046 rebuild

[crowe]

Hello guys,

I have an 046 mag that I have cut roughly over a million feet with. I have noticed it starting to fall off a little power wise. I am getting ready to rebuild it, the cylinder walls look good inside. Could I get by with a new set of rings or should I replace all of it.

 

[sedanman]

Remove the muffler and look at the rings while rocking the flywheel a little. How much do the rings "walk" in their grooves? Very little....new rings, somewhat more than a little....new piston, a whole bunch....put a top end on it. Compare ring movement to a new saw if possible to get a reference.

 

[stihltech]

046

Get the jug off and check ALL the bearings. Cagegs must be intact and no cracks or play in the crank. I find a pisto with much over .004 will start to spit back a lot of fuel. If it looks nice and shiny with no machine marks on the skirt, it may be time for a piston.
Remember that anything that comes apart in the bottom end comes UP the the ports to get out. Bigger pieces cause big damage.

 

[rbtree]

Can you get a "B" piston for the 046? It is slightly oversize, and recommended for using witha used cylinder.

 

[stihltech]

046

Now you have been around a while. I haven't seen a B piston in a long time. I think since 045's. I think they decided it was either within spec or it wasn't.
Trick we still use. put finger over sparkplug hole and slide piston in until skirt is even with cylinder bolt flange ( holding cylinder upside down fof course). Let piston drop into cylinder. A good piston will fall very slowly down the bore, a worn one drops down pretty fast. Not very scientific, but it works.

 

[JimL]

Old fart that I work with has some old B pistons layin around. Never knew what they were until now

 

[TheTreeSpyder]

your just not as olde as Rog!

 

[rbtree]

Spidey:

Hey!!! Old is a state of mind...

Stihltech,

thanks... I recently got a chainsaw service manual. It must have old info in it, as it talks about B pistons on several newer models.

 

[stihltech]

046

Which ones? I would like to check it out.