Craftsman 3.7 Flywheel/Pawl Question

[Wood Doctor]

I'm working on an elderly Craftsman 3.7 that runs well, but one of the starter pawls broke off and needs replacing. I removed the flywheel and I am not sure if it screws into the flywheel the same way my McCulloch 610 does or if it's a simple press fit pounded in. Here's a Pic of both front and back:
I tried just knocking it out from the back side with a 5/32" rod and all I managed to do was bend the rod (even a short one). That failed, so before I go any further with a 5/32" pin punch a 3-lb sledgehammer, I thought I would ask the forum if this pin is screwed in? If it is, then I see no way of removing it except if I cut a straight slot with a hacksaw and try to unscew it, assuming it is a thread fit. As it stands, the head of the pin cannot be grabbed with any tool I have.

Normally I would order a new flywheel assembly but these parts are no longer available -- a common problem with vintage tools. How should I proceed? TIA.

 

[grizz55chev]

I'm working on an elderly Craftsman 3.7 that runs well, but one of the starter pawls broke off and needs replacing. I removed the flywheel and I am not sure if it screws into the flywheel the same way my McCulloch 610 does or if it's a simple press fit pounded in. Here's a Pic of both front and back:
View attachment 973575I tried just knocking it out from the back side with a 5/32" rod and all I managed to do was bend the rod (even a short one). That failed, so before I go any further with a 5/32" pin punch a 3-lb sledgehammer, I thought I would ask the forum if this pin is screwed in? If it is, then I see no way of removing ot except if I cut a straight slot with a hacksaw and try to unscew it, assuming it is a thread fit. As it stands, the head of the pin cannot be grabbed with any tool I have.

Normally I would order a new flywheel assembly but these parts are no longer available -- a common problem with vintage tools. How should I proceed? TIA.

Find an IPL, or go to the sears parts look up, they have blowup pics of the parts that should help.

 

[67L36Driver]

See if it has ‘Wico’ or ‘Phelon’ printed on it.

Them old devils used a somewhat generic points magneto. Most all mounted on the saw the same way.

That could narrow down the search. Like Wico #xxxxxxx.

Here is one of a like style:

https://www.ebay.com/itm/Jonsered-C...2349624.m46890.l49286&mkrid=711-127632-2357-0

 

[Wood Doctor]

Find an IPL, or go to the sears parts look up, they have blowup pics of the parts that should help.

I tried that. All they show is the flywheel assembled with the pawls and the pins are not shown as a separate part. One has to wonder how it was put together in the first place.

 

[HarleyT]

Take a drill and drill out those pilot holes, then tap them out with a pin punch.

 

[Wood Doctor]

See if it has ‘Wico’ or ‘Phelon’ printed on it.

Them old devils used a somewhat generic points magneto. Most all mounted on the saw the same way.

That could narrow down the search. Like Wico #xxxxxxx.

Here is one of a like style:

https://www.ebay.com/itm/Jonsered-C...2349624.m46890.l49286&mkrid=711-127632-2357-0

Phelon is engraved on the fin side. Here's one that looks like a dead ringer:

Phelon Chainsaw 12407-02 7105 Flywheel​

Oops! not really. Fewer fins and likely smaller diameter.

 

[grizz55chev]

Take a drill and drill out those pilot holes, then tap them out with a pin punch.

Maybe a little heat to loosen things up?

 

[Wood Doctor]

Take a drill and drill out those pilot holes, then tap them out with a pin punch.

So, Harley, you think these are threaded fasteners? If so, I may try the hacksaw slot first, assuming it's not casehardened steel. If it is, the drill out won't work either. I tend to think they are threaded and that's why they refused to break loose.

 

[HarleyT]

No, I mean just drill out the little bit of aluminum, to expose the pins. I doubt that they are threaded, if there is no way to tighten/unscrew.

 

[Wood Doctor]

No, I mean just drill out the little bit of aluminum, to expose the pins. I doubt that they are threaded, if there is no way to tighten/unscrew.

That's worth a try because it is possible that hole shown in the back view does not extend to the pin and that is why I could not drive it out. I'll, try a 5/32" bit first and see what happens. Moved up to 11/64" bit and that did reveal a gap between the casting and the end of the pin. I'll dump in some penetrating oil and wait a little.

 

[Old2stroke]

Pretty sure they are pressed in and not considered to be a serviceable item, that's why they aren't listed as separate parts. Penetrating oil won't help with pressed together things but high heat will, you want to get it out without a lot of damage as you will want to press it back together. Do you have a replacement pawl?

 

[Wood Doctor]

Pretty sure they are pressed in and not considered to be a serviceable item, that's why they aren't listed as separate parts. Penetrating oil won't help with pressed together things but high heat will, you want to get it out without a lot of damage as you will want to press it back together. Do you have a replacement pawl?

