STIHL 1120 Series Complete Engine Rebuild (009, 010, 011, 012 Chain Saws)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Here is why you need to take the serial number with you when ordering a crankcase gasket. The Orange Screw Driver handle is pointing to the differences between the old one and the new one.
DSCF4792.webp
 
Install the cranshaft in the crancase. It does not matter which side you do first. Make sure the piston is in the corrsct location. You will not be able to turn the cranshaft while the connecting rod bearing holder is installed and the assy is in the crankcase.
DSCF4800.webp
DSCF4797.webp
DSCF4799.webp
 
This is the backside of the oil pump.

(I will do an entire seperate thread on the 1120 series oiler if one is needed.)

The top oil is missing the oil filter.

The bottom oil pump has the filter. It looks like a big sponge, because it is a big sponge. :D
DSCF4793.webp
DSCF4794.webp
 
Last edited:
Assemble the crankcase halves together and install the bolts but do not tighten the bolts.

There are two different length bolts. You have three long ones. Two of the long one go were the bumper spikes go and the third one goes in the hole near the where the carburetor mounts and the top of the cylinder.

Once all the bolts are installed but not snugged down. Drive the crankcase alignment pins in using a punch and beating utensil.

The screw driver is pointing at one of the three alignment pins.
DSCF4803.webp
 
Once the alignment pins are installed you can tighten the crankcase bolts down and then install the cylinder.

I thought I got a picture of the ring compressor but I did not. I will get a picture and post it here.
 
Since I know that this saw lives at about 3'00 ft elevation and goes higher up to cut, I did a few upgrades to this saw.

I upgraded the electronic ignition in this 009 to a 6 degree timing advance unit. It required a flywheel change as well.

The advanced timing module is on the right.

The advanced timing flywheel is on the right in the second picture.

I replced the aftermarket spark plug boot with OEM when I replaced the spark plug wire.
DSCF4809.webp
DSCF4815.webp
DSCF4812.webp
 
Now time for the intake.

Inspect the Reed Plate and make sure there is not debris holding it open and that the pedal is not cracked at the rivets.

Over-reving a reed valve engine will break the reed. The metal "tongue" sticking up in this picture keeps the reed from over flexing.
DSCF4808.webp
 
Trim the crankcase gasket and install a new reed plate gasket and then the reed plate. The flat side goes towards the flywheel. It will fit 180 backwards but the throttle shaft will not rotate.


My Orange screw driver handle is pointing at the impulse hole. This picks up the negative and positive pressure in the lower crankcase. The fluctuation of pressure is what make the fuel pump inside the carburetor work.
DSCF4826.webp
 
Again, since I know that this saw lives at about 3'00 ft elevation and goes higher up to cut, I did a few upgrades to this saw.


Here is upgrade #2.

A fully adjustable carburetor.

The one on the left is the fixed high speed jet carburetor. You cannot adjust the high speed. When you get above 5,000 elevation, you really notice it in a saw this small.

The one on the right is the adjustable carb. The screw driver handle is pointing at the area the extra screw would be.

I cleaned and rebuilt it. I was going to do a pictorial on it but taking pictures of something shiney and smaller than a golfball does not work real well, even using the "Flower" setting on my camera.
DSCF4806.webp
DSCF4807.webp
 
Here is the fuel tank vent.

When fuel is pulled out of the tank by the carburetor, air has to be allowed in so a vacuum is not created inside the tank.

There is a set screw inside the line about 3/8" from the nipple. I held this up to the light so you can see the set screw. To big of screw or to small of line and you will create a vacuum in the tank.


The symptoms are that the saw will run about 3-5 minutes and die like it is out of gas. You unscrew the cap (satifying the vacuum), see fuel and go :meh: and put the cap back on. You will choke it and it will start and run another 3-5 minutes. You will continue to do this until your throw the saw over the hill or take it to a dealership and they charge $125 for a fuel system rebuild and a new carburetor.

The bottom picture shows where the tank vent ends. it has a sponge on the end of the hose as well as a screw in the end of the tapered cut line. There is a metal cover you took off when you removed the crankcase bolt. it is time to put it back on to protect the sponge.
DSCF4824.webp
DSCF4825.webp
 
Install the front handle bar or the AV mount for the 010 or 011 handle assy at this time. There is a nut that is a bear to get to with the carburetor on.

Install the carburetor and the throttle rod or the throttle cable. Depends on what version you are working on.


If you not already done so, install the muffler. The older orange series uses lock tabs on the bolts, lock down the tabs after the bolts are tight.

Install the starter assy, after cleaning the mechnism. Don't forget about the throttle rod being in the way on the 009 series.
 
I noticed a few screws were missing on the muffler so it got replaced.


I looked for an 012 Pro muffler to install on this saw but I was out and they are NLA. The 012 Pro has a dual port muffler and would make this a true "009L Magnum". :D
DSCF4821.webp
DSCF4822.webp
 
Last edited:
Saw is all back together. I cleaned the chain brake assy and installed new chain bumpers. You can see these in Post #41 above and below the bar stud. These in one form or another are on almost all saws and are considered a consumable item. They are plastic and are designed to wear. Thier purpose in the world is to keep the chain lined up with the giude bar when the chain get a little loose. If you are constantly throwing chains, make sure yours are installed.

I also checked the chain catch. It's purpose in the world is to catch the chain if it comes off. It reduces the damage done to the saw and the operator. They are consumable parts.

I will post pics.
 
Last edited:
I installed a 14" bar and chain and ran the saw and did preliminary carburetor adjustments.

I know this saw is going to elevation so the customer will need to fine tune adjust it for his elevation and his cutting length of attachment.
DSCF4828.webp
DSCF4829.webp
 

Users who are viewing this thread

Back
Top Bottom