Stihl 024AV will not run!!!

[borat]

I've been working on an old Stihl 024AV chainsaw for the last couple of days. I've installed the K10-WAT kit, completely cleaned the carb, inspected the fuel lines, set mixture screws at 1 turn (and numerous other settings) but it still will not run.


I printed out a .pdf file to make myself a metering lever measuring tool. Set the lever midway at .065", put everything back together and gave it a shot. Saw fires up but runs out of gas. Pulled the carb again and set the lever even higher to pass more fuel, with the same results.

The carb has fuel in it when I disassemble it but, for some reason, it doesn't seem to feed it through the jets. I've had the carb apart numerous times and verified that every orifice and passage is clear. Spark is excellent. I know it's a fuel starvation problem because if I pour a bit of gas into the throat of the carb, the saw will fire up and run until that fuel burns off.

I've had the carb off and cleaned many times with no positive results. I'm beginning to wonder if it's a fuel supply pressure problem? I know the fuel line is passing fuel inton the carb but I'm wondering if the engine pulse pressure might be weak and cannot drive the fuel pump diaphragm sufficiently to keep adequate fuel pressure in the carb? When the saw fires up it runs for a few seconds on idle and peters out. It will not take throttle. Obviously a fuel issue.

Other things I've checked:

Compression - 125 psi
Fuel pick up in tank - clean
Exhaust port, spark arrester and muffler all clean
Fuel line clear, engine pulse line clear

I pulled the saw apart again enough to inspect the pulse line and it's in good shape. I put a cork in the carb boot and blew compressed air through the pulse line. It blew the cork a good 25 feet away. From that, I would assume that the pulse pressure and line is good. Nonetheless, the saw won't run.

I pulled the carb again and went through every passage and jet. I pulled the mixture screws and blew compressed air through the screw holes blocking the two small holes in the fuel accumulation area near the metering lever to force air through the jets. I also blew compressed air through the two small holes in the fuel accumulation area. Everything is clear. Still, the saw will not run.

If I put my finger over the carb throat and pull the start rope a few times, the carb pulls enough fuel into the venturi to allow the saw to start and run briefly but the carb will not sustain a running engine either idling or at full throttle.

I've tried a number of different settings for the metering lever from low to high with no difference. I've tried numerous settings of the mixture screws. Fuel gathers in the carb but does not seem to make it through to the jets. Which is strange because if I block the carb throat and spin the engine, fuel will come through the jets into the venturi.

This is the most baffling carb/fuel issue I've come across. Any ideas?

 

[angelo c]

I'ld like to check the Impulse line with a guage to see if it will hold vaccuum. Maybe tank pressure as well. Is the tank vent holding. Maybe a known carb to verify but sounds like a fuel delivery issue so far. Ethanol is causing many "mystery" carb issues that seem to be only fixed by replacement.
Keep us posted. Some of the big wrenches will be along soon with some other ideas. They are still at Saturday night church...

A

 

[borat]

For the life of me, I can't seem to figure this one out. I do a fair amount of wrenching and I'm very familiar with two cycle engines although, diaphragm carbs are NOT my specialty.

I bought this saw used last year and gave it to a friend who had his saw stolen. He used it a bit then left it unused for over a year. He brought it out to cut some wood and it wouldn't run at all. I've since spent many hours trying to figure out what the problem is and have gotten nowhere.

I do all of my own small engine work and usually get things running. This saw is more of a challenge than I had bargained for. Not familiar with Stihl saws. I personally own two Jonsereds saws that have been bullet proof for over 25 years. I know Stihl make good products and even these old saw are worth fixing. However, I'm up against a wall with this one.

One thing I noticed when I removed the carb, I didn't see a gasket between the carb and carb boot. Is that normal? When I pull the carb, there's a metal ring around the carb boot and a small metal insert inside the carb boot. That's all.

I'd sure like to get this thing running for the guy I gave it to.

