Stihl 025.....what would you guys do?

[flyboy]

I bought a Stihl 025 from a Stihl sales guy. It was his personal saw that he could not get to run right.

Basically it would run nice and strong then it would cut out all of a sudden. It is not as strong as my muffler modded 026, but it did pull just fine in the cut.

It has the low adjust only carb (walbro wt) and it was set very rich. I pulled the carb apart and found a BB sized hunk of Dirko in it (my guess is the Dirko was blocking a passage intermittently).

I was all set to press it back into service when I decided to do a compression test. It is only getting 135psi (I checked my 026 with the same tester for sanity....165psi). The piston skirts look new. The top of the piston has some slight pitting on one side. The entire cylinder is sparkly but shows no sign of scoring.

There is evidence that the seals were recently replaced. Pressure and vac tests pass perfectly. The bearings feel perfect and make zero noise. I was told that the saw has all new fuel lines and they all look perfect.

I'd hate to replace a perfectly good piston/rings, but the compression isn't quite what my other saws have. Maybe just doing rings and getting the saw split in 2 for a closer look is in order.

Where can I buy Dirko and how much is it? Can I just use copper permetex? Can I get the rings anywhere for a reasonable (sub $15) price?

What would you do? My gut feel is to put it back together and run it.

 

[flyboy]

Bump.......

 

[MS460WOODCHUCK]

I would put it back together and run it if it were mine.

 

[Saw Dr.]

If you already have an 026, you're probably only going to use the 025 once in a while. If it idles good at 135 PSI, I'd run it. No sense in taking the chance of creating an air leak in a tight engine. Most of those don't go much over 150 PSI anyway, unless there is alot of carbon on things.

 

[wrooster]

run it. that 135psi compression is fine for an 021/023/025, it will work great.

if not, see
http://www.arboristsite.com/showthread.php?t=129434

jim aka the wrooster

 

[flyboy]

If you already have an 026, you're probably only going to use the 025 once in a while. If it idles good at 135 PSI, I'd run it. No sense in taking the chance of creating an air leak in a tight engine. Most of those don't go much over 150 PSI anyway, unless there is alot of carbon on things.

The saw is not for me. I am fixing it up for a friend who needs a cheap saw to clean up after the power company. He only needs the saw a couple times a year. When I sell it to him, it will come with a 6 month warranty and a 6 pack of stihl synthetic 2 stroke oil. Not bad for a $125 in my mind.

 

[Stihlofadeal64]

If it idles smoothly at 135psi I say run it unless you have the itch to tear into it and go through it. An aftermarket piston and rings could be had for around $30.00 (that is if you would use them). I've been through quite a few 025's and they seem to be fine for the engine size. In relation to Dirko, I believe you could simply use Ultra Grey sealant and be fine. Happy Sawing!

 

[sdb153]

I just bought some Dirko from this guy last week.

http://www.corradoparts.com/Gaskets-Dirko_High_Temperature_High_Performance_Sealer.html

 

[flyboy]

If it idles smoothly at 135psi I say run it unless you have the itch to tear into it and go through it. An aftermarket piston and rings could be had for around $30.00 (that is if you would use them). I've been through quite a few 025's and they seem to be fine for the engine size. In relation to Dirko, I believe you could simply use Ultra Grey sealant and be fine. Happy Sawing!

It idles fine for about 1 minute and then the RPMs start to drop off, ultimately stalling the engine. I have not set the carb yet, so I think the plug may be loading up.



How do you set the mixture on these 1 screw (low only) carbs?

 

[JasonBmac]

With a Lo needle only, you simply tune for reliable idle and acceleration. Here's how I do it.

Warm the saw up... Make a few cuts. Now, get a screwdriver on the Lo needle.

Slowly turn the Lo needle out. The saw should slow, may well stop. This confirms you Lo is on the rich side.

Now slowly turn the Lo needle in. The idle will smooth out and speed up as you go. It will eventually reach a peak, and will drop off and quit if you go further. Open the needle just to the rich side of that peak.

Now, crack the throttle. If the saw sucks air and bogs, open the Lo needle slightly. If it burbles and coughs smoke, close it slightly. Adjust until it will idle for at least 30 seconds and still accelerate cleanly.

Do not attempt to adjust WOT mixture with the Lo needle. If WOT is sick rich (It should generally be "fairly" rich), open the carb, and lower the metering lever a couple thou at a time. If it 4 strokes WOT no load, but 2cycles in the cut without bogging or showing lean signs, it's good.

J

 

[Fish]

Got an 025 real cheap once, would start and run pretty good, but every now and again, it would shut down as if you flipped the off switch. Would
start back up and run some more, shut down every now and then, no
predictable time.
Replaced the coil, had a good running saw after that.

 

[flyboy]

Well it is running very strong. I had to rebuild the carb. I found K10 WAT kits on ebay (Walbro brand even) for about $5 shipped. The metering gasket was shot. Between that and the dirko in the carb.....that was it.

I do have to raise the lever some. It is pulling 15k rpm right now.....way lean.

 

[Stihlofadeal64]

Well it is running very strong. I had to rebuild the carb. I found K10 WAT kits on ebay (Walbro brand even) for about $5 shipped. The metering gasket was shot. Between that and the dirko in the carb.....that was it.

I do have to raise the lever some. It is pulling 15k rpm right now.....way lean.

Tune it out to 14k max, that is the Stihl spec. It looks like everything else will be fine. Happy Sawing