Stihl 038 AV Super to Magnum Conversion

[Cloudfeather]

This was a piece of dead standing ash in my backyard. I didn't delete the base gasket, but I did run the cylinder over some 220 on my glass sanding block to lower it a tiny bit. Compression right after the rebuild was 150, hoping for about 160 once I get her broken in. I did a slight port on the cylinder(just cleaned up the casting flaws and smoothed things out), and opened up the muffler a tiny bit. In this video, I leaned into it quite a bit. The bar and chain is 20" full comp chisel, 3/8 pitch and .050 gauge.

I didn't video, but I had it buried in the trunk of the tree while bucking and it hardly flinched at it.

 

[Cloudfeather]

I forgot...it was an aftermarket P&C kit from eBay. 45 bucks. It needed a little TLC, but she runs beautifully. Only time will tell for longevity.

 

[a. palmer jr.]

I doubt you'll have to worry about longevity as long as you keep a good fuel mixture in it and don't lend it to anybody..

 

[Cloudfeather]

I just meant on the cylinder. I hear some say the AM are no good. And nobody touches her but me. I've basically rebuilt it, piece by piece, over 3 years. She's my baby. Lol

 

[Adam08ski]

I just meant on the cylinder. I hear some say the AM are no good. And nobody touches her but me. I've basically rebuilt it, piece by piece, over 3 years. She's my baby. Lol

I have a farmertec/huztl cylinder and piston with caber rings that is on it. Cleaned up a bit of flashing on the transfers and skimmed the bottom face a touch. Can't really fault it. Bevels are all there and it feels smooth pulling it over with a touch of fuel mix poured into it. Compression is really good with those cabers. It doesn't look any better or worse than the cylinders that come with meteor or hyway. The casting looks neater on the outside of those but the ports and the inside of this look pretty tip top. Hope it performs nicely with the base delete and the muffler mod that I have done.

 

[a. palmer jr.]

My 038 has aftermarket P/C, don't remember the brand, but it has the regular AM rings and all and it seems to be doing okay, wouldn't want any more compression or I couldn't pull it over, starts on about 5 pulls cold after sitting for a week or so..

 

[Cloudfeather]

It must be my lucky week. Found out that my friend's uncle has an 038 Mag II that "ran great until I dropped a tree on it and broke the tank". Says I can have it for 100 bucks. If everything else is snappy on it, I'm gonna snag it up. Maybe do a little hot rodding on it.

 

[a. palmer jr.]

Try to out in stock condition first, bet you'll like it..

 

[president]

Got a video of her in action today. She's still breaking in and I need to adjust the carb a tad when I'm done, but I'm just tickled with the results. Any critique is welcome. Thanks.

NICE,seems to take a while to return to idle,might want to fatten the low screw a tad

 

[Cloudfeather]

Thanks for the advice. It tuned out to spec, but the idle seemed a bit high after breaking it in a bit. Should I tune it from scratch or just richen the low screw a bit?

 

[president]

Thanks for the advice. It tuned out to spec, but the idle seemed a bit high after breaking it in a bit. Should I tune it from scratch or just richen the low screw a bit?

search this site for tuning from scratch.I detected the long descent to idle suggesting a (too lean ) low screw setting

 

[Cloudfeather]

Ok, so here's a funny predicament. When i first rebuilt, she tuned out fine. I tuned the high side to about 12,000 - 12,500(I prefer to run a tad rich). After breaking in a bit, I went to tune it from scratch, the same way I did originally, but she peaks out at about 11,000 rpm with the high side needle buried. Any thoughts?

The carb is new from my local dealer, part number 1119 120 0605. From my research, I found that it's an equivalent to the Bing or Tillotson. Link below.

http://www.baileysonline.com/Chains...tor-for-Stihl-038-Chainsaws-1119-120-0605.axd

Any help would be appreciated.

Ps. - I'm running the fuel mixture at about 40:1 and I'm on my third tank, so I added a dash more 2 stroke to the tank. I also tried tuning with and without the air filter on. Ony about a 500rpm difference.

 

[president]

[QjUOTE="Cloudfeather, post: 6129549, member: 142572"]Ok, so here's a funny predicament. When i first rebuilt, she tuned out fine. I tuned the high side to about 12,000 - 12,500(I prefer to run a tad rich). After breaking in a bit, I went to tune it from scratch, the same way I did originally, but she peaks out at about 11,000 rpm with the high side needle buried. Any thoughts?

The carb is new from my local dealer, part number 1119 120 0605. From my research, I found that it's an equivalent to the Bing or Tillotson. Link below.

http://www.baileysonline.com/Chains...tor-for-Stihl-038-Chainsaws-1119-120-0605.axd

Any help would be appreciated.

Ps. - I'm running the fuel mixture at about 40:1 and I'm on my third tank, so I added a dash more 2 stroke to the tank. I also tried tuning with and without the air filter on. Ony about a 500rpm difference.[/QUOTE]ijust a thought,the zama carbs can be hit or
miss if you can get a bing,or tilly after modding the base holes (older cases ) may solve the 11000 rpm issue

 

[Cloudfeather]

I ended up retunimg from scratch again. Same issue. So, i leaned out the low until the idle hit about 3000, then backed off the LA until it hit 2500. Got the high at about 12,500 now and throttle response/return seems to be good.

We'll see how she does.

 

[president]

the zama carbs can be hit and miss.make sure the coil and flywheel magnets are clear of gunk
and set properly.Good luck with it

 

[a. palmer jr.]

looking at the pictures I think mine has a Bing clone carburetor on it. Sure works better than the old Tillotson it had on it. Of course a new carb should outperform a 20 some year old one. I just looked it up and I guess it's closer to 30 years old.