Yes I do have a replacement pawl that should work. It looks identical to the remaining good pawl. Heat is about the only thing I have not tried. WD-40 was no better than Liquid Wrench. I imagine when these flywheels were built they used tons of force to seal the pins in. I imagine that using a pin punch won't remove it either. If I hit it any harder than I already have with the hammer I will wreck the punch. I've tried both a 3-lb sledge and a ball peeen with many hits. It's still locked in tight as a drum.

I also hate to drill out the pin to remove it. That would mean threading the hole and trying to replace the pin with a machine screw and thread adhesive. Not impossible, (unless the pin is case hardened) but that would be a last resort because to my knowledge there are no replacement flywheels available for this engine.

 

[HarleyT]

What surface are you setting the flywheel on?

 

[Wood Doctor]

What surface are you setting the flywheel on?

Solid oak laminated bench top, about 2.5" thick, right over a support leg. The remaining good pawl nests inside a 3/4" diameter hole for clearance so that the flywheel remains dead flat with no pressure on the pawl. This bench top is rock solid with no give. It might even be less resilient than a concrete floor with 3/8" thick hardwood strips to protect the good pawl. I suppose I could try that.

 

[HarleyT]

When looking at the inward side of the flywheel, do you see steel pin or aluminum when you look in those holes?

 

[Wood Doctor]

Harley asked, "When looking at the inward side of the flywheel, do you see steel pin or aluminum when you look in those holes?"
------------------------------
Ans. Steel. I believe that's the end of the pin (bold type in post #10). I drilled out the casting and encountered an air gap of about 1/8" as the drill bit made it through the casting and then struck the pin. At that point, I stopped drilling with the 11/64" bit. I believe I am now pounding on the pin rather than the casting as I try to dislodge it with the hammer and pin punch. It's really hard to believe that the pin has not dislodged.

How on earth did Phelon make that friction, pressed-fit joint between an aluminum alloy casting and a steel pin that tight? Rather incredible in my book.

 

[Captain Bruce]

I'm working on an elderly Craftsman 3.7 that runs well, but one of the starter pawls broke off and needs replacing. I removed the flywheel and I am not sure if it screws into the flywheel the same way my McCulloch 610 does or if it's a simple press fit pounded in. Here's a Pic of both front and back:
View attachment 973575I tried just knocking it out from the back side with a 5/32" rod and all I managed to do was bend the rod (even a short one). That failed, so before I go any further with a 5/32" pin punch a 3-lb sledgehammer, I thought I would ask the forum if this pin is screwed in? If it is, then I see no way of removing it except if I cut a straight slot with a hacksaw and try to unscew it, assuming it is a thread fit. As it stands, the head of the pin cannot be grabbed with any tool I have.

Normally I would order a new flywheel assembly but these parts are no longer available -- a common problem with vintage tools. How should I proceed? TIA.

The pins are pressed in. Try and find another flywheel......Craftsman machines are considered dixie cup saws in Michigan/S.W Ontario. Try eBay. You'll buy a basket case, scavenge the flywheel, and toss the rest....

 

[grizz55chev]

The pins are pressed in. Try and find another flywheel......Craftsman machines are considered dixie cup saws in Michigan/S.W Ontario. Try eBay. You'll buy a basket case, scavenge the flywheel, and toss the rest....

They're available, around $15 delivered.

 

[HarleyT]

Put the flywheel on a good hard surface like a bench vice, anvil, or cinder block, and use the correct size pin punch.

 

[Oletrapper]

Yes I do have a replacement pawl that should work. It looks identical to the remaining good pawl. Heat is about the only thing I have not tried. WD-40 was no better than Liquid Wrench. I imagine when these flywheels were built they used tons of force to seal the pins in. I imagine that using a pin punch won't remove it either. If I hit it any harder than I already have with the hammer I will wreck the punch. I've tried both a 3-lb sledge and a ball peeen with many hits. It's still locked in tight as a drum.

I also hate to drill out the pin to remove it. That would mean threading the hole and trying to replace the pin with a machine screw and thread adhesive. Not impossible, (unless the pin is case hardened) but that would be a last resort because to my knowledge there are no replacement flywheels available for this engine.

They are definitely pressed in. As Harley suggested, you need to get it on a very solid steel surface. Also, drilling and tapping I don't believe will work as you will find that the pin has a shoulder that the pawl pivots on and allows room for the spring. It would be hard to find a threaded bolt/screw with the necessary shoulder. I would not heat it as that will probably destroy the spring. Perhaps you know of someone with a machine shop and a hydraulic press? The vertical type that work with a hydraulic jack? Man put it together. Man can get it apart. lol jmho OT