066 does not have a fast idle on cold start

[Broken bar]

I bought a older 066 it does not go into a fast idle when i move the choke to the cold start position i took off the air cleaner and it does not seem to even be able to go to partial choke its either open or closed when i move the choke lever to the cold start position i dont feel any detent in it its an older 066 but runs pretty good when i finally do get it started would there be any reason some one would have modified this saw to not idle hi like other smaller stihls do its my first bigger saw i dont know alot about it if anyone has a suggestion id appreciate it thanks

 

[Wood Doctor]

I bought a older 066 it does not go into a fast idle when i move the choke to the cold start position i took off the air cleaner and it does not seem to even be able to go to partial choke. It's either open or closed when I move the choke lever to the cold start position I don't feel any detent in it. It's an older 066 but runs pretty good when I finally do get it started. Would there be any reason someone would have modified this saw to not idle high like other smaller Stihls do? It's my first bigger saw. If anyone has a suggestion I'd appreciate it. Thanks

I've run into this same problem with my friend's 066, so I decided to rejuvenate Broken Bar's thread. When you move the switch shaft control from choke to fast idle, the carb does not open up the throttle or leave it partially open from the choke position. So, it stays at a low idle position. I've also noticed that the trigger interlock that is supposed to be down when choked does not stay there when moved to fast idle. Neither my 046, MS660, nor any other Stihl that I own does this. Any idea what is causing all of this and how to fix it?

 

[Mastermind]

The master control lever is suppose to have the fast idle lever on it. If you have no fast idle.....you have a broken master control lever.

 

[ChoppyChoppy]

Not sure if it was an option? I've had 4 or 5 660s/066 and none had the "1/2 choke". It wasn't anything broken that I could see.

 

[ladrhog]

Red = bad
Black = good


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[Wood Doctor]

Red = bad
Black = good
Sent from my iPad using Tapatalk

Mine is like the black one--good. What I believe is supposed to happen is that the throttle is supposed to be open about 20% on both the choke AND the fast idle position. When you switch from choke to fast idle, the choke opens up but the throttle position remains fixed. In my case (and others reporting here), the throttle is never set in a 10% to 20% position. So, you never get a fast idle when switched off choke.

I wonder if anyone has ever made an adjustment or part modification of some sort to get the 10% to 20% fast idle throttle position? Bending the throttle wire fails because then there is no release down to low idle when you take it off fast idle with the trigger.

 

[tacomatrd98]

Dumb queston but, are you pulling the throttle lever to WOT before you set the choke? If you are forcing the lever down without opening the throttle first it will not open the throttle plate on it's own. Sequence goes, hold throttle open, set to choke(bottom) position, tug till it pops, without touching the throttle bump it up one position to half choke/fast idle. Once it starts blip the throttle and it resets to base idle.

 

[hseII]

Red = bad
Black = good


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I've seen red ones work pretty good: it's a matter of worn out, not color

 

[Mastermind]

The red one is missing the fast idle cam silly.

 

[hseII]

The red one is missing the fast idle cam silly.

Don't mean it's bad though.

What I mean is, if everyone believes the red ones are "bad", next thing you know, no one will buy a saw in the classifieds if it has a red master switch, because they read on the intertube that red ones are bad.

There is a difference, but the red one isn't bad just because it doesn't have the fast idle position.

 

[Mastermind]

Well, it did have a fast idle......but is broken off.

 

[cgraham1]

Well, it did have a fast idle......but is broken off.

It doesn't matter what color it is....

 

[ladrhog]

Thanks cgraham1 for putting the circles on my picture. I have a 066 on the bench that was doing the same thing.

 

[cgraham1]

Thanks cgraham1 for putting the circles on my picture. I have a 066 on the bench that was doing the same thing.

No problem. I got the feeling some people weren't quite getting it.

 

[Wood Doctor]

Mastermind, et al., I agree that the broken off portion of the switch rod will cause the loss of a fast idle. I have no fast idle and a perfectly good switch rod with nothing broken. This occurs after setting the choke correctly and moving to fast idle position. The throttle is not opening up partially at either choke or fast idle position. It remains closed in the slow idle position at either setting. In short, you would think that it is operating correctly when it is not.

As posted earlier: "Sequence goes, hold throttle open, set to choke(bottom) position, tug till it pops, without touching the throttle bump it up one position to half choke/fast idle. "

Fast idle never occurs. Base idle is all that exists at either choke or fast idle position. You can see this by using a flashlight with the air filter and cover removed. The throttle port valve on the carb never moves. It does on my 660, 046, etc., but not on my friend's 066.

 

[RiverRat2]

Mastermind, et al., I agree that the broken off portion of the switch rod will cause the loss of a fast idle. I have no fast idle and a perfectly good switch rod with nothing broken. This occurs after setting the choke correctly and moving to fast idle position. The throttle is not opening up partially at either choke or fast idle position. It remains closed in the slow idle position at either setting. In short, you would think that it is operating correctly when it is not.

As posted earlier: "Sequence goes, hold throttle open, set to choke(bottom) position, tug till it pops, without touching the throttle bump it up one position to half choke/fast idle. "

Fast idle never occurs. Base idle is all that exists at either choke or fast idle position. You can see this by using a flashlight with the air filter and cover removed. The throttle port valve on the carb never moves. It does on my 660, 046, etc., but not on my friend's 066.

