STIHL MS 066 REPAIR HELP ME OUT

[Cooper264]

Im working on an 066 for a friend and I told him I could have it running in under 2 hours....

I WAS WRONG

It had a fuel tank that the two halves had seperated, he tried to repair them but the gas ate whatever he used so they were pretty bad off. I wasn't really in the mood to plasti weld them so I replaced the fuel tank with one of the FT 660 tanks.

There were a few wires messed up on the original tank so that kinda helped in my decision to replace it. When i did the tank, I replaced 3 of the av buffers, the stihl ones were either dry rotted or worn slap out.
I took the jug off and cleaned off some exhaust residue, replaced the exhaust and cylinder gasket. Bearings and oil seals looked pretty good. The OEM stihl cylinder and piston looked extremely good for the age of the saw and the fact that 3 of the buffers were trashed.

Replaced the coil with a FT 660 coil, replaced the walbro carb with an old FT I had laying around, replaced plug with a FT.

on top of the mechanical stuff, I replaced chain tensioner and chain break junk with FT, I would have left it all stihl but a few parts were missing..

So I started cranking on the saw, It popped one time. Not like a normal start where it fires once on choke and then runs off choke. All it did was pop. Nothing more. Didnt get a sputter, spit, spat, nothin.

I know it is definitly getting fire and fuel.. It was flooded when I took the plug out. I drained it and tried it with the old carb, I doubted the FT because it was kinda old and slightly used. Instantly flooded

My main question is about the coil and flywheel. I havn't checked the flywheel nut yet, i know thats a pretty good reason for it just straight flooding itself.
But does the original OEM flywheel work differently with a FT coil than it does the OEM coil??
Do I need to switch it over to a FT flywheel?

Any help would be greatly appreciated.

 

[huskyboy]

Some friendly advice... rebuild the oem carb, aftermarket carbs are usually junk. Also was the saw a red light saw? They used a different coil and flywheel combo than the later unlimited 066/660. The farmertec flywheel will only work if the saw has the poly flywheel and big crank stub. It won’t work on a metal flywheel crank saw, the stub is smaller. Some pictures of the flywheel and coil would be helpful to help us help you...

 

[BuckthornBonnie]

Aftermarket coils have high failure rates. I used to buy them just for the plug wire and spare wiring.

Rebuild with OEM as said above. The tank itself is probably fine.

 

[angelo c]

why did you replace the coul and Fw in the first place?
also i agree wit Mason...rebuild the oem carby before trying a farmertec carby.
was the saw running before the "repairs" ?

 

[Cooper264]

Some friendly advice... rebuild the oem carb, aftermarket carbs are usually junk. Also was the saw a red light saw? They used a different coil and flywheel combo than the later unlimited 066/660. The farmertec flywheel will only work if the saw has the poly flywheel and big crank stub. It won’t work on a metal flywheel crank saw, the stub is smaller. Some pictures of the flywheel and coil would be helpful to help us help you...

why did you replace the coul and Fw in the first place?
also i agree wit Mason...rebuild the oem carby before trying a farmertec carby.
was the saw running before the "repairs" ?

This saw did have the red light thing on it. I don't know enough about the 066's to know what it was or how it worked...
This ole gal was not running befor I got ahold of it. It had been sitting in a garage for many years and had some parts robbed off of it.

I changed the coil because of the tank change. The saw wasn't getting spark before i yanked the handle/tank off and the FT 660 tank doesn't have a hole for the red light thing. I could have drilled a hole in the FT handle and added the light, that would have been pretty bad ass. But I wasn't thinking everything through. On top of the light, the wires had a few stripped places that I figured were giving it issues.

So for me it was easier just to slap on a FT coil than repair the OEM one.


That being said, would it be worth redoing the wires and drilling a hole in the side of the new handle assembly for the old OEM coil and red light? or is it more likely that the reason it wasn't getting spark was that the coil is bad.

