Stihl 036 wont rev

[AdkStihl]

Back at the shop, the head tech takes the carb off and found the jets plugged.  Poked out the jets with a thin wire.  The fuel line held pressure fine, but showed a wet spot near the attachment of the fuel filter - a micro pin hole that would surely only get worse.  New fuel line, blast the jets out, reassemble and it ran fine all week.

From a repair standpoint, that carb is cheaper to replace than it is to clean & or rebuild.
Those carbs, brand new, at your dealer should cost no more than $29

He poked the jets out with a wire?......Err...Ummm....that woulda been my last visit to that shop.

[beenthere]

He poked the jets out with a wire?......Err...Ummm....that woulda been my last visit to that shop.

My thoughts too...  ;)

[ancjr]

Thanks!  I'd never had known if you guys hadn't said something.  Sorry I wasn't more helpful.

Now we return to your regularly scheduled programing.  :)

[ZeroJunk]

Thanks!  I'd never had known if you guys hadn't said something.  Sorry I wasn't more helpful.

Now we return to your regularly scheduled programing. 

There is nothing wrong with cleaning a jet out with a wire or torch cleaner if you can get to it. It's been done ever since somebody invented carburetors.

[Frank T]

Update
I got the Fuel line and carb kit yesterday. Put the fuel line on and it did the same thing. Started but died when you hit the gas.
Took the carb apart and found the Diaphragm (Moves the needle and seat) completely packed with crap. I cleaned the rest of the carb, replaced all the parts. put it on the saw and it started and ran good when I hit gas! After the dance of joy, I took it out and cut a piece of wood with it. It ran OK but was starving for fuel or air.

I tried adjusting the carb like a 4 stroke carb but was unsuccessful. Does anyone have a sequence for adjusting the idle speed screw and the high / low mixture screws. Which to I adjust first idle or High speed cutting?

Example: on a Holley carb for a car you adjust the idle mixture screws out 1.5 turns, Start the car, then turn the idle speed screw down to the RPM where you get the highest manifold vacuum (12-18hg @ 600-800 rpm), then turn the idle mixture screws (in or out) until they dont affect the vacuum and RPM. The Idle speed screw adjusts the vacuum and the mixture screws adjust the fuel to that vacuum. If the speed screw is open too much the carb will be pulling fuel from the wrong circuit and the mixture screws do nothing.

I tried to use the same method (at idle) but the saw ended up dying and fouling the plug.
1. What is the process for the 3 adjustment screws?
2. Do both mixture screws need to be adjusted for both speeds or does one effect idle and one effect high speed?
3. Does the idle speed screw effect high speed cutting?
4. Is the idle speed done first or the high speed cutting done first?

Thanks
Frank T

[ZeroJunk]

Adjust your idle first. Adjust to maximum RPM and then richen it up a little, maybe a 1/8 turn or so. At Maximum RPM idle mixture they will usually stumble when you open the throttle. They need to be a little on the rich side to handle the sudden increase in air before the high speed jet takes over. So, tune for the transition. High speed jet has nothing to do with idle. Idle jets run all the time but have a pretty negligible effect on high speed tuning.

Then tune your high speed so that it four strokes no load and two strokes in the cut. Unless you are really used to tuning saws you are better off with a tach. Also, keep in mind that fuel will pool up in the crankcase to some extent. So, they will lean out after being in use for a few minutes. If you just tune them cold they can end up too lean.

[Frank T]

Zero Junk
First, Thanks for the response but Im not sure If I understand what to do. Again Ive never done this before on a saw so any details you can throw at me would be helpful.
Here is what I tried:
Started the saw with all three adjustment screws 2 turns backed out.
Screwed the idle speed screw out and all that did was drop the RPM. So I screwed it in and the RPMs went up way up, like I could cut wood at idle. That seemed wrong. So I turned the screw out to a good idle point and started adjusting the low mixture screw. I went as far as the speed screw bottomed out and the low mixture screw about a 1/4 from bottomed out and the saw was still idling, but poorly. When I rev'd the motor it was blowing alot of crap out the exhaust. That seemed wrong also. I screwed around with the idle speed screw and Low mixture screw until the saw stalled and fouled the plug again. I never touched the high speed mixture screw.

Am I correct in the following definitions?
Idle speed screw: larger screw above the two smaller screws. This screw adjusts the 'at rest' setting on the throttle plate and limits the air going to the cylinder.
Low mixture screw: adjusts the flow of fuel at idle depending on the size of the opening created when turning the screw in or out. The more you turn it out the more fuel gets dumped into the carb
High mixture screw: adjusts the flow of fuel for higher RPMs. The flow depends on the size of the opening created when turning the screw in or out. The more you turn the screw out, the more fuel that can potentially be dumped in the carb. Acts like an adjustable jet.

What do you mean by "four strokes no load and two strokes in the cut". I have a tach on my meter but I dont know what to hook it up to on this saw. Nor do I know how it would interpret a 1 cylinder 2 stroke (It has settings for 4/6/8 cyl 4- stroke engines).

Again thanks in advance for any advice

Frank T

[Frank T]

Just found this video on youtube...
Gonna try adjusting my saw this way tomorrow

http://www.youtube.com/watch?v=D7mnQKIVMXs

[ZeroJunk]

When you are talking about the idle speed being too high are you sure that you pulled the trigger after it started to get the linkage to drop it off high idle ?