Rebuilding a Stihl 034, should I try it?

[SteveSr]

Ok guys I picked up the saw tonight and will be getting the t-27 torx asap. For now here are some pictures of the saw let me know what you think:

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

That is the Old version. Tall tank vent, narrow air filter, round AF cover knob. Biggest issue will be the air filter... It is still available BUT you have to buy each half separately!

 

[scallywag]

First remove all that crud!

 

[scallywag]

I'd say this saw is mid way through the production life of the o34, this particular saw has the side adjuster for the chain, early saws had the adjuster at the front.

 

[SteveSr]

Milwaukee to the rescue! I realized I had a t27 bit so was able to get to work. Here are the pictures of the piston. I'll await further instruction.

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

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• dabills
• Jul 23, 2019

Things just got more complicated... and expensive. The piston is toast and the cylinder may or may not be salvageable with a fair amount of work and skill. I could sort of tell by looking at the muffler that the front of the saw had gotten pretty hot and the photos confirmed it.

You can look for a good used P&C or perhaps a good aftermarket kit. You may even be able to turn this into an 034 super or 036 with a new top end.

Now you have to find out why the top end roached. Before you start tearing it down the next step is to do a complete crankcase pressure/vacuum leak test to see if you can find the guilty components.

 

[dabills]

Cylinder needs to come off, first remove all that crud!

Can I pressure wash it?

 

[Nathan Graff]

Can I pressure wash it?

Air compressor. You could wash, but not soak in degreaser.

 

[swatbwana]

Yes that was my first rebuild a 34 super.
Great saw.

Sent from my SM-G975U using Tapatalk

 

[SteveSr]

Can I pressure wash it?

Not a good idea. You'll likely get water and crud into the crankcase and other places you don't want it.

When I strip down a saw I seal the intake and exhaust ports and get out the baking pan, kerosene and paint brushes. Finish with Simple Green and a hose to remove any remaining kerosene and crud. Let dry in sun to drive out any moisture that might have gotten into the crankcase.

However, if you tear the top end off first you won't be able to do any leak testing and won't know what killed the saw to begin with. If you are going to replace everything rubber it may not matter. For a saw this old I would replace the impulse line, intake manifold boot, and both crank seals.

 

[dabills]

Ok I'm thinking I want to

I would replace the impulse line, intake manifold boot, and both crank seals.

I'm thinking it being so old this might be a good idea... if I were to change it over to an 036 I would buy all the parts you listed for a 036 and not 034 correct? Will I be able to replace these parts pretty easily meaning are they easily accessible to a beginner like me? If I go this route can I skip the vacuum/pressure testing? The money I save can be put into the saw is my thinking. Let me know your thoughts, thanks!

 

[dabills]

Also my grandpa told me he brought it to a stihl dealer and they said it needed a new piston and they'd do it for 90. It seems like they would've done the pressure/vacuum test to come to the conclusion that would fix it.

 

[Nathan Graff]

Not a good idea. You'll likely get water and crud into the crankcase and other places you don't want it.

When I strip down a saw I seal the intake and exhaust ports and get out the baking pan, kerosene and paint brushes. Finish with Simple Green and a hose to remove any remaining kerosene and crud. Let dry in sun to drive out any moisture that might have gotten into the crankcase.

However, if you tear the top end off first you won't be able to do any leak testing and won't know what killed the saw to begin with. If you are going to replace everything rubber it may not matter. For a saw this old I would replace the impulse line, intake manifold boot, and both crank seals.

It's likely the fuel and oil lines and filters are shot, as well as the carb rubber.

 

[scallywag]

Can I pressure wash it?

In short....No!

 

[drf255]

Lots of members up by you, in case you need a hand.

That’s a later model 034, as it has the side chain adjust. Also has the small air filter and tall tank vent. When the 036 went to the PRO designation, they changed the covers and filter/tank vent. Never saw any “new style” 034, only 036 and MS360.

Measure the bore with a drinking straw or chop stick, push it all the way to the intake side of the bore, then turn flywheel and crimp it with the piston crown. Take out straw and measure. Should be 46mm, but you never know. 034 standards with the side adjust are reported to exist, but I’ve only personally seen supers with the side adjust.

Your most important issue is to go through that entire saw and see WHY it’s scored. If you don’t do that, you’ll just ruin your next piston and cylinder. Go through it and report all here, members will help you through the build.

If the intake boot and AV mounts aren’t torn, they are fine to reuse. The fuel line is another story, it should be replaced, but you likely need the old style straight line which is tough to find. The tank can easily be drilled for the larger new style “S” line.

Lots of stuff to cover. Takes lots of pics and post questions here.

