# Stihl 038av - Just picked it up - Few ????



## gapman789 (Nov 19, 2011)

So I just picked up this 038 av electronic quickstop locally for $65.  The guy said it would start on choke and run for a minute and die.
Compression 'felt' good on it.  I could move the chain by hand.  The brake worked, etc...The saw seemed to be in good shape except for maybe a carburetor problem.
Keep in mind, I'm no expert with saws (reference my other thread I have going on with my 036) and this was my initial analysis of the saw.

So I bring it home and take the muffler off to take a look at the piston.  It looked really good.  Also, there wasn't much carbon built up in the muffler, the screen was clean, as well as the fuel filter.  Saw is quite clean overall, especially compared to my 036 I just tore apart.

What I noticed while looking at the piston through the muffler and pulling the rope, was gas coming down the skirt of the piston on the upstroke.  It seems that maybe fuel is constantly flowing through the intake and into the cylinder.  Hence causing the saw not to fire?  Sparkplug was wet with gas.

I'm gonna go buy a compression tester tomorrow, (I've been needing one for all my motorized stuff anyway), and check that.  I should be looking at 140-160 to be good?
If that checks out ok, I'm taking it to the shop and let them look at it.  Hopefully the carb just needs rebuilt.  I thought it was a good idea for me to check for some things myself just in case the shop wants to tell me I need a new piston, or I should junk it, or I'll give ya $50 for it, etc....  It's a very reputable dealer, but I'm paranoid about getting screwed over nonetheless.

What do yas think with the info I've given?  Good chance that I got a helluva bargain?  Maybe another $100 or less and I'll have a nice running saw?!

Sorry for the bad pics....digital camera was stolen a few days ago.  The last pic was from the ad.


----------



## Bubbavh (Nov 20, 2011)

Test compression first.
I'd also check the carb boot for cracks or possible air leaks.
Let us know what you find out.


----------



## rwhite (Nov 20, 2011)

99% of the time it's a carb rebuild that is needed. Just remember that these things are dead simple machines. I start off every project with a compression test then go from there. Even if you get it running it's a good idea to take it to a shop for tuning unless you have the rpm guages. Even as much as I work on 2 strokes it's amazing what a good shop with the right equipment can do for a saw.


----------



## MasterMech (Nov 20, 2011)

Buy the kit and build the carb yourself.  It's a lot easier than some of the work your tackling on that 036.  A good score on the saw.


----------



## seeyal8r (Nov 20, 2011)

Great score on the saw. I agree to take the carb completely apart, clean, and put back together. I've done that and avoided the rebuild kits all together. Once you get it running well, i'd take it to a good saw shop for tune up. the 038's are awesome hoss machines.


----------



## gapman789 (Nov 20, 2011)

Well, just did the compression test on the saw and all it could muster was 120....
So what does that mean as far as a rebuild goes?   Is it ok and the saw will run ok or is that too weak and definitely needs a piston/ring job?


----------



## gapman789 (Nov 20, 2011)

After some more research on the site, I found that I may only need new rings if that.  Possible stuck ring(s)?  Piston looks good through the muffler, but I guess I need to take the cylinder off to really check.

I bought this from Autozone.  I saw references to the Schraeder valve? on a compression tester?  I'm assuming it's the needle valve at the end of the hose.  Looks like an air needle in a valve stem?  Just making sure this tester is ok for this application.


----------



## gapman789 (Nov 20, 2011)

So I just checked for spark.  Got plenty of that.  
Decided to try and start it.  Pulled it about 10 times and suddenly gas starting coming out from the front of the saw.  Behind/under the muffler area.  We're talking like a shot glass full of gas came out.  Not just a coupla' of dribbles.  It left a 10" puddle on the floor.

So I take the muffler off again and pull it a few times and the cylinder is just filling with fuel and getting pushed out through the exhaust port.

Diagnosis?  Obviously a fuel/carb problem which is what I was told/was thinking when I bought the saw.

In a nutshell....I've got 'should run on' 120 compression, good spark, but way too much fuel.  Next step would be take the carb off and check for broken lines/parts I assume.  Probably needs a carb kit for sure, which from what I've read, I should leave that up to the experts.
And take the saw to the shop to have it tuned.

Sound about right?  Get off the couch fellas, football's over for the day.  Bengals lost-no other games matter. lol.

