Stihl 064 "jerk" when starting

[smcgarrity]

Howdy folks...I believe this is my first post after lurking for quite some time.

Got an 064 that I picked up from a friend that's seen some use, but it would start consistently for me and ran strong. After using it for a few weeks on some bigger oak, I took it in to my local Stihl guy for once over. Well, he couldn't get it to start. The pull string would consistently jerk out of his hand. This would happen to me from time to time, but I could always get it to start. He says it isn't locked up and the flywheel looks good and something along the lines of the keys being clean/in the right place (sorry, not a small engine guy). This guy's been working on Stihl's for 20+ years, usually knows his stuff, and I've taken many a saw to him. His nephew was a Stihl certified mechanic and he couldn't get it to start either and experiences the same "jerk". I've experienced this before with the saw but could always get it to start by drop starting...which I know isn't ideal. When it jerks, it feels like its going to rip your fingers out...but man I dig that saw and I'd like to hold onto for as long as I can. I am going to pick it up from the Stihl guy here this weekend and I'm hoping I can get it to start again. But the Stihl mechanic says "no luck...I can't get it to run".

I understand that this can be normal on many of the older, higher compression saws (064s, 066s, etc). The guy who sold it to me said his old man couldn't yank on it anymore...so maybe that's just the way it is? Got to muscle that thing or she'll eat my damn fingers off!

Any advice/tips?

 

[HarleyT]

Why did you take it in?

 

[cuinrearview]

Said for a "once over"

 

[Mad Professor]

Fuel pooled up in bottom end? Does it do only after sitting a while , or on warm starts too?

 

[CausticUC]

The saw recoil jerks back or by jerk do you mean the recoil stops?

They are very different things.

 

[smcgarrity]

Recoil stops.

Feels like it’s hitting something, metal perhaps. Has a “ting” sound when it does catch/jerk. It usually did that when I half-assed it...it’s almost like you’ve got to really commit to pulling that chord (when drop starting) and it’d fire up. I’m guessing the same thing is going to happen when I pick it back up.


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[CausticUC]

Recoil stops.

Feels like it’s hitting something, metal perhaps. Has a “ting” sound when it does catch/jerk. It usually did that when I half-assed it...it’s almost like you’ve got to really commit to pulling that chord (when drop starting) and it’d fire up. I’m guessing the same thing is going to happen when I pick it back up.


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Do you know if the piston has ever been changed?

 

[CausticUC]

Do you know if the piston has ever been changed?

Would almost suspect that either the piston is in backwards or that one of the ring gaps might be incorrect.

Most pistons are not truly round.

 

[HarleyT]

Said for a "once over"

Yeah, but why?

 

[HarleyT]

One doesn't normally bring it in, unless there is a reason.

Could be a buildup of carbon in the cumbustion chamber, or just flooding.

 

[smcgarrity]

Yeah, but why?

I buy an older saw I like to take them to someone who knows Stihl and knows small engines. Usually, I’m not charged bc I do other business with these folks and they do good work and I trust them. And the guy likes seeing/working on older saws.

It wasn’t for anything in particular. It’s just what I do.

Make sense? Help you any here?

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[HarleyT]

Yeah, I try to get the full story, because there usually is more details.

Did they look for any carbon buildup on the piston?

 

[HarleyT]

Do you have a nice long pull rope?

Or is it one of those retied-reknotted deals?

 

[jltrent]

Just a guess, could the key in the flywheel be in the wrong slot as they have two slots or at least some of them do.

 

[Ax-man]

Those saws should have had a decomp valve put in them from the get go.

I had to replace a module one time in mine . Then we had to get another flywheel because the timing was way to far advanced but you could tell this was the problem from the get go. I took the saw to the dealer and they couldn't believe how hard it was to try and start that saw.. . They got in touch with some Stihl tech at their distributor because they hadn't run into this this kind of problem. We finally got the problem solved once we got the correct fly wheel for that new module .

 

[smcgarrity]

I’ll be sure to get some more info when I pick up the saw.

It sounds like this shouldn’t be an issue based off of what you guys are saying but I’ve also read that these saws can be a pain in the ass to start if you don’t give it strong, committed pull.

I do appreciate the feedback though!


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[smcgarrity]

Going to side track this thing...you guys recommend anyone who works on these older stihls who can do some mods/performance work?

Thanks
Shannon


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[CausticUC]

Going to side track this thing...you guys recommend anyone who works on these older stihls who can do some mods/performance work?

Thanks
Shannon


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Look for the racing family shop in your region.

Here in the PNW it is Walker out of Nanaimo or Baker out of Edmonton. Different shops approach it different ways.

I saw a funny thread asking about Bakerized saws; in a large part of their work they ceramic heat coat the cylinder and some other parts so they can run hotter without blowing up.

Walker does some of the more extreme porting but they guarantee their work.

I am sure there are racers in WA and OR as well, I just havent run across them around here.

 

[Yotaismygame]

Ton's of guys on this site and the other one who build and port saws. Myself included. Problem I find with the big names is their prices. Lots of less known builders who do quality work for less.

 

[smcgarrity]

OK, talked to the mechanic. No fouling on piston, it's clean. rings are good. flywheel is good. only 1 key position and everything is ok there. its all OEM from what he can tell. not flooding.

he says its firing too early/timing is off. it has no decomp valve. it doesn't lock up or jerk when the spark plug is out, you can get a full pull of the cord...but he doesn't believe its a compression issue. spark plug wire was pinched and he put a new one on there and a fresh spark plug. I asked him about the ignition coil and he's going to check the shop and put one on there to see if that does anything. other than that...he's at a loss on this thing.