How to re-break in a ring?

[Fordiesel69]

I rescued a cheapo 2015 era craftman handheld 25cc 2 stroke blower from the trash and it had zero compression. It would not even move the needle.

I pulled the cylinder only to find the cylinder to be in MINT condition and to my surprize was indeed coated in some kind of cheap chrome plate.

The ring had completely carboned itself to the piston and i was able to free it up and clean everything spotless. The ring was mint after cleaning with steel wool, and the cylinder had no carbon buildup or scratches.

Upon reassembling it, I now have 40si or thereabouts and it does not start well, or idle well but it does run at WOT very good.

Why is the compression so low? Does the stuck ring need to break back in to the cylinder surface?

 

[Rand]

Does it have a compression release for pull starting?

If they have cheap carbs available for it that might fix your issue.

 

[ARCOgraphite]

If the cyl are chromed, then no wear in per se like a 4 stroke car engine with iron cylinders, Sound like one of the carb circuits is gummed, but also sounds like how most cheap
2 strokes operate. The last great "cheap" one I had was a Homelite weed whacker That was a nice engine.
Walmart generic spray carb cleaner is good stuff cheap.

 

[ironman_gq]

unless your compression tester has the schraeder valve right at the end of the hose where it screws into the spark plug hole, you won't get an accurate reading. I've seen these small engines test 20-50psi on a tester with the valve near the gauge and 140psi on one with the valve in the adapter fitting. It's possible that you have decent compression and a dirty carb, it's also possible that the ring has lost tension or is worn but that's easy to check. Pull the ring off the piston and stick it down in the cylinder and check the end gap.

 

[JohnnyG]

Were you able to scuff up the cylinder at all?

 

[Fordiesel69]

Yep so I have a twin poulan blower that is identical except the color and its compression is 90 ish psi. I can actually feel it in the rope.

The ring had nice tension, had no wear that I could see, and it had very small end gap. (I genuinly did not meaure it) but im familair with eyeing them up.

Super bummed out as even with running it 45 minutes it made zero difference.

 

[tnt_motorsports]

Were you able to scuff up the cylinder at all?

not likely if it's chromed... If you try to scuff it my bet is the chrome is going to peel off...

Just my $0.02

 

[repairman54]

There is no scuffing chrome cylinders. Tons of experience with them on '70's snowmobile engines. Chrome was the go to before Nikasil was developed.
Original ring may have been moly coated and now it's worn out.

 

[Fordiesel69]

I didnt bother scuffing the cylinder as it looked mint and still retained its factory pristine cross hatch. I will most likely try a new ring for $9 bucks. Its 10 minutes to swap it out.