064 problems. Need help

[poorboypaul]

Been on here a while. Now I need some info. Rebuilding an 064. Used an aftermarket piston and rings. New crank seals. Crank bearings seem in good shape. The problem is when the counterweight on the crank comes up, the piston skirt is bottoming out on the counterweight. Is this from it being aftermarket or is something else going on?
Another project giving me fits is an echo cs-400. New piston, rings, carb kit. Finally figured out the fuel line routing. It still has a fuel issue. Runs when primed, but dies once the primed fuel is gone. Is there a tank vent on this pos, hole in one of the lines? I'm able to tear them apart and assemble them, but need the hands-on for trouble shooting. Can't learn how to do a job by reading a book. Any help greatly appreciated!

 

[Jacob J.]

I've not had an aftermarket 064 piston rub the counterweights yet after install but you never know with the "off brand" stuff. Sounds like you'll need to take a file and do some shaping on the skirts. Did you rebuild the carb in the Echo? New fuel filter? I'm assuming you did that stuff.

 

[LowVolt]

Never done work on those saws but some one will ask, what brand was the piston? That could be useful info. Did you get the right piston? Do you still have the old one to compare side-by-side?

 

[poorboypaul]

Had the cylinder on. Noticed it would drag every turn of the flywheel. Fit good inside. I'll do some measuring on the old piston vs new. Old piston is severely scored, so I don't know how accurate of a measurement it will be. If I have to trim the skirt, I'll have a friend do it on a lathe. Didn't check the fuel filter on the echo. Saw was like new when I got it off fee bay. Knew the owner probably straight gassed it. I have another filter if it's the right size. I'll try to swap tomorrow and see what happens. Could be the problem. Sometimes I forget to "KISS".

 

[tallfarmboy]

It probably won't take work with a lathe to remove enough material from the piston to clear the counterweights on the crank... Could probably be cleaned up with a chain file or maybe a dremel.
Also, double check those crank bearings... if they had a plastic cage in them, make sure that the cage isn't broken... That would give your crank a little extra up and down play and could (maybe) be causing your crank to piston contact.

Your little echo is probably going to need a carb kit... Sounds like some saws that I have seen with dried up or hard diaphragms in them. Make sure to clean out all of the ports in the carb while you have it apart.

Good luck with your repairs!
TFB

 

[nmurph]

I can't see how bad bearings would allow a piston skirt to hit the crank weight. If the big-end bearing were bad, then yes, it could cause the skirt to hit.

OP, a file is all that is needed to shorten the skirts.

 

[cutforfun]

Could the aftermarket piston be for a 046 by mistake?

 

[mantas]

Install the P/C on the crankcase, and when the piston is at TDC the skirt shouldnt see through the inlet port

 

[poorboypaul]

Rebuilt and cleaned the carb in the echo. Saw has sat for a couple years before I got to it. Wondering if the filter might have some varnish on it. Carb was pretty clean when I opened it up. As for the 064, I had the jug on it. It's not an 046piston. Don't know how much compression it's supposed to have, but I could still turn the flywheel by hand after putting the spark plug in. Seals went in without a hitch. Guessing if there was a bearing problem, the crank would be sitting lower in the case. Will measure up the pistons today if I have an old one. If not, I'll look online for piston specs.

 

[Scooterbum]

A little raker file would take care of that skirt in short order.

 

[poorboypaul]

Thought about the lathe because I wanted to make sure it would be even. Didn't want it uneven and out of balance. Just don't know how critical it would be.

 

[Scooterbum]

Take just what you need. If you need measurements from a stock piston let me know.
Back in my dirt bike days we used to take an old piston and grind on the skirt and top to change port timing instead of ruining a good cylinder.Pistons are a lot cheaper. Didn't know anything about a degree wheel. We just went buy our "seat of the pants dyno". A lot of taking apart and back together stuff back then.

 

[Fish]

Had the same problem a few years ago putting a Golf piston on a 064, the customer brought me the piston, so I called him to give him the options. The oem piston was bevelled on the inner lip of the skirt.

Justs worked on it with a half-round file a bit, worked fine.

 

[Jacob J.]

Could the aftermarket piston be for a 046 by mistake?

The skirts are shorter on an 046 piston.

Thought about the lathe because I wanted to make sure it would be even. Didn't want it uneven and out of balance. Just don't know how critical it would be.

A piston in a single cylinder engine isn't really "balanced" for anything.

 

[Naked Arborist]

The skirts are shorter on an 046 piston.

How much shorter are they? Do they have the same cylinder bore size and pin height from the top down?

A piston in a single cylinder engine isn't really "balanced" for anything.

But yes, it is, in more ways than one.

 

[poorboypaul]

One's a basket case that's mostly intact. The other is just the case. The one I'm working on obviously has crank bearing issues. Has a tight spot when turning it, so I put the piston on the other saw. Turns smooth, plenty of clearance on the down swing. Put the jug on and everything is nice and smooth. As for the echo, I pulled the fuel filter, disassembled it, cleaned it, put it back together. Ran for about 30 seconds and quit. Pulled the filter, same thing. Going to replace the fuel lines. One on the primer bulb seemed stretched open and felt slippery. Don't feel rotted, but if the fuel has deteriorated the lines and softened them, would they suck shut when running? Got to be fuel line or screwed up something in the carb.

 

[Fish]

But yes, it is, in more ways than one.

OK, tell us without digging out your highschool physics books, and explain how filing that little smidge of aluminum is going to cause a problem?????

 

[discounthunter]

OK, tell us without digging out your highschool physics books, and explain how filing that little smidge of aluminum is going to cause a problem?????

PBM: piston balance machine. not cheap but awesome,sure is a pain to get those little weights in there though.

 

[Fish]

It checks the balance of the piston in relation to the piston pin???

The critical one on the saw would be the crankshaft....

 

[Naked Arborist]

OK, tell us without digging out your highschool physics books, and explain how filing that little smidge of aluminum is going to cause a problem?????

Never said it would cause any problems I'd take a file or cookie buffer to it and be done with it.