Chainsaw Repair

Some old 064 066 info I remember reading.

Just 2nd hand info and dont know how accurate it is.

There is a lot of confusion over the 066 'red eye' or 'red light' model saws. Also a lot of confused between the Red Light 066 and the similar limited non red light 064. Even in what has been posted here. You can run an early model 066 red light with the aluminum flywheel with one of the later aluminum flywheel unlimited coils. All the US 066 AL flywheel models should only have one key in the flywheel. I had an AL flywheel on my Red Light 066, and I still have the later Iida coil model from it. It ran fine. The limited coils were commonly pulled and replaced with unlimited ones to run better. This was because the red light coil module would fade out over time and limit downward on RPM's (like 12.5k down to 10k RPM). The non-limiting coils do not have the extra wire and LED lead though. Some 066 red lights were Magnums (mine was), meaning they had the dual port muffler for increasing the 7.3 HP 'regular' 066 to 7.8 HP.

I have the Stihl 066/064 factory ignition module tech sheet that lists the 6 most common aluminum and poly flywheels (there are a whole series of them) as well as all the matched coils. However, there were 9 options in all. There were at least two later models of AL flywheels on non-red-eye 066 before they flipped to polymer in 1996. The red light 066 was only made for a short period of time. They were only made on a very early flat top 066; there was no later model 066 using them. There was an RPM rev limiter in the coil and an LED lead running from the coil to an LED light at the side of the saw. The light lit up when the rev limit was reached and the coil was cutting out. This was so that you could tune the carb H screw to lean it out just until it was cutting out, and the LED light was flashing. For that reason these saws had engines that were fairly bullet-proof; it was nearly impossible to score the engine with the limiter in them. Only straight gassing did them in. Or the bearings went out, as was the case with mine. The swapped out red light and later models of 066 with the AL flywheel and unlimited coil had a common problem with spinning the flywheel side of the crankshaft off because of over revving. So Stihl made the flywheel side of the crank thicker in 1996 and replaced the aluminum with a poly flywheel. They also changed the ignition modules to to advance the timing at high revs on the later poly coils. The AL flywheel coils are straight-line timed ignitions; they do not have an advance curve in them like the poly modules do. The CDIC coils also had a timing retard in them at low speed for easier starting.

In the above post, the 1303 module was in the 064, and not the 066. The red light 066 coil module was a Prufrex CDIC, Stihl PN: 1122 400 1307 (similar to the 064 module, but it has the LED lead). It was changed to an Iida unlimited coil module, Stihl PN: 0000 400 1300, in 1993 and retained the AL flywheel. That was changed to an Iida unlimited coil module, Stihl PN: 1122 400 1311, in 1994. The 0000 400 1300 coil is a generic coil and is still used in some of the new larger Stihl saws. The 064 also had a CDIC coil put in them from 1989, but there was no red light limiter LED. Note that only the 064 AL flywheels have two key slots. This is to accomodate different types of ignition; one was for electronic ignition, and the other was for analog points and condenser ignitions. On these flywheels, B stands for Bosche (old points) and P stands for Prufrex (new electronic).