Thanks for the help guys.


----------



## southbound (Nov 20, 2011)

I have a 038 did the same thing...

Was faster and cheaper to buy a after market carb on the bay...

Been a strong runner ever since....

They made style carbs for this saw you want the bing....

http://www.arboristsite.com/chainsaw/144410.htm


----------



## gapman789 (Nov 21, 2011)

southbound said:
			
		

> I have a 038 did the same thing...
> 
> Was faster and cheaper to buy a after market carb on the bay...
> 
> ...



Man, thanks.  That is the same saw/carburetor I have.  I went out and took the filter off and plug out and pulled it a few times and it appears to be leaking at that 'module plate' on the bottom of the carb.
Ebay it is.


----------



## southbound (Nov 21, 2011)

If you have that carb buy a bing copy!! Trust me...


----------



## southbound (Nov 21, 2011)

I know nothing of the seller just that this is the type carb I would look for....

http://www.ebay.com/itm/STIHL-038-M...573352237?pt=US_Chainsaws&hash=item20bad3212d


----------



## gapman789 (Nov 21, 2011)

southbound said:
			
		

> I know nothing of the seller just that this is the type carb I would look for....
> 
> http://www.ebay.com/itm/STIHL-038-M...573352237?pt=US_Chainsaws&hash=item20bad3212d



Looking at that carb on ebay, the metal inlet/tube on the bottom of the carb that goes to the right, is different than my carb.
If my carb has that same tube/pipe, it must be pointing toward the cylinder and not visible without taking it off.

Is that pic on the ebay ad a generic pic of a carb and maybe not the exact carb that I wouldn't be getting?
My carb looks EXACTLY like the one you posted at the arboristsite.


----------



## southbound (Nov 21, 2011)

That is not the fuel line...

I am sending you a pm with some stuff you need to download.. All will be answered....


----------



## southbound (Nov 21, 2011)

That thing got a metal tank???


----------



## gapman789 (Nov 21, 2011)

Plastic tank.  My carb doesn't have that bottom 'elbow' on it like the one in the ebay link.  
Looking at the other carbs on ebay, they do have the Tilly replacements that look like mine without the elbow.  I'll call that HL Supply from the ad tomorrow and find out if that pic of the carb in their ad is just a generic pic that they use for there stihl carb ads.


----------



## southbound (Nov 21, 2011)

My saw now has one that looks just like the one on the bay.. It will bolt right up and out perform the Tilly...

Did you get my pm??? I sent some really good reading


----------



## smokinj (Nov 21, 2011)

southbound said:
			
		

> My saw now has one that looks just like the one on the bay.. It will bolt right up and out perform the Tilly...
> 
> Did you get my pm??? I sent some really good reading



No I didnt,sent it again.


----------



## southbound (Nov 21, 2011)

smokinjay said:
			
		

> southbound said:
> 
> 
> 
> ...



Pm sent!!


----------



## smokinj (Nov 21, 2011)

southbound said:
			
		

> smokinjay said:
> 
> 
> 
> ...



You get mine on the bigger saw's?


----------



## gapman789 (Nov 21, 2011)

southbound said:
			
		

> My saw now has one that looks just like the one on the bay.. It will bolt right up and out perform the Tilly...
> 
> Did you get my pm??? I sent some really good reading



I did get the files and thank you.  I browsed through them.  Went to the carb section and the diagrams show that 'elbow' on the 'end cap' as it's referred to in the parts list.  Just don't know why my saw doesn't have that carb that is pictured in the parts list.  

I was thinking that the 'elbow' on the ebay carb ad had to have a line hooked up to it just by looking at it?  You're saying it's not and that's good enough for me.
I will call them tomorrow nonetheless.


----------



## southbound (Nov 21, 2011)

I just mounted mine and retuned it... Still runs great..

Call them folks and talk to your dealer they can help...


----------



## southbound (Nov 22, 2011)

any luck???


----------



## gapman789 (Nov 22, 2011)

southbound said:
			
		

> any luck???



Bought the Bing carb from the link you posted.  I did talk to them before I bought it this morning.
I will be getting the carb in the ad that does have that 'tube' on the bottom of the carb which apparently doesn't get hooked up to anything.  He called it the 'compensation' valve or something to that effect.  It' just part of the design.  Not sure of the functionality of it.

