I'm certain a slasher with a PT won't need 3 kg as you have the spinning weight of the blade plate and shaft / pulley with a slasher Norm.
I would say the 3 kg is correct for the PT TAC even though I've never looked at one in person ,in the parts diagram it looks the same as the 3 kg pulley from eBay.
The reason the edger needs 3 kg is because there is very little spinning mass without the 3 kg ( just a small flat blade on a shaft with bearings and pulley.) Also more mass helps the motor keep it's rpm without stalling under load. Disadvantage of a heavy flywheel is the rotational speed of the engine does not rapidly increase even when the throttle is opened quickly ,not a concern for an edger.
We know the full crank will need less weight than the PT and the restrictor on the decomp valve is worth doing so you don't have to add too much weight.
Also we know all the Briggs ride on mower engines that have a sheet metal pulley on the end of the crank use a heavy cast iron flywheel.
I have a couple of non Victa edgers here but never looked at them ,I would guess they have heavy flywheels ,I can always check them.
I'm just back from a trip to Eden. I had a look at the PT converted 24 that I did 3 yrs ago. It's a first pull starter now. No kick at all. Brother is convinced it's the spring tension in the decompressor. I wonder if we could load up the spring with some spacers or something. Amazing that there is so many heavy pulley and flywheel options for the PT.
The 24 has cut a half acre block of Kikuyu for 3 yrs.A beautiful lawn now.
I left him with a problem in his Briggs powered mulcher. Starts OK then slowly dies as it heat s up. Seems to be spark as an online timing light goes OFf as it heats up. I suggested having a good look at the stopper circuit.maybe disconnect to see if it has any effect. Other than that, coil?, module?
Hi Jeff, I really wish I knew the secret to the one you built, it has me thinking all the time as to why it works so well. Really happy for your brother that it is doing such a good job. I can't believe it is 3 years since you built it. As for the Briggs I'm thinking coil going off.
Hi Max, I always thought the spinning weight of the blade carrier would have been more than sufficient but it obviously the belt does not transfer the weight well enough for that brief instant that the piston hits TDC and the belt can flex enough to allow it to kick back. At least we now have the answer to the problem. Hi Jeff, the decomp is an important component in these belt driven machines, far more critical than a mower with the blade carrier bolted directly to the crank. I tried several mods to decomp valves to try and slow down the way it closed so that the motor could get some speed up to get over TDC. The proof of this was with this Tilt A Cut, even though I had a kg added to the crank it was still impossible to start without severe kickback. The only thing I can put this down to is the diameter of the spinning weight, maybe this makes a difference but remember this is a F/C motor so it already has a heavier crank. With the restricted decomp it starts easily. My next thing will be to remove the weight off the crank and see what happens. The other thing that confuses me a bit with the decomps is that I had a motor where the decomp valve itself was just floating in the head (they can't drop in on top of the piston because of the head design) but that motor started easily and ran fine. Obviously as the piston came up on compression it was able to push the valve shut. All very technical and a real balancing act to get them right when they decide to give issues.
