Stihl 038 Gamble/build?

[aesache]

OK so i bought a plain jane 038 for 50 bucks today came with 2 bars and 6 chains but was real tight to pull over.
i figured i would try to get this thing running again as these are pretty bullet proof saws. During that process i bet i will have a lot of questions on the way.

is there a way to tell what year the saw was?

i will be tearing into this thing tonight.

View attachment 298905
This is as i bought it
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side 2
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after a good clean
View attachment 298908
i will be pulling the muffler off tonight to see what awaits

 

[aesache]

ok i couldn't wait till tonight.

i pulled off the muffler and found the following does not look good

View attachment 298917

piston is dead. I have never seen a saw with this much junk under the covers.
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Here is another pic of the drive sprocket. Looks to me like the guy i bought it from was using a dull chain more often than not.
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Pic of the spark plug, I am by no means an expert but this looks pretty lean to me.
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And last but not least here is a pic of the cylinder. I am going to try and reuse this as alot of the aluminum transfer simply wiped off. there is no ridges and is smooth to the touch apart from the transfer
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Does anyone know of a good place to get a piston for this saw? I am in ontario. Also what is the most common cause of a lean burn on these saws? it would be a shame to put this thing together and have the same thing happen.

 

[harrygrey382]

It either has an air leak or was straight gassed. When you're pulling it down inspect the intake boot, fuel lines and I'd replace the crank seals. I'd also replace the piston and cylinder with a magnum one giving you 72cc

You're right about them being bullet proof though.

 

[aesache]

It either has an air leak or was straight gassed. When you're pulling it down inspect the intake boot, fuel lines and I'd replace the crank seals. I'd also replace the piston and cylinder with a magnum one giving you 72cc

You're right about them being bullet proof though.

i am hoping not to have to do crank seals i was going to pressure test the bottom end by blocking of the intake and exhaust ports and adding air through an adaptor in the sparkplug hole. What psi should i put in it and how long should it hold for to verify good crank seals.

you were right about the intake boot though here is a pic of mine. i suspect this was the culprit
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i did notice something out of the ordinary. This saw has a Bing carb on it, i am starting to wonder if this thing is a super or maybe i will get lucky and it will turn out to be a magnum. tonight we will see. here is the carb
View attachment 299077

 

[harrygrey382]

i am hoping not to have to do crank seals i was going to pressure test the bottom end by blocking of the intake and exhaust ports and adding air through an adaptor in the sparkplug hole. What psi should i put in it and how long should it hold for to verify good crank seals.

you were right about the intake boot though here is a pic of mine. i suspect this was the culprit




i did notice something out of the ordinary. This saw has a Bing carb on it, i am starting to wonder if this thing is a super or maybe i will get lucky and it will turn out to be a magnum. tonight we will see. here is the carb
View attachment 299077

the photos didn't load when I commented. It's a magnum - late model name tags and you can see where the magnum sticker came off. Made in brazil means it's a magnum II. Either get an OEM or Meteor piston, OEM rings, new intake boot and so long as the cylinder wall is nice you should be good. Just see how it runs then worry about air leaks

 

[Moparmyway]

the photos didn't load when I commented. It's a magnum - late model name tags and you can see where the magnum sticker came off. Made in brazil means it's a magnum II. Either get an OEM or Meteor piston, OEM rings, new intake boot and so long as the cylinder wall is nice you should be good. Just see how it runs then worry about air leaks

This could NOT be further from the truth if you closed your eyes and tried to imagine a lie !!!!

Pressure test the thing with the exhaust and intake blocked off. You already have found a huge leak in the intake, why go to the trouble of basically rebuilding it without making sure the case halves and crank seals are in good working order ???

OK, so its a Magnum ......FANTASTIC..... you have yourself a wicked 038, make it live up to its heritage and ensure the case is good with an extra 15 minutes of your valuable time ........ it could mean the difference between a saw that gives years of cutting compared to a saw that only lives 5 minutes


Sorry ............. too many XXX's again

 

[Red Amor]

How are you going with the refurb of this saw
I have one its a might old thing going very well
I wonder if you will muff mod it and just what youll do
if you do could you show pictures please
Thanks yeah

 

[Abflyboy]

Crank seals are a piece of cake on an 038. If you don't do them now, you will be doing them later and maybe another piston. :angry2:

Keep in mind, ALL the rubber parts on the saw are at the same level of deterioration. Fuel line, impulse line, intake boot, crank seals, and carb kit add very little cost compared to the value of the saw and peace of mind. I would hate to see another piston get torched.