 

[roostersgt]

You need to ponder the possibility that carb kits simply DO NOT solve all carb related problems. A lot of folks have gotten lucky that their problems were simple dried out rubber carb diaphragms and gaskets. I have run into this in the past ans was as frustrated as you are. Change out the dang carb with a new OEM one from Ebay. My problem went away just that quickly. Some carbs just get worn out, or the seats become boogered beyond usefulness. The carbs have many metal to metal parts and the alloys can corrode from water and fuel.

 

[borat]

You need to ponder the possibility that carb kits simply DO NOT solve all carb related problems. A lot of folks have gotten lucky that their problems were simple dried out rubber carb diaphragms and gaskets. I have run into this in the past ans was as frustrated as you are. Change out the dang carb with a new OEM one from Ebay. My problem went away just that quickly. Some carbs just get worn out, or the seats become boogered beyond usefulness. The carbs have many metal to metal parts and the alloys can corrode from water and fuel.

Thanks for the reply.

Rest assured that I've been thinking hard about getting a carb for it. The thing is, the saw was bought dirt cheap $40.00. Not too sure if I want to spend more for a carb than I did for the saw. Either way, if I do go for a carb, would it be a Walbro model WT-110-318?

The reason I ask is that when I look at diagrams for the above model carb, it shows it with parts that are not the same as the carb I'm working with. I. e. primer bulb etc.

 

[DG2244]

You stated your compression was 125psi. That is way to low for me. That saw should be 150+ psi.

 

[WoodChuck'r]

Buy a brand new 460. Problem solved!

:hmm3grin2orange:

 

[borat]

You stated your compression was 125psi. That is way to low for me. That saw should be 150+ psi.

Yeah, the more I find out, the less likely I'm about to put more money into this thing. It's becoming abundantly clear that this saw is probably shot. I see carbs listed on ebay for $90.00. Not going to happen. I've seen used saws (Stihl, Husqvarna, Jonsereds) in pretty good shape for a couple hun. Might as well file this one under "G".

Too bad. I like bringing old things back to life.........

 

[borat]

Buy a brand new 460. Problem solved!

:hmm3grin2orange:

I have two good Jonsereds saws. A 630 and a 670. I also own a little Echo CS346, which is a great lightweight.

The Stihl isn't for me. I purchased it used to give to a friend who had his saw stolen. Now that I know the 024 is likely junk, I'm looking at replacing it with another used (hopefully in better condition) saw to replace it. I see a local ad for an 034 in real good shape/low hours. Not an 034S. I might be able to get it for around $200.00.

Any comments on that particular saw? Will the bar/chain from the 024 fit on an 034?

 

[roostersgt]

The 024 is a good saw and certainly worth another carb. This one is from a reputable guy and is $25. If you only have to put $100 total into the saw, you're way ahead of the game. That saw would put all new $200 saws to shame and would definitely outlast them. Wouldn't worry about the 125lb either. Probably a screwy gauge. If it pops with gas poured down it, it's fine.

STIHL 024 CHAINSAW CARBURETOR | eBay

 

[borat]

Thanks for your input. I'll think it over. Personally, I like the size of the 024. It's a fair amount lighter than my Jonsereds saws. However, as I've said, it's not for me but I might use it on occasion.

Will the bar/chain from the 024 fit on an 034? If so, I might just go for the 034.

 

[angelo c]

Borat,
Having your location posted might help some neighborly fellow that might have an 024 carb thats known to operate that might just send it up to you so you could confirm your issue. been known to happen a few times on this forum amogst friends. You'ld be surprised how inclusive of a fellowship this group is. Some of the finest examples of the American Way you'll ever find, and I say that knowing many members are from other Countries, and they would help too !!!

 

[a. palmer jr.]

In answer to one of your questions: Yes, it is common to not have a gasket under the carb when a boot is used. The lip of the boot seals the carb and there's no pulse hole because the pulse comes in through a separate line. I would look carefully at that pulse hose and see if it's cracked, broken, or unhooked at one end. The saw is worth fixing and it probably won't take a new carburetor to fix it. I would check that carb out to make sure the inlet lever is set at the correct height also.