Also, what would I have to do to get a FT coil on it if i can't get the OEM coil back up and running

 

[Cooper264]

On a side note, Does anyone want to buy a half rebuilt/torn apart 066 red light? lol
For some reason I feel like this is more complicated than I was bargaining for

 

[Wood Doctor]

Im working on an 066 for a friend and I told him I could have it running in under 2 hours....

I WAS WRONG

It had a fuel tank that the two halves had seperated, he tried to repair them but the gas ate whatever he used so they were pretty bad off. I wasn't really in the mood to plasti weld them so I replaced the fuel tank with one of the FT 660 tanks.

There were a few wires messed up on the original tank so that kinda helped in my decision to replace it. When i did the tank, I replaced 3 of the av buffers, the stihl ones were either dry rotted or worn slap out.
I took the jug off and cleaned off some exhaust residue, replaced the exhaust and cylinder gasket. Bearings and oil seals looked pretty good. The OEM stihl cylinder and piston looked extremely good for the age of the saw and the fact that 3 of the buffers were trashed.

Replaced the coil with a FT 660 coil, replaced the walbro carb with an old FT I had laying around, replaced plug with a FT.

on top of the mechanical stuff, I replaced chain tensioner and chain break junk with FT, I would have left it all stihl but a few parts were missing..

So I started cranking on the saw, It popped one time. Not like a normal start where it fires once on choke and then runs off choke. All it did was pop. Nothing more. Didnt get a sputter, spit, spat, nothin.

I know it is definitly getting fire and fuel.. It was flooded when I took the plug out. I drained it and tried it with the old carb, I doubted the FT because it was kinda old and slightly used. Instantly flooded

My main question is about the coil and flywheel. I havn't checked the flywheel nut yet, i know thats a pretty good reason for it just straight flooding itself.
But does the original OEM flywheel work differently with a FT coil than it does the OEM coil??
Do I need to switch it over to a FT flywheel?

Any help would be greatly appreciated.

You are not getting a fast idle. It's a common problem with the 066, 650 and 660. It will pop on choke and then when you move the switch shaft to fast idle, it drops to idle in the Run position. When cold, it will not start there and do exactly what you ran into. It needs a Fast Idle.

Some guys get them running by holding the throttle at WOT and then pulling a few times there, but that means you need three arms or hands if you are drop starting it. So, it has to go on the ground or on a support, like a 5 gallon bucket upside down. Even that usually means switching over and holding the throttle open with you left hand while the right hand pulls (assuming you are right handed) and your knee holds the saw down. It's awkward to say the least.

This is a design flaw that faces about 90% of all these saws and Stihl never released a remedy. Instead, they proceeded to build the MS661. What I did was design a shim that fits on the back left side of the switch shaft and pushes the left side out so that it will hold the fast idle position:

Try stuffing in there a a plastic wedge-shaped piece like a plastic screw anchor. That works also. The filter base will help hold it in place.

 

[Nutball]

My FT saw has a super touchy switch. It will readily go to the idle position if it doesn't jump to off. Just touch it and it will turn off. I didn't put a shim in mine because I didn't know that it held it firmer in the position notches.

 

[Ksaws]

You can't replace a limited coil with an unlimited one. Flywheel key position is different.

You'll have to cut a new keyway in the appropriate position or get an unlimited flywheel. There's a thread here somewhere that lists all the combinations of flywheels and coils.

FT carbs are crap. Coils do work sometimes.

 

[Maintenance Chief]

Pictures would be great

 

[drf256]

Do yourself a favor. Put as much oem stuff back on that saw, repaired, as possible. Then retry.

Are you sure your oem coil was bad? Are you sure it wasn’t the stripped wires in the tank shorting out? You can use the FT wires and tank. Make sure you take as much oem stuff off and put it back on from old tank, like carb box, trigger, operator lever. Also the brake handle, brake parts. Use the FT only for what’s missing.

Also, throw the FT plug in the garbage and put a new quality plug in the cylinder.

