Stihl 661 mtronic wont idle

[Jza]

Hi guys ,bit of a background on the saw . This was a rebuild from bottom up , seals bearings , hoses , manifold .

I installed a new v3 ignition module kit with the white solenoid and orange fuel filter .

I can't get the saw to stay on choke to do the v3 reset , it dies after about 2 secs of idling . The only way I can restart the saw is wot and pull . A big cloud of smoke comes out and will only stay going if I feather the throttle .

I tryed doing a few cuts then let it idle but it was either a lean idle ( chain spinning ) or it would die.

Like I said the only way to restart would be to hold the throttle open and start it without "choke" seems like it's getting way too much fuel .

I cleaned the carburetor with just carb clean , no carb kit.

My guess would be the solenoid , but the one I put in is brand new .

This is my first mtronic build so I'm abit stumped. Any help would be appreciated!

 

[DND 9000]

Inlet control lever misadjusted? Should be flush with the carb body.

 

[ZeroJunk]

Let us know what you find. I have one that I am going to have to rebuild, but the crankcase half is on back order.

I had a head scratcher MS201TCM yesterday and had to replace the wiring harness.

Hope you find the problem quickly.

 

[Jza]

Inlet control lever misadjusted? Should be flush with the carb body.

I'll pull the carb apart and have a look at it tonight !

 

[Jza]

Let us know what you find. I have one that I am going to have to rebuild, but the crankcase half is on back order.

I had a head scratcher MS201TCM yesterday and had to replace the wiring harness.

Hope you find the problem quickly.

Damn that's frustrating! I'm positive my harnesss is fine , I had a look at it when installing and the wires looked good .

I feel like without spending money on doing the process of elimination I'm kinda in a bad place .

I really dont want to admit defeat but If worse comes to worse I'll take it to the shop.

 

[singinwoodwackr]

Have you tried the old solenoid?

 

[Jza]

Have you tried the old solenoid?

The old one was a v2 black solenoid, I heard not to miss match them .

I'm thinking of pulling the carb apart and putting a carb kit in as my next step ! The carb has been sitting around for a year or 2 . I tryed carb cleaner initially and re used all the old stuff.

I'm also thinking once that's done to try run a tank or 2 through it and see if it helps .

I live in New Zealand and parts aren't cheap haha , think a new solenoid is $70 and I'm guessing a new carburetor would be atleast $250

 

[singinwoodwackr]

Odd, I've replaced 2 black with white on 2 different 661s and they run great...fired right up.
I only replaced the solenoids.

If that carb has been sitting that long it probably has crud/shellac inside the passages as well as bad diaphrams .

 

[Jza]

Odd, I've replaced 2 black with white on 2 different 661s and they run great...fired right up.
I only replaced the solenoids.

I threw the old one out haha. Even though the white solenoid is new , could I of rolled an o ring installing it ?

 

[SteveSr]

I threw the old one out haha. Even though the white solenoid is new , could I of rolled an o ring installing it ?

Sounds like you have a carb needle and seat leak or stiff diaphragm. Will the fuel inlet hold 7-10 psi indefinitely? If not you have a leak that needs to be fixed. I would check this before throwing more money/parts at it. It sounds like you are getting more fuel than the M-tronic can compensate for.

The fact that it will run at all should rule out any wiring harness issues.

 

[ZeroJunk]

The fact that it will run at all should rule out any wiring harness issues.

Nope. Although I doubt it's his problem, they may run fine until you put pressure on the handle in the wrong direction.

 

[Vintage Engine Repairs]

Did you pressure and vacuum test it?

 

[Jza]

Bit of an update

Went to the dealer , I get on with him well . He hooked it up and showed me how that side of things worked . He was pretty stumped so I asked if I could try parts to replace and if it works pay for it .

Put a new "green" solenoid in and now it starts in triangle and can perform m tronic calibration if needed .

Need to get out and put it in some wood to break it in and see if it gets better

 

[singinwoodwackr]

Bit of an update

Went to the dealer , I get on with him well . He hooked it up and showed me how that side of things worked . He was pretty stumped so I asked if I could try parts to replace and if it works pay for it .

Put a new "green" solenoid in and now it starts in triangle and can perform m tronic reset if needed .

Need to get out and put it in some wood to break it in and see if it gets better

Fascinating. The bulletins all say use the white one on the 661

 

[Jza]

Fascinating. The bulletins all say use the white one on the 661

I heard that too , the guy looked up on the computer and said it was the newer version.

It works and doesn't flood the saw so I'm happy lol

 

[trains]

My suggestion would have been either check the metering lever and needle and ensure they are ok, if ok, then replace the solenoid, its certainly not the first time I have had brand new parts fail on me.

Good to hear you got it sorted.

 

[Jza]

My suggestion would have been either check the metering lever and needle and ensure they are ok, if ok, then replace the solenoid, its certainly not the first time I have had brand new parts fail on me.

Good to hear you got it sorted.

I let it idle for abit since it's still breaking in . Every now and again the chain would hunt at idle . Maybe a carb kit would be in order ?

 

[trains]

Ok, when breaking in a 2 stroke saw, let it idle to warm up, or idle to go thru to its calibration sequence and then get it loaded at wot in wood to operate at wot at cutting speed of 9500k or so.
Dont let it idle for prolonged periods , it does nothing to help with break in, just let it idle to warm up, and to cool down after wot cutting, or once warm, set for m3 calibration, which you should sort promptly, then cut with it.

That being said.

Ok what rpm is it idling at.
if its below 3500, then I would suggest replacing the clutch shoe springs, you have done a bit of work on this, did you replace them ?
sorry if you did, I did not see where you may have done this.
if the chain hunts, the springs have lost their temper, (yeah lots of funny comments for that word), and they allow the clutch shoes to move out at a lower rpm to engage the clutch.
as its a new rebuild and you have not cut with it, I can only assume that there is no build up of oil soaked saw dust/ wood chips, that can catch the shoes and also cause clutch drag.

They are cheap, like 3 bucks AU a piece, less where you are.

If your investing into new m3 and solenoids I had assumed you had already put a carb kit in it, which is just the metering diaphragm and fuel pump and gaskets, I think you need to order the needle seperately, well over here you need to anyway.

Let us know where your at.

 

[ZeroJunk]

I keep a "guinea pig" solenoid that I "know" is good. Or, know well enough that if it keeps doing the same thing it's not the solenoid.

 

[Jza]

Bit if an update to the update... think it's an airleak . What happens now is the chain spins at idle at a high rpm . If I spray lots of break clean around the cylinder gasket the saw will idle and eventually die .

I've taken the cylinder off and saw liquid between the gasket and clyinder . cleaned the surfaces and used loctite 518 for sealer . Same results , saw will idle really high rpm .

My next guess would be to check the surfaces are true and not warped .

I don't have the tools to check for air leaks so a can of break clean it is .

If all else fails I'll take it to the dealer