 

[borat]

In answer to one of your questions: Yes, it is common to not have a gasket under the carb when a boot is used. The lip of the boot seals the carb and there's no pulse hole because the pulse comes in through a separate line. I would look carefully at that pulse hose and see if it's cracked, broken, or unhooked at one end. The saw is worth fixing and it probably won't take a new carburetor to fix it. I would check that carb out to make sure the inlet lever is set at the correct height also.

Thanks for the info.

I've thoroughly examined the pulse hose and it's in good shape. Fuel does get to the carb but it doesn't seem to get to the jets. I'm going to give the carb another good going over, and try re-setting the metering lever again. Like I've said, if I cover the carb throat with my finger and spin the engine, it pulls fuel into the venturi and engine. Remove my finger and pull start and it fires up??? So, from that, I'm lead to believe that there's insufficient pressure being created by either the fuel pump or the metering diaphragm isn't exerting sufficient force on the fuel intake needle.

Visually, the carb looks new. Being a solid piece of aluminum with a bunch of holes drilled in it and minimal moving parts, I don't know what can go wrong with these things to cause replacement? I know that they apparently do.

Either way, I'm going to go over everything one more time.

 

[Fish]

Disassemble the carb again, and remove the needle/lever/spring and hold up to a light, then blow out that passage, and hold it up again and visually verify that the passage is open.

Reassemble.

Then reach into the tank and give the fuel line a pinch, with age and the newer fuels, the fuel line gets soft and gummy, and may be your problem.

Also, the cork test you did may have blown out your seals.

 

[a. palmer jr.]

Thanks for the info.

I've thoroughly examined the pulse hose and it's in good shape. Fuel does get to the carb but it doesn't seem to get to the jets. I'm going to give the carb another good going over, and try re-setting the metering lever again. Like I've said, if I cover the carb throat with my finger and spin the engine, it pulls fuel into the venturi and engine. Remove my finger and pull start and it fires up??? So, from that, I'm lead to believe that there's insufficient pressure being created by either the fuel pump or the metering diaphragm isn't exerting sufficient force on the fuel intake needle.

Visually, the carb looks new. Being a solid piece of aluminum with a bunch of holes drilled in it and minimal moving parts, I don't know what can go wrong with these things to cause replacement? I know that they apparently do.

Either way, I'm going to go over everything one more time.

If I were you I would take the H and L screws out again and squirt a little carb cleaner in them after you take it apart. It might still have a piece of dirt somewhere in it. Did you take compressed air and blow into those holes last time you cleaned it? I probably would do that also, but only do it when the carb's all apart to keep from damaging anything. I assume you've already adjusted it every which way you can. Sometimes these things do well with only one turn or less while others require one and a half or even more.

 

[borat]

Carb is thoroughly clean. I sprayed WD40 through all the holes/galleries/jets then blew out with compressed air. I adjusted the metering lever to allow more fuel flow. I made a gasket to go between the carb and boot just in case it was sucking air. I tested the carb by puffing bits of air through the pulse line and watched as tiny spritz's of gasoline blew past the needle valve when I depressed the metering lever. I put the gasket and metering diaphragm on and tested it for contact with the metering lever. All was good. Put the mixture screws back in at one turn. I even put a bit of heat shrink on the pulse fitting to make a tighter fit in the pulse hose then installed the carb. No change. If I put my finger over the carb throat, it sucks enough fuel to fire the saw and run a bit, but soon stops.

I've come to the painful conclusion that there might be a crankcase leak or too much blow by in the cylinder effecting crankcase pressure pulses.

I'm pretty much done with this saw. Forty bucks for forty minutes! Can't really whine too much. As they say, you get what you pay for. The upside is that I have another buddy with an 024 AV. He can have this one for parts.

 

[Fish]

So you removed the needle/lever/spring?

 

[Fish]

Checked the fuel line down in the tank?

If it is real soft and gummy it can collapse and not allow the saw to run.

 

[borat]

Yes to both questions.

Fuel gets to the carb but it seems there's not enough engine vacuum to pull it into the cylinder. If I block the carb throat, it will pull fuel but not without assistance. I suspect the saw is just shot. Either crank seals or too much blow by. Either way, I'm not putting any money into it.

Thanks to everyone for your help.

Got a line on an 034. Will the bar/chain from the 024 fit on an 034?