Also said he's '0' problems with those carbs and that is what I need.  They shipped it out before noon today.  Will probably have Wednesday.

Now I need to decide if I should go ahead and buy a piston kit or maybe just rings or get it running lst and see how it treats me.  I'm at 120 psi on the compression test.   I should probably go ahead and do the piston.


----------



## gapman789 (Nov 22, 2011)

gapman789 said:
			
		

> southbound said:
> 
> 
> 
> ...


----------



## southbound (Nov 22, 2011)

put on the carb and get it running before you spend time on a piston.


----------



## Singed Eyebrows (Nov 22, 2011)

gapman789 said:
			
		

> gapman789 said:
> 
> 
> 
> ...


As was mentioned, put the carb on first. The China tester you bought might also be leaking somewhere. Years ago I tested Volkswagen diesel compression with an inexpensive tester & was disapointed at how low it was. I took the car in for diagnosis & the compression was fine. I was told use a Snap On tester that positively doesn't leak. 120 is way too low though if thats accurate. I would expect a little piston smearing of the aluminum, sticking rings if it is 120. Nice looking saw at a good price though, Randy


----------



## gapman789 (Nov 22, 2011)

Singed Eyebrows said:
			
		

> gapman789 said:
> 
> 
> 
> ...



Noted.  Autozone had a compression tester to loan out.  The only name I saw on the their loaner was 'OEM'.  It seemed to be of good quality.  I'll go there tomorrow and get that and see how it compares to the 'Actron' brand I bought.


----------



## Singed Eyebrows (Nov 22, 2011)

gapman789 said:
			
		

> Singed Eyebrows said:
> 
> 
> 
> ...


 Hold the throttle wide open when testing, Randy


----------



## rwhite (Nov 22, 2011)

At 120 psi it will run. The compression guages for chainsaws are alot more delicate than any old auto guage because they don't have the volume to work some of them properly.


----------



## gapman789 (Nov 24, 2011)

UPDATE:  Got the Bing replacement carb today.  Just now put it on.  
After going through my compression testing procedure, I realize that I didn't need to add an adapter that came with the kit to the end of the air hose.  Also, when I did the test before with the old carb,  the cylinder was filling up with fuel and coming out of the muffler, which was going to give me a bad reading as well.

So, here's how I did the compression test this go round.
Remove air filter
Lock choke on
Screw hose in finger tight 
Pull 5 times or until the psi tops out ( I believe it was 5 pulls with an extra pull to make sure)

I got 150!!  

I also looked at the intake side of the piston skirt while the carb was off and it looked good as well.  
And I checked the impulse/fuel line for cracks or leaks and it was a little dry rotted where it goes into the tank, so I'll go ahead and replace that.

Now, I'm ready to try and start this thing, I think.  My concerns are with the settings on the new carb.  Are they generally set to a 'happy medium' and then need to be adjusted?  I just want to start it for now and I'll take it to the shop for a proper tune.
Can I duplicate the settings on the old carb by counting turns in and out?  Or will that be like apples and oranges?  Tilloston  vs. Bing.


----------



## southbound (Nov 24, 2011)

One of the downloads will tell you where to start...


----------



## gapman789 (Nov 24, 2011)

southbound said:
			
		

> One of the downloads will tell you where to start...



1 turn out on H/L per the manual.

So, with choke on, lst pull and it fires/runs for 5 secs.
It restarted a couple more times but died.  I take the plug out and it's wet with fuel.  I pulled it a few more times to see if gas was going to come out of the muffler like it did before the new carb and sure enough it did.

Where does that leave me?  Sticking rings?  If rings were sticking would I not have a low compression reading instead of the solid 150 which did slightly drop to 148 after about 20 mins.?

And more research begins.....


----------



## southbound (Nov 24, 2011)

gapman789 said:
			
		

> southbound said:
> 
> 
> 
> ...




You flooded it.......

Choke on all the way down pull till it gurgles....

then half choke one click up till it fires and runs.. At this point it will be running full throttle...

pull trigger and it will go from half choke to no choke and run as it should..

one more click up and you will turn off the saw..



Sounds like it is flooded I would set to half choke hold the trigger open and give it a few pulls.. It should start up..


