio of oil to gas probably wouldn't hurt either.

Everyone I know has lost at least one saw (piston & jug) to the intellijet carbs.

 

[lucky]

I have a 044 and 046. If I wanted to change out the intellicarbs, what carbs would I need to be looking for? Do I get them from stihl or somewhere else. How much $? Great thread Thanks!
Lucky

 

[ricksvar]

Like Stihltect said,"Don't forget about the cracked piston."I think that post was on a different forum.

Rick

 

[JimL]

Originally posted by DirtTroll
Sounds like the the saws were run to lean and have piston scoring. I've had one with the same symptoms that had scored from running too lean with the fixed intellijet (crap) carb. Take the muffler off and look for scoring with a borescope. I always run my saws extra rich after that saw after replacing the intellijets with older style carburators. Running a little higher ratio of oil to gas probably wouldn't hurt either.

Everyone I know has lost at least one saw (piston & jug) to the intellijet carbs.

I said it wasn't running lean, I have nbever seen a 46 with a fixed jet carb.

These arn't. I have the equipment to test for air leaks.
Both saws tach out at 13100.
Thats not lean.


I know what a scored piston looks like.
You need a borescope to look at piston scoring?

 

[stihltech]

intellicarb

no such thing as a fixedjet carb on an 044 or 46. They are adjustable, just like ythe previous carbs, just remove the limiters.

Don't blame everything on the carb. When I find scored pistons, it is rarely the carbs fault. Air leaks and bad fuel top the list.
Then there is they operator that won't clean the filter, saw runs rich, so he leans it out. At some point it runs so bad it dawns on him to clean it, but does not adjust the carb because"it runs so good". Then the piston goes out and it is the carb's fault.

Maintenance, maintenance, maintenance!

Stick with it Jim, you'll find it yet.

 

[JimL]

the owner of the saws is more picky about maintenance than i am.

The 046 he owns looks no older than the 2 new ms460's he bought.
its over a year old.

 

[stihltech]

maintenance

The last post was not directed at you Jim. I respect your skills.

 

[tree monkey]

did you check for icing in the carb? just a thoutght

i have had plug wires spark out the side, make sure the primary wires do'nt have bear spots, clean the switch,

hope this helps

later scott

 

[Joey P]

OK I asked before but got no response.

I have been having a lot of problems with customers saws (o46's 066 044's mostly) with the Ethanol that the wonderful government decided to switch to here in CT.

With out getting into a very long winded explaination the saws are icing up because of the ethanol and causing the saw to do exactly what you say. They die suddenly in the cut. I so far have found that winter kits are helping. Just warming up the saw a touch helps.

Im only finding it when it is below 45 degrees out. Not sure if this is your problem. I don't even know if you have ethanol in your fuel or MTBE still. Just a thought and some experience.

---Joe

 

[stihltech]

icing

Does opening the heat door have any effect on these saws? I think this ethanol gas is coming here also.

 

[Joey P]

Even with the heat doors open we are having problems........extra heat doors cut by yours truly seem to help some.......but today was awful......lots of guys with problems. WIll keep yall informed as to whats happenin.

---Joe

 

[Lewis Brander]

To Jim L:

Have you found out what the problem is as yet? Are the carburetors on the saws icing up, because of the ethalol? Like stihltech says we're supposed to be getting it here in NY. Just curious to hear what you found out. Does anyone know of an additive, to add to the fuel mix that might help, that is, if you can't seem to feed enough warm air into the carburetor air intake housing. Thanks. Lewis

 

[JimL]

no icing,
i swapped a carb from a new unit monday for him to try, been to wet to be in the woods this week so i guess ill find out when i hear from him next.

 

[lucky]

Bump.

Jim, anything happened so far?

 

[Wade Huggins]

You know I have went through half dozen of the 046s and had the same problem with a couple of them...........but it was always the fuel tank vent........... saw dust would build up.......I use to run those maxflow filters and the tank vent cover would always get knocked off because the case wasnt covering it to keep the limbs from hitting it in the woods............sounds like air flow to me.... too much or not enough all at once causing it to vapor lock...........just random thoughts good luck..Wade