Husqvarna 272/Jonsered 670 Repair Thread

[Onan18]

Like with the 50/51/55 thread, this thread will document the repairs saws from this chassis. This platform has been long lived and some great saws were built on it. There were the Husqvarna 162/61/66/266/268/ and 272. On the Jonsered side there was the 625/630/ and 670. @afleetcommand and @Spike60 did a great info video on this topic, a "Saw College" that I will link. Anyone with any info to contribute please do so.

 

[Onan18]

In for a rebuild is a Husqvarna 266. Local Tree Guy bought it at a pawn shop and it didn't run right, landed on my bench and the piston was scored. He elected to have it rebuilt, will be going back together as a 52mm 272 XP as that is the only cylinder still available for this chassis apart from the 48mm open port 61 cylinder.


Didn't think to get any pictures before it was this far apart.

There are a few changes that need to be made to run a 272 cylinder on a 266, I will go over those as we get to them.

 

[Onan18]

From where we were lets start by removing the throttle linkage. It just snaps into the plastic arm, use a screwdriver to pop it out and then twist and the other end will come out of the carb.


On these older saws the front handle was held on with 8mm socket head screws.

Get the handle out of the way.


Clutch comes off with a 19mm socket, left hand threads.

 

[Onan18]

The oil pump has a plastic shield washer to help keep debris out of the worm gear.


Take off the washer and spin the worm out. There is a steel spacer hiding under the worm.


A 3mm Allen key to remove the oil pump screws.


And the pump lifts out.


There is a thin o ring that seals the pump to the case, it is good practice to replace it every time the pump is off.

 

[Onan18]

This is an older 266, it has the coarse threads for the clutch. Later saws have a more traditional fine thread.


This pump has seen better days, still functions but I will advise the owner that it will be a good idea to replace it.


At the tip of the screwdriver is a small X Ring, this seals the output of the pump to the oil channel in the bar pad.


Oil hose and X Ring removed.

 

[Onan18]

Remove the six A/V screws, 4mm Allen key.


Disconnect the fuel line and the tank comes right off.


Has a couple of broken A/V mounts, will be getting all new ones.

 

[Onan18]

A ball end 4mm Allen is the best way to get the carb bolts out.


Disconnect the choke lever.


And the carb lifts out.


Notice how the 266 intake block bolts to the cylinder, more on that later.

 

[Onan18]

Cylinder bolts for this chassis are an odd size.


Crack them in a X pattern.


And off, shame, full circle big window 266 piston.


Cylinder is ugly as well.

 

[Onan18]

Pair of side cutters works well for removing the flywheel key.


The older two piece ignition saws have a seal holder on the flywheel side.


Off with you!


Small screwdriver is my weapon of choice for removing piston pin clips.


Piston off.

 

[Onan18]

Seven case bolts.


Don't forget the one at the back.


And the dog bolts are case bolts as well.


Three different length case bolts, don't mix them up!

 

[Onan18]

Time to split.


Halfway there.


Crank out.


Be sure to scrape all of the old gasket off.


And thoroughly clean the cases.

 

[Onan18]

I will be getting a crank tool from @Mattyo but until then...


Heat the bearing pocket up, how hot you ask?


Hot enough for the bearing to fall out.


New parts.

 

[Onan18]

I place the bearing on my index finger.


And while the case is still NASA hot drop it in.


Try to get the new bearings exactly where the old ones were.


Both sides done.

 

[Onan18]

Put a little heat in the race.


And the crank will drop in.


Lay the new case gaskets on the locating pins.

A little bit of heat in the other bearing and it slides together, run your screws back in.


Together.

 

[Mattyo]

Oh u r gonna love the tools ....when I get them of course

 

[Onan18]

Oh u r gonna love the tools ....when I get them of course

Thanks Matt, this way works but it can be a little fidgety.

 

[Onan18]

A few of the hard parts after a bath.


Put the X Ring on this pin, it is the output.


Drop the oil hose back in.


The new seal taps in from the back.

 

[dustinwilt68]

Looking good joe, I enjoyed and learned a lot from that video, may have to watch it again, spike has always been a wealth of knowledge when I needed help.

 

[Mattyo]

That's the problem with heat on the bearings....the bearing is now blue....which means it's lost its temper. Same problem happens when u use a grinder on chainsaw chains...

 

[Onan18]

Pry the old o ring off.


An appropriate size socket...


And out.