 

[cuinrearview]

I was thinking the same thing, that it could be an "S". I haven't seen a side adjust 46mm either but after so many years who knows what parts could have been swapped. If the OP wants to keep costs down I have a good used OEM 034 46mm piston and cylinder I could send his way. You'll definitely need to discern the cause of the scoring first though.

 

[dabills]

Lots of members up by you, in case you need a hand.

That’s a later model 034, as it has the side chain adjust. Also has the small air filter and tall tank vent. When the 036 went to the PRO designation, they changed the covers and filter/tank vent. Never saw any “new style” 034, only 036 and MS360.

Measure the bore with a drinking straw or chop stick, push it all the way to the intake side of the bore, then turn flywheel and crimp it with the piston crown. Take out straw and measure. Should be 46mm, but you never know. 034 standards with the side adjust are reported to exist, but I’ve only personally seen supers with the side adjust.

Your most important issue is to go through that entire saw and see WHY it’s scored. If you don’t do that, you’ll just ruin your next piston and cylinder. Go through it and report all here, members will help you through the build.

If the intake boot and AV mounts aren’t torn, they are fine to reuse. The fuel line is another story, it should be replaced, but you likely need the old style straight line which is tough to find. The tank can easily be drilled for the larger new style “S” line.

Lots of stuff to cover. Takes lots of pics and post questions here.

Ok thank you for that info I'll check to see if it's 46mm or 48mm. So far in this thread I've been told it's early model, mid model, and late model. Any serial numbers or anything I can look for to verify? Would you recommend vacuum/pressure test?

I was thinking the same thing, that it could be an "S". I haven't seen a side adjust 46mm either but after so many years who knows what parts could have been swapped. If the OP wants to keep costs down I have a good used OEM 034 46mm piston and cylinder I could send his way. You'll definitely need to discern the cause of the scoring first though.

Thank you so much for the offer. I will see what I can find out concerning the cause of the scoring.

 

[drf255]

It doesn't matter if it's an early or late saw. The 034 was 46mm and came in front or side chain adjust, the really late ones had the side adjust. It morphed into the 034S aand then the 036/MS360.

You have the "old style" 1125 model rear end, meaning, the non compensating air filter and a rear cover that locks with a knob (not lever) to the air cleaner. The carb doesnt have a compensating horn on the lower metering cover.

It's a good model. You will have muffler issues upgrading to the 036 jug, as well as a top cover that wont fit over an 036 jug (but will over an 034S jug) unless you trim the front air dam.

 

[drf255]

A vac test would be mandatory. The fuel system leaning out could be another cause for your scoring issue, that could be anything from the fuel filter to the carb jet and also the tank vent.

 

[dabills]

Ok we've reached a consensus, vacuum/ pressure test will be the next step. I'm going to call a stihl dealer this morning to get a quote on that, if it's too much I may buy the cheap harbor freight vacuum tester and do it myself which would make this project a whole lot more entertaining for you guys to watch - me trying to figure that out

Thanks for all the help so far!

 

[Mad Professor]

Ok we've reached a consensus, vacuum/ pressure test will be the next step. I'm going to call a stihl dealer this morning to get a quote on that, if it's too much I may buy the cheap harbor freight vacuum tester and do it myself which would make this project a whole lot more entertaining for you guys to watch - me trying to figure that out

Thanks for all the help so far!

Get a mighty vac, save $$$ to have it tested.

Clean it all off first. Pull flywheel and clutch too, before teardown or vac/pres test. You'll want those off to put in new seals anyway, that come with an OEM gasket kit. You might want to get a flywheel puller too. Those tools are ~ $70, how much will dealer labor be?

Tools you will always be yours. You can use a mighty vac to bleed brakes on your cars/trucks, when you are all alone.

Cleaning: Scrape off all the thick stuff, paint scraper, screwdiver, some places (cyl fins/crevices) a stiff piece of coat hanger. Then diesel/kero, a stiff parts brush or used stiff toothbrush. Paintbrushes are too wimpy. Finish with dish detergent or simple green.

Here is a formerly filthy 038 before I pulled a cyl

 

[dabills]

Ok if I can't find someone to do it cheaply I'll get the mighty vac. Question for ya, is everything I need included in the mighty vac package? If not what else will I need to get while I'm at harbor freight? Can I get by without a flywheel puller or do I need it? Are there any other tools ya'll can think of besides the t27 torx that I should pick up to finish this project while I'm at harbor freight? Thanks!

Edit: would this work?
https://www.amazon.com/Copap-16PCS-...mp+tester+kit&qid=1563988946&s=gateway&sr=8-5