 

[BuckthornBonnie]

Yes

On a side note, Does anyone want to buy a half rebuilt/torn apart 066 red light? lol
For some reason I feel like this is more complicated than I was bargaining for

 

[stihl_head1982]

Do yourself a favor. Put as much oem stuff back on that saw, repaired, as possible. Then retry.

Are you sure your oem coil was bad? Are you sure it wasn’t the stripped wires in the tank shorting out? You can use the FT wires and tank. Make sure you take as much oem stuff off and put it back on from old tank, like carb box, trigger, operator lever. Also the brake handle, brake parts. Use the FT only for what’s missing.

Also, throw the FT plug in the garbage and put a new quality plug in the cylinder.

+1 for me.

 

[67L36Driver]

A loose zip tie around the throttle trigger/handle can bypass a malfunctioning fast idle latch. [emoji106]

The Chinese coils lack the delayed advance feature that OE MS460 & MS660 have.

 

[Wood Doctor]

A loose zip tie around the throttle trigger/handle can bypass a malfunctioning fast idle latch. [emoji106]

The Chinese coils lack the delayed advance feature that OE MS460 & MS660 have.

A loose zip tie is the other solution alternative to post #7. I've worked on over a dozen MS660's with these loose throttle loops. Loggers did not like them but at least it was better than nothing. What amazes me is that Stihl never admitted that there ever was a problem and never sent out a factory recall. Pull cords and pull handles wore out left and right because of thousands of useless starting pulls.

 

[Cooper264]

You are not getting a fast idle. It's a common problem with the 066, 650 and 660. It will pop on choke and then when you move the switch shaft to fast idle, it drops to idle in the Run position. When cold, it will not start there and do exactly what you ran into. It needs a Fast Idle.

Some guys get them running by holding the throttle at WOT and then pulling a few times there, but that means you need three arms or hands if you are drop starting it. So, it has to go on the ground or on a support, like a 5 gallon bucket upside down. Even that usually means switching over and holding the throttle open with you left hand while the right hand pulls (assuming you are right handed) and your knee holds the saw down. It's awkward to say the least.

This is a design flaw that faces about 90% of all these saws and Stihl never released a remedy. Instead, they proceeded to build the MS661. What I did was design a shim that fits on the back left side of the switch shaft and pushes the left side out so that it will hold the fast idle position:
View attachment 279670
Try stuffing in there a a plastic wedge-shaped piece like a plastic screw anchor. That works also. The filter base will help hold it in place.

I have deffinitly had this problem alot, with the FT kits. I have figured out that if you shim the trigger piece just a hair and lube up the choke sidde of the carb it works alot better. That little bit of friction on the choke flap keeps the high idle lever from sticking down and catching the throttle lever properly in my experience

 

[Cooper264]

Do yourself a favor. Put as much oem stuff back on that saw, repaired, as possible. Then retry.

Are you sure your oem coil was bad? Are you sure it wasn’t the stripped wires in the tank shorting out? You can use the FT wires and tank. Make sure you take as much oem stuff off and put it back on from old tank, like carb box, trigger, operator lever. Also the brake handle, brake parts. Use the FT only for what’s missing.

Also, throw the FT plug in the garbage and put a new quality plug in the cylinder.

Where it is a red light saw, it has the 3 wires coming out of the OEM coil, Can I just use two of the wire slots or will I have to do some rigging to get er to work with just the 2 wires that the FT comes with?

 

[huskyboy]

Where it is a red light saw, it has the 3 wires coming out of the OEM coil, Can I just use two of the wire slots or will I have to do some rigging to get er to work with just the 2 wires that the FT comes with?

The limited flywheel will not work with the aftermarket unlimited coil as a straight bolt on.

 

[Ksaws]

Where it is a red light saw, it has the 3 wires coming out of the OEM coil, Can I just use two of the wire slots or will I have to do some rigging to get er to work with just the 2 wires that the FT comes with?

Should just work with the 2 wires.

 

[Ksaws]

On a side note, Does anyone want to buy a half rebuilt/torn apart 066 red light? lol
For some reason I feel like this is more complicated than I was bargaining for

Several here will want it if you'd rather be quit of it...