 

[nmurph]

This could NOT be further from the truth if you closed your eyes and tried to imagine a lie !!!!

Pressure test the thing with the exhaust and intake blocked off. You already have found a huge leak in the intake, why go to the trouble of basically rebuilding it without making sure the case halves and crank seals are in good working order ???

OK, so its a Magnum ......FANTASTIC..... you have yourself a wicked 038, make it live up to its heritage and ensure the case is good with an extra 15 minutes of your valuable time ........ it could mean the difference between a saw that gives years of cutting compared to a saw that only lives 5 minutes


Sorry ............. too many XXX's again

I rebuild saws without pressure testing them all the time. It simple enough to know if you have an air leak by the way the saw idles and runs. That's not to say I am taking short cuts in quality. Just that if a saw cranks, idles, and runs as it should with no creeping idle or WOT, then an air leak is unlikely. P/V tests have their place and I use them in unexplained failures. But with this saw the intake is the obvious culprit. Doing a P/V test is unnecessary. When it is back together and not running right, then I would P/V test. But I doubt it would be necessary.

I also agree with Harry that I would replace the crank seals. It's an easy, hour long job and will eliminate one more possible failure point in the future.

 

[harrygrey382]

I rebuild saws without pressure testing them all the time. It simple enough to know if you have an air leak by the way the saw idles and runs. That's not to say I am taking short cuts in quality. Just that if a saw cranks, idles, and runs as it should with no creeping idle or WOT, then an air leak is unlikely. P/V tests have their place and I use them in unexplained failures. But with this saw the intake is the obvious culprit. Doing a P/V test is unnecessary. When it is back together and not running right, then I would P/V test. But I doubt it would be necessary.

I also agree with Harry that I would replace the crank seals. It's an easy, hour long job and will eliminate one more possible failure point in the future.

You just said word for word what I meant, I just didn't explain myself fully. If you can't tell whether a saw has an air leak as soon as you start it then you shouldn't be rebuilding saws. And those few seconds of your runnning diagnosis will not damage a new P&C. You don't even need to run at WOT, it'll just idle crazily. I've rebuilt and repaired heaps of saws and other 2 stroke equipment and never used a pressure tester - just use your ears when it's running, inspect all seals and you're ahead.

Also, once you have it complete and tuned and running perfectly, the mixture screws should be in the region of 1 turn out each. If they are much further out that's another indication one of the seals (not just crank seals though) may not be quite right. But so long as it is tuned and running correctly, and doesn't change, it should be ok. But you really have to know what running correctly is

But as the crank seals are not a major pain in the arse as others have said I would do them regardless. It also lets you inspect the whole saw properly.

 

[aesache]

ok guys i need some advice going to order parts this week.

my local saw shop has a chinese topend kit for this saw for just under 60 bucks with tax. I was thinking of going for it and trying my hand at a port job. I figure if i mess it up it was only 60 bucks not 275 for the Stihl replacements. if all turns out when it/if it blows up i will do the same with my stock cylinder and put a meteor or espian piston in it.

Am i going to waste my time with this chinese kit? saw will only be used a few times a year but when i do run them its usually pretty hard. I do a bit of csm in big wood, maple, mahogany, ash, walnut and alder... I know what your are thinking and settle down i am not milling with the 038 but it would be used as a backup saw to my 372 to section the wood and some of it is 4-5 feet in diameter. I was even thinking of doing a comparison test with stock cylinder vs the ported.

thoughts i am going to order the parts friday (payday)

 

[Moparmyway]

I rebuild saws without pressure testing them all the time. It simple enough to know if you have an air leak by the way the saw idles and runs. That's not to say I am taking short cuts in quality. Just that if a saw cranks, idles, and runs as it should with no creeping idle or WOT, then an air leak is unlikely. P/V tests have their place and I use them in unexplained failures. But with this saw the intake is the obvious culprit. Doing a P/V test is unnecessary. When it is back together and not running right, then I would P/V test. But I doubt it would be necessary.

I also agree with Harry that I would replace the crank seals. It's an easy, hour long job and will eliminate one more possible failure point in the future.

I usually just swap seals as well, and dont P/V test unless I have to, but the OP isnt too experienced and probably will take longer to tear it down again if he cant tune it at startup. If it were a more experienced dude, you could say that looking over the saw and finding the cracked boot was good enough to keep moving ..... but having him P/V test the saw will give him more time working on it, and then he can be sure of what to do next, as well as being sure that if it dont run correctly at startup - there is a couple of less culprits to look at.

