Oldtoolsnewproblems
ArboristSite Operative
So I got a Husqvarna 266xp that is dear to me. Was my first saw (found in the trash) and the first 2 stroke tool I ever actually took apart and put back together into better shape than when I started! Was the start of an addiction but I'm getting off topic.
Fast forward and I finally have a backup saw that works better than the 266, so I figure it's time to do a recipe. Saw only ever had 90psi compression but started very easy, but clearly didn't have the power a 66cc saw should. So I bought a no name piston, did a full case tear down and rebuild. Cylinder had some discoloration but no groves so I just put in the new piston and gaskets. I deleted the base gasket to try to get a little free power, and since I wasn't sure why the compression was low. Although right before closing the case I checked the old ring, and it had about 1/8 the gap, so I think that answered that. Wich is weird to me as it looked really good inside.
Anyways new piston rings end gap looked good, don't have my notes but it makes 165psi now. Deck was like .027
Well it still has a tiny vacuum leak I can't find, loses 1psi in 5 minutes, not great but not enough to stop me from taking it for a test run. Started up instantly, idles better than it ever did, nice and low.
But now when I tune the high mixture, got it 4 stroking, it only revs to 9-10k, and is very low power in the cut. With a 22" bar it drops to look 6k in the cut best I can tell.
I'm going to try to find that leak, but I'm getting conflicting info if that is really bad enough to cause my problem, or a trivial amount. Holds pressure a little better, it's vacuum that leaks a bit faster.
My fear is that the piston is wrong somehow. And that the timing is all messed up. I didn't think ditching the base gasket would change it that much. Muffler doesn't seem clogged but I don't see an obvious way to know that. I could try running it with no muffler and ear plugs, assuming that's safe for the saw.
Looking for pointers, I've tuned and built many a vw motor, but 2 strokes are a new beast to me.
Fast forward and I finally have a backup saw that works better than the 266, so I figure it's time to do a recipe. Saw only ever had 90psi compression but started very easy, but clearly didn't have the power a 66cc saw should. So I bought a no name piston, did a full case tear down and rebuild. Cylinder had some discoloration but no groves so I just put in the new piston and gaskets. I deleted the base gasket to try to get a little free power, and since I wasn't sure why the compression was low. Although right before closing the case I checked the old ring, and it had about 1/8 the gap, so I think that answered that. Wich is weird to me as it looked really good inside.
Anyways new piston rings end gap looked good, don't have my notes but it makes 165psi now. Deck was like .027
Well it still has a tiny vacuum leak I can't find, loses 1psi in 5 minutes, not great but not enough to stop me from taking it for a test run. Started up instantly, idles better than it ever did, nice and low.
But now when I tune the high mixture, got it 4 stroking, it only revs to 9-10k, and is very low power in the cut. With a 22" bar it drops to look 6k in the cut best I can tell.
I'm going to try to find that leak, but I'm getting conflicting info if that is really bad enough to cause my problem, or a trivial amount. Holds pressure a little better, it's vacuum that leaks a bit faster.
My fear is that the piston is wrong somehow. And that the timing is all messed up. I didn't think ditching the base gasket would change it that much. Muffler doesn't seem clogged but I don't see an obvious way to know that. I could try running it with no muffler and ear plugs, assuming that's safe for the saw.
Looking for pointers, I've tuned and built many a vw motor, but 2 strokes are a new beast to me.
