Stihl 064av revs but has no power

[northmanlogging]

Throwing myself to the wolves...

Anyway saw shop found this gem in the D.E.D pile, thought of me and presto, i'm the "proud" new owner of an 064...

Well, it needed a piston and cyl, as well as a new crank bearings etc

Flash forward a few days and a few nights of smacking things with hammers... (next time I'll just heat the cases and let them drop apart... lessons learned...)

Got myself a used cylinder and after market piston of unknown origins, a new Italian crank and stihl packaged japanese bearings. Saw feels like its got compression, though I have not tossed a gauge at it, even though I have one.... why do **** right, right?

slap er all together, ignoring the broken tabs from said hammering, and she fires up

Well, she revs ok, and idles just fine, but has less power then my poor abused (and now retired) ms260. Messed with the carb a bunch from way too lean, to nearly fouling plugs, and nothing seemed to make it get better.

I'm hoping this is some kind of fuel/air issue, and not the $75 wasted on used junk, Granted a new stihl p+c is only like $270, I'm already into this saw about $300, which albiet is $300 more then I payed for it, I'd rather not have to put that much more into it

Also I've had this thing completly apart, from coil to carb, well... the carb stayed attached to the handle, as it looked clean...

Thoughts?

P.S. original detonation factor was a crap rebuild, one of the cyl bolts was stuck in one of the cooling fins, just like hanging out... the other three, one of em was what some might consider tight... not to mention some critical missing exhaust parts... I found chunks, I mean chunks of piston in the muffler... she leaned out hard and fast...

 

[jmssaws]

If it starts and idles it's got enough compression.
What rpm is it tuned to?
Try it with the air filter off?
Is the flywheel and coil correct?
Muffler stopped up?

 

[northmanlogging]

Muffler clean, tried 2 diiferent filters and no filter same same.

I sure hope it coil issues, gets good spark but maybe not good spark when it needs it?

I will try and throw the comp tester at it tonight... no idea how to set the timing correctly

 

[rupedoggy]

Might be the wrong flywheel or set into the wrong key way.

 

[jmssaws]

Post a pic of the coil

 

[jmssaws]

What rpm is it tuned to?

 

[northmanlogging]

What rpm is it tuned to?

Wfo i taint no fancy saw wrench i tune em till they 4 stroke a little at wide open and dont puke when ya mash the throttle

 

[John Lyngdal]

I'll suggest a vacuum leak. Had the same symptoms with my Stihl FS86, in that it would come up to speed(slowly) but had close to zero power. Found an air leak at the cylinder gasket was the cause, as soon as I addressed that issue all the engine came back to full performance.

 

[jmssaws]

Wfo i taint no fancy saw wrench i tune em till they 4 stroke a little at wide open and dont puke when ya mash the throttle

Is it limited?
Pic of the coil?

 

[northmanlogging]

Not sure on the limited, "electric quick stop" but not annoying blinky red light like the ****** 066's had...

be a few days on getting pics of the coil, 12 hr days make it hard to mess with anything when I get home...

Did test compression came out to 118 cold after 3 pulls

As far as vacuum leak, I'm gonna say probably not, unless its at the impulse line, new gaskets, and rtv black on everything (spenders and belt kinda guy) that and I may have dented the sealing surfaces a little trying to get it apart. Don't freak out mang, just a smear to cover any gaps didn't wad the shizz on like some hill billy shade tree mucka mecky mekki wrench jocky

 

[northmanlogging]

an update

Took it into the saw shop, good shop, know their shizz...

Anyway, sounds like the chinesium piston is ****, I noticed the skirts where a little narrower, but ignored it and installed anyway... so its basically running like its trying to lean out but not actually leaning out, and getting super hot in the process.

Should have bought Stihl... this chinese garbage is a waste

 

[BuckthornBonnie]

Jug still ok? Meteor pistons are nice for this model if OEM is out of reach.

 

[northmanlogging]

cyl is kinda iffy too.

I trust stihl stuff. And this saw if it ever runs right will probably be one of my main falling saws. Fills the gap between the 461 and the 066, power to weight is ridiculous.

 

[northmanlogging]

So that chinesium piston...

was wacking the crank, and the skirts are too narrow...

installed Stihl parts... runs like a baboon on meth.

 

[Westboastfaller]

So it was mismatch p&c? Was the ports widend? Do you have the two old pistons? Stick the old rod in the ends of them to compare heights and skirt length. Some of those AM looper style open skirts look really narrow but they cover. I don't waist my time with them again. I pulled out a perfectly good running 266 window dome piston out of my 372 with a ton of jam and installed that little light looper. Mainly because I didn't cut the chamber probably so I wanted to fix it by cutting more and installing the higher 266 AM piston with out havong to machine a dome.Dumb idea! It didn't have the weight or quality to heat transfer. Got into a bunch of 3 &4ft solid cottonwood an flat ground doing machine assist one after the other and it was done after about 6 or 7.
Think it was my 2nd of third day.

 

[northmanlogging]

Skirts where hittin the crank and they are a touch narrow letting it draw a little too much air around them.

Cylinder was nearly shot anyway but it was cheap... lessons learneded