Pioneer P-50 rebuild?

[troutfisher]

If you are referring to the P26's, first pull off the recoil and check the decompressor. There is a spring on it that keeps the valve closed for normal operating conditions. With the recoil off you should be able to push the valve open with your finger and it should spring back closed when you release it. There should also be a washer on the end that's about 3/4 inch in diameter that holds the spring. Sometimes that washer comes off and the spring comes off or can't keep the valve closed without that washer. New valves are no longer available, so your only choice is to fix it yourself or find a used one. The recoil has a little lever inside that is attached to a gear. When you pull on the rope the gear is pushed inward to engage the flywheel, at the same time the lever pushes open the decompressor valve. When you release the starter rope everything goes back, and the decompressor valve closes.

I have 4 P-26's , so I may be able to use parts. I had no idea how the "easy arc" thing worked, thanks for the info! It'd be nice to hear the old saws run again.

 

[pioneerman]

Hopefully a picture of 2 valves, one on left is new, one on right is used and missing the washer and spring. Not all valves had the split sleeve covering the spring as the one on left has. Probably a new upgrade.

 

[troutfisher]

Hopefully a picture of 2 valves, one on left is new, one on right is used and missing the washer and spring. Not all valves had the split sleeve covering the spring as the one on left has. Probably a new upgrade.

Good info, Thanks. I'll have to get one of those saws apart and check it out.

 

[troutfisher]

You are the Pioneer man! I simply removed the wire that makes the valve work. Saw runs great! Thank you! The saw belongs to my father, and it has lots a sentimental value. It's the first saw I ever used. The other three are parts saws we collected. Thank you!

 

[ross01]

Thanks for all the help. The piston doesn't look too bad but if I could get one I would like to get one. I think that the cylinder is in good shape, the are some marks but they aren't very deep.

You sell all this stuff pest? How much will this cost me?

 

[ross01]

Anyone know where I can find these parts? I called a few shops in the area, but no luck so far.

 

[PES+]

If you could find someone with a digital cam and send me a pic I did find a box full of my reed engine pistons.

The other way is for you to get a caliper and give me all pertinent dimensions. Total height, pin diameter, pin top to piston crown. Where the ring stop pins are located, etc. We can start with the diameter.

It should be 52 MM

 

[ross01]

Ok I got some measurements of the piston. Sorry they are in inches,

Piston diameter - 2.57 inches
Total height - 1.63 inches
Pin diameter - .5 inches
Pin top to piston crown - .7 inches

Do you think that I could just get away with putting some new rings on the old piston?

 

[pioneerman]

What do you expect to pay for an original piston, rings and piston pin. I occassionaly visit a stihl dealer who has an assortment of old pioneer parts and might have some P50 parts still. I paid around $100 for a piston and pin for the Poulan 525 which is the updated version of the original P50. I'm sure that if he has a piston I might be able to get a better deal. If you can get one locally you would be better off, but if you end up stuck I might be able to find one here in Canada.