The master control lever is suppose to have the fast idle lever on it. If you have no fast idle.....you have a broken master control lever.

Not so fast Grasshopper!!!! I have seen this before

My Nephews 066 was doing the same several yr ago, I installed a new MCL.. it still did the same thing!!!

I played with it a few hours and this is what I found, and how I made a temporary fix, If the master switch is complete with no missing parts??? I found that the grooves in the Tank handle where the throttle trigger rides are worn/wallowed out, which allows a bit of radial movement (wobble) and does not allow the fast Idle position to latch properly and it slides right to the run/idle position, bypassing fast idle...., Here is what I did to make a temp repair until you can find another tank/handle. I took the rear handle cover apart to get the trigger out. I took a small Plastic drinking straw that the ID barely slides over the ends of the metal pin that protrudes on either side of the trigger. I cut two sleeves from the straw that were just long enough to cover the pins and bush the worn slots in the trigger handle (reduces wobble). reassemble and give it a whirl!!! If it is too worn for the drinking straw bushings to work I've taken a big ty-wrap/cable tie and install loosely around the handle, adjust to give you a fast idle. Once she pops on cold choke start, slide the ty-wrap in place crank then blip the throttle and the ty-wrap once you get it adjusted to work for your liking and cut wood.

There's always more than one way to skin a cat

 

[Wood Doctor]

Not so fast Grasshopper!!!! I have seen this before

My Nephews 066 was doing the same several yr ago, I installed a new MCL.. it still did it!!!

I played with it a few hours and this is what I found, and how I made a temporary fix, If the master switch is complete with no missing parts??? I found that the grooves in the Tank handle where the throttle trigger rides are worn/wallowed out, which allows a bit of radial movement (wobble) and does not allow the fast Idle position to latch properly and it slides right to the run/idle position, bypassing fast idle...., Here is what I did to make a temp repair until you can find another tank/handle. I took the rear handle cover apart to get the trigger out. I took a small Plastic drinking straw that the ID barely slides over the ends of the metal pin that protrudes on either side of the trigger. I cut two sleeves from the straw that were just long enough to cover the pins and bush the worn slots in the trigger handle (reduces wobble). reassemble and give it a whirl!!! If it is too worn for the drinking straw bushings to work I've taken a big ty-wrap/cable tie and install loosely around the handle, adjust to give you a fast idle. Once she pops on cold choke start, slide the ty-wrap in place crank then blip the throttle and the ty-wrap once you get it adjusted to work for your liking and cut wood.

There's always more than one way to skin a cat

I think the loop around the handle may eventually be necessary. Make-shift, yes, but I'll go with whatever works. This problem is actually occurring with both a new tank handle and the old one. I believe this to be an early production problem that was later fixed by Stihl--maybe two-to three years after the 066 was launched, and my friend has an early release. The mechanism and linkage is so complicated that even a small error can cause it.

The saw also needs a new carb that I ordered. While in transit, I'll play with your other bushing idea and with some other ideas. Note that the trigger only has to move up about 1/8" temporarily to set up the fast idle in both the choke and fast idle switch positions. Somehow a shim inside the handle in the right place may work. If successful, I'll take a couple of Pics. One nice thing is that I can use my 660 as a model to see why it works and the 066 does not. There has to be a subtle difference between them and putting them side-by-side should be helpful.

 

[Wood Doctor]

Well, the good news is I fixed the beast. That's what is was--a beast. Believe it or not, the plastic switch rod was just barely warp bent, back towards the case by about 0.05". That small bend is all it took to disengage the fast idle control setting at either the choke or fast idle position.

To compensate for the bend, I made a small shim part to serve also as a bearing for the left end of the switch rod, embedded right behind it. Then I added some clearance to the filter base where it secures the switch rod. Without this added clearance, the rod's rotation is too stiff. I'll post Pics after I install the new carb. I have to wonder how many saws are out there that do not choke or fast idle correctly (and thus are more difficult to start) simply because of a slightly bent plastic switch rod.

Before making the new part, I tried another switch rod that had no bend, but even it occasionally failed to hold fast idle. So, the fault was not entirely with the switch rod but perhaps also with the tank housing dimensions being off slightly. Conclusion: when you try to make a complicated set of devices like this in mass production, a few may fail. This design is way too complex, kind of like the chain brake mechanism, but that's another story.

 

[whitedogone]

Just had a similar issue with my 066. Took the handle/throttle co tool apart. It had a lot of crap in there. I cleaned it good with purple power, dried it, reassembled, and sprayed it down good with silicone. I will say that you can't really hear it "pop" on choke. Give it 2 or 3 pulls, then try to start off choke.

 

[Wood Doctor]

Just had a similar issue with my 066. Took the handle/throttle co tool apart. It had a lot of crap in there. I cleaned it good with purple power, dried it, reassembled, and sprayed it down good with silicone. I will say that you can't really hear it "pop" on choke. Give it 2 or 3 pulls, then try to start off choke.

I conclude that you were not getting a fast-idle setting on choke. Place the throttle control on choke. The throttle trigger should remain almost closed as if wide open or a bit less--not dropped down. Now move it one click up to Fast Idle. The throttle trigger should barely move. If the trigger drops down, then you have the same trouble that I suspect thousands of 066 owners now experience. That is precisely the problem that I fixed for my friend's 066 today.