stihl 024 funny idle

[JONSSTIHL]

a little history on the saw. My brother in law got the saw for free from someone he works for. I checked it out. The saw doesn't appear to be abused and is in fairly good condition cosmetically and mechanically. It blew 175 psi on the compression test when warm. It ran fine as is except for a inconsistent idle so I put a new air filter, spark plug and a carb kit in the wt-194 it has in it.

now for the bad part, the funny idle is still there. I had a hell of a time tuning it. I finally got the idle where the chain wasn't spinning and set the H to 13,000 rpm. It idles a little high but as soon as the saw gets put down the idle drops to 2,000 rpm and it stalls. it also does the same thing when I let it idle and let the tip of the bar take the weight of the saw without touching the throttle.

I did a pressure and vacuum test and turned the crank and fiddled with the impulse line while conducting the tests and no leaks found.

any ideas.

 

[old-cat]

Pull the carb and clean it good. Check the gas filter.

 

[z71mike]

The in-tank fuel line may have a small slit.

 

[JONSSTIHL]

I'm thinking maybe intake boot but seems like an air leak would cause the engine to rev up not die. I pulled and pushed on the handle while doing the pressure and vacuum tests to attempt to replicate the conditions.

The carb has been completely disassembled and cleaned when I put the kit in. I even took out the welch plug because it seemed like not all three idle cicuit holes were shooting carb cleaner out but everything was clean under the welch plug and I was able to confirm a good spray of carb cleaner from each hole with the welch plug removed.

I will investigate the fuel line further but it did look good when I pulled and twisted it while I had the carb out. Is there a trick to changing the fuel filter with the fuel line being so short in the tank. I can pull the filter completely out of the tank on my 2153 but on this 024 I can't even get it close to the filler cap hole.

 

[old-cat]

I use a wire with a tight bend/hook to grab the line and stretch it out.

 

[HarleyT]

The old lines get gummy, stretch and collapse, and crap from them collects in the carb. Go through the fuel system completely and correctly....

 

[JONSSTIHL]

I figured I could stretch the line out to get the old filter off but I was thinking ahead at the part when the filter is no longer on the end of the line and the wire has nothing to grab onto to stretch the fuel line.

I guess it is just one of those fiddly jobs we all love to hate.

the inlet screen in the carb was not full of trash but it did have some kind of transparent film coating it that I noticed when I held it up to a light

 

[HarleyT]

Make sure the hole under the screen is clear.

 

[old-cat]

it did have some kind of transparent film coating it that I noticed when I held it up to a light

You will probably have to do an ultra sonic clean out of the carb

 

[chainsawman2011]

you need to replace the screen in carb. more than likely the film on the screen is ethanol goo gobbed up in there. I have had a couple of these older stihls. an 024 and an 028 recently that passed vacum test and did the same thing put in new seals and impulse lines and it fixed the problem they both run and idle perfect now.

 

[jbighump]

Goin through the same thig with a 024 thats on my bench right now...2 times through the ultrasonic cleaner and new seals and its a lot better but still not perfect....guess one more time wont hurt...

 

[Bilge Rat LT 20]

Does the 194 have the check valve flap thing in the main nozzle or a ck valve in the body that would affect the idle?

Small engines are touchy about everything being right when getting them to idle properly.
Keep looking, check everything, replace rubber parts.

I am chasing a slowly dying at idle 026 myself. Going to swap carbs next, if it is the carb i want to fix the old one. I want to see the offending part, problem.
Somebody built it, it can be fixed. It may take learning a few choice German phrases to convince it though.