Stihl 034 won't start & needs top end kit

[jpan]

He all. I'm working on getting an old 034 running for a friend. This won't be his main chainsaw and will probably only get a couple of hours use a year out of it. The problem I'm having is that I can't get it to fire up at all. I rebuilt the carb, cleaned the fuel tank vent, and used a little bit of vaseline to check that the impulse line created some suction.

Pulled the muffler and noticed that the entire exhaust port side of the piston is scored badly. So, I'll get a top end kit for it. Here's where I have a few questions.

1. Any recommendations on brand? I read that the Meteor aftermarket may be the better kit?

2. This saw has a ton of oil buildup everywhere. I haven't checked yet since I don't have a pressure tester, but thinking the crank seals could be an issue. Are these pretty easy to do? I'm experienced building car engines, doing seals, etc...just haven't done them on small engines yet.

Thanks for the help!

 

[jpan]

Here’s a few pictures from the exhaust port. Sorry they’re sideways. I’ll pull the top end off later today.

E6E85BD3-181A-4FD0-A579-67ED0C24E9B3

• jpan
• Sep 23, 2019

66B27235-2C26-4112-988E-A45D086A060E

• jpan
• Sep 23, 2019

A6616C27-8FB4-458E-81A9-E77D955C14A0

• jpan
• Sep 23, 2019

 

[Vintage Engine Repairs]

Super interesting, i’ll be tuning in to responses too. I have read that air leaks can cause this so you’re probably on to something! I’ll step aside while the experienced guys chime in though!

 

[cuinrearview]

You could spend the $$ for a new top end, crank seals, fuel and impulse hose, intake boot, and still have a leak at the case gasket. You won't know what made it run lean and melt down without pressure and vacuum testing it, just like you won't be sure your assembly is good afterward without it.

If the cylinder won't clean up, I'd put a want ad for a used OEM cylinder in the trading post. Also, if you're replacing the cylinder, a 48mm 036 top end is a bolt on. The only change you may have to make is some spacing for the muffler. It's minor though.

 

[jpan]

You could spend the $$ for a new top end, crank seals, fuel and impulse hose, intake boot, and still have a leak at the case gasket. You won't know what made it run lean and melt down without pressure and vacuum testing it, just like you won't be sure your assembly is good afterward without it.

If the cylinder won't clean up, I'd put a want ad for a used OEM cylinder in the trading post. Also, if you're replacing the cylinder, a 48mm 036 top end is a bolt on. The only change you may have to make is some spacing for the muffler. It's minor though.

thanks for the insight. Is it possible to pressure test it with the scored piston and cylinder like it is or do you need to do a new top end kit first then test? Is the recommendation to do that before ordering parts?

and yeah Instead of trying to clean up the existing cylinder id rather just do an 036 top end kit and muffler so it fits in the plastics.

I should also mention that the low end fuel needle was set to 2.5 turns out and the high end was only 1/2 turn. I’ve reset both to 1 turn as a starting point when it gets back together.

 

[Totembear]

He'll have to cut out some of the top cover to make an 034 into an 036. But that and what Tim said. If not there are plenty of 034 jugs around.

 

[cuinrearview]

1/2 turn out on H could explain things.

You can bolt the bad top end back on and block the ports and get a good test, as long as the base gasket isn't comprimised.

 

[Totembear]

And yes, you can test it with the scored top end on the saw. Its better that way so you know exactly what youre getting into. ie, if its the case gasket you might not want to rebuild the saw.

 

[jpan]

And yes, you can test it with the scored top end on the saw. Its better that way so you know exactly what youre getting into. ie, if its the case gasket you might not want to rebuild the saw.

I will check that tonight or tomorrow. I haven’t pulled the top end off of it yet.

Bearings feel good though I can’t detect any play in them. Here’s photos of the oil pump behind the clutch. Something is definitely leaking.

 

[cuinrearview]

Just looks like bar oil grime to me

 

[jpan]

Any recommendations on stores that sell a pressure tester? Auto parts, big box etc?

 

[jpan]

Just looks like bar oil grime to me

It’s an old saw for sure so wouldn’t surprise me. The seal does look somewhat dry but still need to test

 

[jpan]

And yes, you can test it with the scored top end on the saw. Its better that way so you know exactly what youre getting into. ie, if its the case gasket you might not want to rebuild the saw.

How do you test the case gasket?

 

[grizz55chev]

How do you test the case gasket?

Pressure vac test, read up grasshopper!

 

[drf255]

It’s good that your going through the diagnosis before just swapping in and ruining a top end.

As the intake wall looks perfect through the jug, it does look leaned out and not straight gassed.

Vac test it first and see what you find.

That cylinder may be able to be salvaged, one never knows. Pull it after testing.

There are numerous threads on here regarding cleaning transfer off a cylinder. One very good one from @Mastermind Worksaws .

If it cant be saved, the 46mm 034 jugs are a dime a dozen. Noone reallywants them because the 48mm 034S/036 Jug simply runs better and in almost a bolt on (need possible muff spacer and some top cover from airdam work. 036 jugs are getting pricier as the supply is drying up, but who’s could probably do a meteor piston and find a good oem jug for around $125.

 

[Short timer]

Any recommendations on stores that sell a pressure tester? Auto parts, big box etc?

Get the mityvac 8500 if you plan to work on saws, it's a must have. Online is probably your best bet for lowest price, but i'm sure you can find them locally for a premium.

 

[scallywag]

Any recommendations on stores that sell a pressure tester? Auto parts, big box etc?

Here....
https://www.skf.com/mityvac/index.html

 

[jpan]

Thanks all. Going to pressure/vac test this week when I get time

 

[Wood Doctor]

The Stihl 034 AV I is hard to kill. I upgraded mine to an 036 used it today to cut a truckload of maple:

I suppose I could have used my MS361 instead, but they are really almost two peas in a pod.

 

[dmb2613]

I have a NOS piston for a 034 if you end up needing one
I have an 034 super that has cut many tons of wood. It still runs like a scalded dog after a raped ape and is light too the 034 is a good saw well worth fixing