 

[Moparmyway]

ok guys i need some advice going to order parts this week.

my local saw shop has a chinese topend kit for this saw for just under 60 bucks with tax. I was thinking of going for it and trying my hand at a port job. I figure if i mess it up it was only 60 bucks not 275 for the Stihl replacements. if all turns out when it/if it blows up i will do the same with my stock cylinder and put a meteor or espian piston in it.

Am i going to waste my time with this chinese kit? saw will only be used a few times a year but when i do run them its usually pretty hard. I do a bit of csm in big wood, maple, mahogany, ash, walnut and alder... I know what your are thinking and settle down i am not milling with the 038 but it would be used as a backup saw to my 372 to section the wood and some of it is 4-5 feet in diameter. I was even thinking of doing a comparison test with stock cylinder vs the ported.

thoughts i am going to order the parts friday (payday)

You will not be too happy with those kits .............
I would suggest that you try to find a good OEM cylinder for it, a Meteor piston and Caber rings.
Wasnt your cylinder in decent shape ?
Maybe just get a Meteor piston with Caber rings ......... I got mine from Baileys (site sponsor)

 

[aesache]

You will not be too happy with those kits .............
I would suggest that you try to find a good OEM cylinder for it, a Meteor piston and Caber rings.
Wasnt your cylinder in decent shape ?
Maybe just get a Meteor piston with Caber rings ......... I got mine from Baileys (site sponsor)

My stock cylinder is in great shape it cleaned up with a little steel wool and some muratic acid and looks like new. I was just thinking of trying my hand at porting a saw. Since i have never done it then i didnt want to try it on an OEM part. I was thinking that if i mess up the chinese cylinder during my port attempt i can at least use the piston in the OEM cylinder.

These chinese things really just dont hold up though eh?

 

[gunnusmc03]

My stock cylinder is in great shape it cleaned up with a little steel wool and some muratic acid and looks like new. I was just thinking of trying my hand at porting a saw. Since i have never done it then i didnt want to try it on an OEM part. I was thinking that if i mess up the chinese cylinder during my port attempt i can at least use the piston in the OEM cylinder.

These chinese things really just dont hold up though eh?

It's not that they don't necessarily hold up, some are just shoddy quality. Some are cast better than others, some are way off as far as port shapes/locations and other features go.

 

[Mad Professor]

I would not put a POS Chi-COM piston in an OEM cylinder. Get OEM, Tecomec, or Meteor.

Also note that 038 cylinders were sized A or B, and they take the corresponding A or B piston. Stihl also made an intermediate A/B piston that was acceptable for either A or B cylinders. (The cylinder should be marked A or B)

You want about 0.0025-0.003 " clearance. I would also check ring gap if mixing and matching any parts but OEM.

 

[tomdcoker]

How are you going with the refurb of this saw
I have one its a might old thing going very well
I wonder if you will muff mod it and just what youll do
if you do could you show pictures please
Thanks yeah

If it is a Magnum it should have a dual port muffler. Tom

 

[Abflyboy]

My stock cylinder is in great shape it cleaned up with a little steel wool and some muratic acid and looks like new. I was just thinking of trying my hand at porting a saw. Since i have never done it then i didnt want to try it on an OEM part. I was thinking that if i mess up the chinese cylinder during my port attempt i can at least use the piston in the OEM cylinder.

These chinese things really just dont hold up though eh?

I put a Chinese cylinder on my 038. It made it through 6 or 7 tanks of fuel, if that, and started flaking off the CHROME lining. Then it lost a bunch of power, as you can imagine.

I put a good used Stihl cylinder on it and Meteor piston with caber rings. I can't speak for all the Chinese cylinders, but I don't think I will ever use another one.

Every saw I own is ported. My first port job was that Chinese 038 cylinder. It was much more difficult than any Stihl or Husqy cylinder I've done since.

 

[aesache]

I put a Chinese cylinder on my 038. It made it through 6 or 7 tanks of fuel, if that, and started flaking off the CHROME lining. Then it lost a bunch of power, as you can imagine.

I put a good used Stihl cylinder on it and Meteor piston with caber rings. I can't speak for all the Chinese cylinders, but I don't think I will ever use another one.

Every saw I own is ported. My first port job was that Chinese 038 cylinder. It was much more difficult than any Stihl or Husqy cylinder I've done since.

ok its settled then i will order the Meteor piston and caber rings this friday. i will attempt a "clean up" Job on the ports hopefully in the next couple of weeks i can get it together.

thanks everyone.