Husqvarna 61 rings seized

[zandrew77]

I have Husqvarna 61 I am converting to 272. I am confused why the piston got hot. It's on the carb side, not the exhaust side. Piston is totally shot but I do not want it too do the same to the new setup. Where should I be looking for issues at; typical crank seals etc?

 

[J D]

Pic's will help with a diagnosis... if you don't know the saws history replacing seals is cheap insurance. Most important thing is to do a vac & pressure test when its back together

 

[singinwoodwackr]

So, this is a 61 case with a 272 top end? yea, pics will help.
I'm planning on doing the same with a spare 61 carcass I have.

 

[Czed]

Replace seals and the oring on the oil pump
You'll see it when you disassemble it.

 

[Cantdog]

Replace seals and the oring on the oil pump
You'll see it when you disassemble it.

And don't forget the same o-ring in the seal carrier under the flywheel if it is the two piece ign or in the case if it is the later one piece ign.

Not usual for a piston to be badly scored on the intake side and fine on the exhaust side???

 

[NSEric]

I dont do vac and pressure test on old saws that are easy to get parts for, I save a bunch of time by skipping that step and put new seals in it.
I coat the O rings on the oil pump and seal holder with motoseal when working on the 2 series huskys.

Check the air filter for a hole or leak, dirt will chew up the intake side of the piston.

 

[zandrew77]

I'll try to get a picture but it's a 61 I am converting to 272. The 61 is smoked on intake but fine on exhaust which is really weird to me.

 

[Agrarian]

You only mention the piston. Does the cylinder have scoring and/or aluminum transfer on the carb side too?
Was the air circulation around the cylinder fins on the carb side severely restricted?

 

[Gord404]

I agree on the seals, a must on old saws anyway but the carb block could have been leaking as well even though you won' be using either on a 372 setup, carb won't put out enough for the larger setup and will have a differnt block- bit of a pita but worth it in the end

 

[Bob Hedgecutter]

I have Husqvarna 61 I am converting to 272. I am confused why the piston got hot. It's on the carb side, not the exhaust side. Piston is totally shot but I do not want it too do the same to the new setup. Where should I be looking for issues at; typical crank seals etc?

Put photos up of said piston so we can guess further- air leaks seldom (if ever) take out the intake side of the piston without also the exhaust. Lean fuel mix (straight gas) is usually a wrap around effect.
Debris however, it can be pretty isolated to point of entry and points of contact.
Could be your seals are still fine but a damaged air filter is letting chunks through the intake causing your damage- or a bearing/cage has let go and gone down the intake side to kill the saw.
Photos of the scoring damage can help establish what type of suspects to look for.

 

[zandrew77]

This should help. I would use terms to describe said piston that most likely would result in a ban from forum. The intake side is totally destroyed. The exist side has minor striations but nothing horrible. The saw itself looks very clean like hardly used.

 

[zandrew77]

Oh and that first picture shows about a 20 thou ledge. Oddly the saw was still making 90psi on comp test.

 

[singinwoodwackr]

Well, the piston is certainly toast,
can’t see much in the cyl pics

 

[Bob Hedgecutter]

How about a stand alone photo shoot of the naked piston- not a cheeky skirt lift to give a partial reveal of what is to come later!
Certainly does not look lean condition scoring to me- but would be good to see the ring and ring groove lands etc and then the exhaust side to compare.

 

[J D]

If that's 0.020" of wear then that pistons been rockin around awfully loose in that cylinder... wrong size piston/ cylinder combination? Bad bearings causing it to come up & down unevenly?

 

[zandrew77]

I'll try to get better pictures later but surprisingly the ring land is intact, and the ring doesn't look like it had straight gas. It's kind of insane.

I never ran this saw, it was traded to me for a poulan bar n chain.

 

[Bob Hedgecutter]

Sounds like the guy that got the bar and chain got the better half of the deal.

 

[NSEric]

I agree on the seals, a must on old saws anyway but the carb block could have been leaking as well even though you won' be using either on a 372 setup, carb won't put out enough for the larger setup and will have a differnt block- bit of a pita but worth it in the end

This isnt right at all.
You can add the 272 cylinder to a 61 with the 61's intake/carb/carb holder just fine. On the older ones all you need the 272 intake bolts, they're 4mm not 5mm.
On the newer orange top ones, everything is the same for a 61, 268 or 272 on the intake so all you need is a 272 cylinder kit to make them a 272.
Some of the 266's have a different intake block, but you wouldnt be putting a 272 kit on those anyway as it's no better than the factory cylinder.
The white top 61 I built for my buddy with a AM 272 kit ended up with the 61's intake, carb and air filter with home made gaskets. The AM intake leaked, the gaskets sucked and leaked and the AM 272 carb was junk. I ported the cylinder a bit, it's pretty strong but I dont have a OEM 272 to compare it to, in theory the smaller carb holds it back but it cuts at like 10000rpm with the bar buried.

 

[zandrew77]

What you see on the exhaust side could easily still be used. It's the intake side that is murdered.

 

[NSEric]

Are you sure the piston is only scored on the intake side? lol.
Looks like it got really hot or straight gassed.