Stihl 024 air leak

[spudulike]

From memory, I believe they both share the same rear handle. There are so many different variations of the 024, MS240, 026 and MS260 that you can swap many parts. I have worked on old 026s with old original carbs and the only way I could stabilize the idle some was to fit a later carb which resolved the issue.

Yes, you could swap the compensator covers out with flat ones but I really can't remember if I have in the past.

[ihatesaws]

Thanks.  Is it that you don't rate tillotson carbs very highly or you just haven't had any experience with the HU-136 in this saw?

[spudulike]

I have just worked on a number of 026s and when I have been through the whole saw and the idle isn't good plus the carb is old, I have found MS260 carbs fix the idle issue. 

Basic rule of thumb, if you can't dial a carb in within 2 mins, it needs sorting.

[ihatesaws]

I bought a used wte-1 from america but it will surely take a while to arrive.  I went to start the 024 today  but it wouldn't start properly.  This is the one with the new spark plug and when I tested it I couldn't get a spark.  I put the 024s plug in and the saw started.  What could be causing the saw to damage the spark plugs?  The coil gap is a bit big at 0.3mm but I can't get it any smaller. 

Edited April 19, 2023 by ihatesaws

[spudulike]

One issue with this model is that the HT lead can rub on the top AV mount ( the one by the air box) and start arcing on it so it starts cutting out.

The machine shouldn't knock out sparkplugs, I once had a FS1E that had a bad helicoil and it didn't transfer heat well and it would melt the plugs but not seen it on a saw. I have seen loose electrodes in Rockwood plugs but a real Bosch or NGK should last for years.

[ihatesaws]

20 hours ago, spudulike said:

One issue with this model is that the HT lead can rub on the top AV mount ( the one by the air box) and start arcing on it so it starts cutting out.

 

I have that damage as well.  I've put some tape around it.  The black wire to the on switch is bare in a patch as well.  I got the two plugs working again heating them with a torch and rubbing them with a wire brush.  They were fouled with oil?  When I assembled the saw I put grease on all the bearings and I coated the inside of the cylinder with oil before putting the piston back in.  Could some of that stuff be coming up on to the plugs?  They were wet and blackish when I took them out of the 024.  After a spell in the ms290 they turn coffee brown.

[pleasant]

Whatever you use to lubricate the lower moving parts of your engine upon re-assembly, will be scavenged when the engine is hot and running, and will become part of your fuel mix vapour for a period until it is effectively 'burnt off'

Edited April 20, 2023 by pleasant

[spudulike]

Black means they are running rich and they shouldn't be fouling up like that unless the carb is well out.

Tan, coffee colour is about right and this will come by running a saw flat out in larger cuts for a while.

 

[Dfc548]

@ihatesaws please continue to work on this issue! I just found the forum and made an account specifically for this issue. I have two 024s with the identical issue as yours. I have replaced both crank seals, coil, plug, new carburetors on both. Pressure and vacuum tested both saws and have no leaks what-so-ever, compression in both saws are 150-155, but when idling they are sporadic and die, when you tilt the saw to the sprocket side it will increase rpm’s and will typically die when you set the saw back down. 

[ihatesaws]

The adventure continues.  I thought this video had some good tips on carburetor fault finding:

https://youtu.be/_4K6dBQTeek

In particular the throttle butterfly was not in the correct position on the wt-194.  Earlier in the thread I tested if air was entering through the throttle shaft and if I could block it.  I set it correctly but it didn't make the saw work any better.  I thought that a defective check valve allowing air into metering chamber would produce an irregular idle but my check valve holds a vacuum successfully.

 

I finally got the second hand WTE-1.  The compensator lid was easily swapped with a WT lid.  The WTE however has a big chunk of metal around the H screw which prevents the carb from sliding into the tank housing.  I spent quite some time with a dremel grinding away plastic so that it would fit.  I then had to enlarge the holes in the plastic for both L and H screws so that I could adjust them.  I just tested it on the 024 sofar.  If I want to do it on the 024S then I'll have to similarly modify its tank housing. 

 

The saw started on half-throttle and I could rev it up but releasing the throttle it died immediately regardless of the position of the L screw.  It was only when I turned the LA almost completely in that it would idle.  I got a max rpm of around 3200 at 1 turn out on the L.  I set the L then at 1 1/4 turns out.  My overall impression is that the idle is more stable.  However I couldn't rev up the saw but very rarely.  It wanted to stall when I pressed the throttle most of the time.  Then suddenly without changing the H screw it would rev up but not for very long.  I'm presuming some kind of fuel restriction issue.  I took the carb apart.  Gaskets very sticky to remove and I should really put a carb kit into it but they are dear compared to WT kits and not available locally.  The pump diaphragm looks okay, the mesh filter looks clean but I'm having trouble removing it to make sure.  The metering diaphragm is a bit crackly.  I'm soaking it in brake fluid to regenerate it.  I don't have the walbro gauge for setting the height of the metering lever for a wte carb.  Is there some improvisation?  I tried to remove the lever but the screw head was strange or damaged.  It's worse now and I think I'll have to cut a slot in it to remove it.  Some guy online complained about removing the screw on this carb as well.  He said loctite was used.