Question about sheared flywheel key - Skil 1612

[ClydesdaleClop]

Newbie - working on a Skil 1612 that sat for about a dozen years and first time working on a chainsaw, mentioned it in my introductions post. Took it apart, cleaned it and put it back together. Had to make a new gasket for the fuel/oil tank and also rebuilt carb. Put it back together, got it started on the third pull and ran into two problems. Chain was spinning instantly after it fired and toggling the switch wouldn't shut it off. No injuries or mayhem - I didn't know what to expect so was in a safe position and place when I started it. Thought maybe the switch wasn't working since the saw wasn't at lower speed/idling correctly; I was able to back off the idle adjustment with the screwdriver and the saw cut out suddenly. Couldn't get it to restart after that and then it just was fuel coming out of the muffler. Took it apart partially, checked ignition, no spark. Took it apart today to check rest of it and the flywheel key is sheared off. My question is if the flywheel key sheared because of the stop, did that impact the timing on the ignition and that's why I couldn't restart/get a spark? In addition to figuring out a replacement for flywheel key, if I can find one, just trying to understand if I need to troubleshoot something else in the electrical. Know the idle and carb settings were bad/not correct/unsafe - found the manual online for the original settings and was going to try to use those as starting point to tune if I could get it running again. I was using 40:1 premix; this saw originally called for 16:1.

 

[Old2stroke]

There must be something wrong with the kill switch or wiring, it should kill the ignition regardless of engine speed. Easy to check with an ohm meter, it should short the ignition system to engine case to shut off ignition.
Don't know what sheared the FW key but it isn't really necessary except to accurately located the FW for correct timing, it's the jam fit of the FW on the tapered end of the crank and the proper torqueing of the nut that holds it in place. Easy to make a new one by hacksawing a section of a large washer and filing to fit. I believe that saw has a points/magneto ignition and if the FW location has slipped on the crank, the opening of the points relative to the position of the FW magnets and coil will be wrong and you won't get a spark.

 

[ClydesdaleClop]

Thank you for the reply. Sheared to me means broken off - so flywheel key was in two pieces. Should have just said it broke. Appreciate the information on kill switch and suggestion on washer - I’ll give that a try.

 

[Old2stroke]

Thank you for the reply. Sheared to me means broken off - so flywheel key was in two pieces. Should have just said it broke. Appreciate the information on kill switch and suggestion on washer - I’ll give that a try.

Did the FW come off easily? If it did, the nut probably had not been tight enough. It's important that the tapered surfaces of the FW and the crank are jammed together tight enough. If you do a search on this forum, you can find torque specs for the nut depending on the size of the threaded end of the crank. Important that the nut is as tight as it should be but you DO NOT want to over tighten and strip threads.

 

[ClydesdaleClop]

It came off easier than the first time when I took it apart. I loosened nut until flush with end of crank, held on to the flywheel and gave the nut/end of crankshaft a couple quick raps with a small hammer. That was enough to get the flywheel loose, but it didn’t just slide off. Point noted on the torque - I’ll look around. I will post back when I get a new key made and get a chance to reassemble/test.

 

[Gamma Woods]

Newbie - working on a Skil 1612 that sat for about a dozen years and first time working on a chainsaw, mentioned it in my introductions post. Took it apart, cleaned it and put it back together. Had to make a new gasket for the fuel/oil tank and also rebuilt carb. Put it back together, got it started on the third pull and ran into two problems. Chain was spinning instantly after it fired and toggling the switch wouldn't shut it off. No injuries or mayhem - I didn't know what to expect so was in a safe position and place when I started it. Thought maybe the switch wasn't working since the saw wasn't at lower speed/idling correctly; I was able to back off the idle adjustment with the screwdriver and the saw cut out suddenly. Couldn't get it to restart after that and then it just was fuel coming out of the muffler. Took it apart partially, checked ignition, no spark. Took it apart today to check rest of it and the flywheel key is sheared off. My question is if the flywheel key sheared because of the stop, did that impact the timing on the ignition and that's why I couldn't restart/get a spark? In addition to figuring out a replacement for flywheel key, if I can find one, just trying to understand if I need to troubleshoot something else in the electrical. Know the idle and carb settings were bad/not correct/unsafe - found the manual online for the original settings and was going to try to use those as starting point to tune if I could get it running again. I was using 40:1 premix; this saw originally called for 16:1.