----------



## gapman789 (Nov 24, 2011)

An added note, the breather filter is toast.  When I hold it up to the light, I can't see any light at all.  The outside screen is clean, but it's solid crud on the inside.
Guess I should stop trying to start it until I get a new filter on Friday?

Damn, starting to think that all that was wrong to begin with was a completely clogged air filter.  lol


----------



## southbound (Nov 24, 2011)

http://www.baileysonline.com/itemdetail.asp?item=QA+11191+201610&catID;=

it still should run...


----------



## gapman789 (Nov 24, 2011)

Can't get it to fire.  Cases must be full of fuel at this point.
I'm thinking that since the saw has sat for a few days, all the fuel that was in the cylinder and cases, evaporated.  So when I put the new carb on, it fired immediately...but then flooded itself out.  Which is basically the story I got from the guy I bought it from.  It would start on for a sec then die.
I'm in the concrete biz and use Stihl TS400 saws daily.  I know it's not a matter of me properly starting the saw.  Something is wrong.

And this fell out when I turned the saw upside down to 'shake' fuel out of the cases.  I know the pics are terrible.  It's a small threaded set screw of sorts.
Any ideas on what it is?

Thanks South.


----------



## southbound (Nov 24, 2011)

Idle speed adjustment screw from a tilly carb???

Really hard to tell from pic....


----------



## amateur cutter (Nov 24, 2011)

Empty the case out, put a few drops of 10w30 oil down the cylinder, this will absorb some of the excess fuel & try starting it without the air filter. I'll bet the bottom end is full of mix. A C


----------



## gapman789 (Nov 24, 2011)

I'm gonna drain the tank, cylinder, and cases to the best I can from what I've read.
Get a new plug and filter and try her again this weekend.
BTW, muffler/screen is clean and clear.

Until next time....HAPPY THANKSGIVING!!.....and thanks to all for the info...


----------



## Singed Eyebrows (Nov 24, 2011)

gapman789 said:
			
		

> I'm gonna drain the tank, cylinder, and cases to the best I can from what I've read.
> Get a new plug and filter and try her again this weekend.
> BTW, muffler/screen is clean and clear.
> 
> Until next time....HAPPY THANKSGIVING!!.....and thanks to all for the info...


This isn't one of the Stihls that has the choke built into the filter? The saw is acting like it's constantly on choke. As was mentioned, run without filter. Randy


----------



## gapman789 (Nov 24, 2011)

It is the filter with the built in choke.  So, after turkey dinner at mom's house, I just now go to the garage.  I take the filter apart and clean the inside.
The choke flapper valve is held on by a cotter pin.  I take the cotter out and the choke valve and all seems ok.
I put it back in making sure that the cotter catches the spring on the valve.  I'm thinking the filter was taken apart at some time and the cotter wasn't going through the little spring that works the choke valve.

Saw has been setting for 24hrs, so hoping that the fuel in the cases and cylinder had evaporated, I give her a quick pull with full choke and crack, we got fire, as in it hit.
I turn choke off, another couple pulls and it's firing and spitting some gas out of the exhaust port, and just a few more pulls and it started idling.  Very nice.

Muffler was off, so I didn't want to run it much and the throttle linkage/arm keeps binding up in the new Bing carb I put on it so I'm gonna have to bend it or flex it so it operates freely.  A stuck throttle on anything is never good.

Seems to be idling fast so I'll try to turn that down.  I did set the H/L according to new carb/new rebuilt carb according to the service manual.  1 turn out on each.


----------



## gapman789 (Nov 25, 2011)

Success!  It's starting, running, and idling fine.  Oiler seems to be working too.

The chain doesn't want to stay properly adjusted; becomes loose after 30 secs of running.  The bar/chain do look to be in bad shape.  I'll get new or I'm sure my local Stihl dealer has some good used bar and chains.  Though I could just put my good 20" bar/chain from my 036 on the 038?  
I'm also going to let them tune it.  

I got less than $100 in this 038, 150 psi saw.  So far, well worth it.
I guess I'll disregard that set screw that fell out of it.

Thanks again everybody.
I'll cya's at my 036 thread soon.


----------



## southbound (Nov 25, 2011)

Though I could just put my good 20â€ bar/chain from my 036 on the 038?    Yes if the same pitch chain ie 3/8

good to hear you are happy..  I too will be building a 036as soon as I get done with this 064/066.....


----------