I just want to double check one of the basics, how did you check for spark? If you just ground the plug and watch, try another plug first. Although the whole switch not working at all (running or not) definitely feels like there's a break or grounding somewhere. Did you take the switch/handle apart when you rebuilt it? Or maybe trying to pry the throttle linkage onto the carb knocked something around (don't have this particular model myself, maybe a washer or a bolt is loose and made a connection then jiggled free? A contact plate was warped or mispositioned?).

The flywheel key is helpful to have, but it's not necessary. If you're worried about the timing slipping when you're tightening the nut, you can mark the edge of the flywheel and the edge of the case first (when you know it's set correctly) and keep them lined up as you snug it up.

 

[Gamma Woods]

And I now realize this thread was from January 7th, not February.

 

[farmhard]

Newbie - working on a Skil 1612 that sat for about a dozen years and first time working on a chainsaw, mentioned it in my introductions post. Took it apart, cleaned it and put it back together. Had to make a new gasket for the fuel/oil tank and also rebuilt carb. Put it back together, got it started on the third pull and ran into two problems. Chain was spinning instantly after it fired and toggling the switch wouldn't shut it off. No injuries or mayhem - I didn't know what to expect so was in a safe position and place when I started it. Thought maybe the switch wasn't working since the saw wasn't at lower speed/idling correctly; I was able to back off the idle adjustment with the screwdriver and the saw cut out suddenly. Couldn't get it to restart after that and then it just was fuel coming out of the muffler. Took it apart partially, checked ignition, no spark. Took it apart today to check rest of it and the flywheel key is sheared off. My question is if the flywheel key sheared because of the stop, did that impact the timing on the ignition and that's why I couldn't restart/get a spark? In addition to figuring out a replacement for flywheel key, if I can find one, just trying to understand if I need to troubleshoot something else in the electrical. Know the idle and carb settings were bad/not correct/unsafe - found the manual online for the original settings and was going to try to use those as starting point to tune if I could get it running again. I was using 40:1 premix; this saw originally called for 16:1.

Stop sw will not work if idle is too high, make sure the flywheel and taper is clean, do not use oil. Pull your muffkin and check the rings.

 

[grizz55chev]

Stop sw will not work if idle is too high, make sure the flywheel and taper is clean, do not use oil. Pull your muffkin and check the rings.

Kill switch works no matter the engine speed, it grounds out the coil killing the spark.

 

[farmhard]

Kill switch works no matter the engine speed, it grounds out the coil killing the spark.

I would have to disagree with that. I had several TS360's with the idle speed bumped up too high that wont kill.

 

[grizz55chev]

I would have to disagree with that. I had several TS360's with the idle speed bumped up too high that wont kill.

Disagree away, your particular example indicates a malfunctioning kill switch. Kill the spark , it cannot function.

 

[farmhard]

Disagree away, your particular example indicates a malfunctioning kill switch. Kill the spark , it cannot function.

Cement saws especially get resistance from dirt, J reds with ****** switches melt inside. It's relevant when the OP stated he turned the idle down and it stopped.
I see saws jackep up all the time that won't shut off till I tune them.
He also noted the chain was spinning. Either the clutch was seized or the idle was too high.
He turned it down.
Possible the flywheel nut was loose from the repair or just loose - not accusing but I have done it myself.

 

[farmhard]

I may have 10-15 of those saws here that would be close to running. I was considering parting out but never got around to it.

 

[huskydavid]

Newbie - working on a Skil 1612 that sat for about a dozen years and first time working on a chainsaw, mentioned it in my introductions post. Took it apart, cleaned it and put it back together. Had to make a new gasket for the fuel/oil tank and also rebuilt carb. Put it back together, got it started on the third pull and ran into two problems. Chain was spinning instantly after it fired and toggling the switch wouldn't shut it off. No injuries or mayhem - I didn't know what to expect so was in a safe position and place when I started it. Thought maybe the switch wasn't working since the saw wasn't at lower speed/idling correctly; I was able to back off the idle adjustment with the screwdriver and the saw cut out suddenly. Couldn't get it to restart after that and then it just was fuel coming out of the muffler. Took it apart partially, checked ignition, no spark. Took it apart today to check rest of it and the flywheel key is sheared off. My question is if the flywheel key sheared because of the stop, did that impact the timing on the ignition and that's why I couldn't restart/get a spark? In addition to figuring out a replacement for flywheel key, if I can find one, just trying to understand if I need to troubleshoot something else in the electrical. Know the idle and carb settings were bad/not correct/unsafe - found the manual online for the original settings and was going to try to use those as starting point to tune if I could get it running again. I was using 40:1 premix; this saw originally called for 16:1.

i have a 1612 flywheel if you need one?