Stihl MS194T may have run without mix

[vtwinjunkie]

Such a dodo...

In a rush to help a neighbor at dusk (getting dark), I grabbed by chainsaw, bar oil and gas can (that I always have mix for the saws in) and helped a neighbor cut up a huge pine to clear his drive.

My saw did great as always, half way through I filled it with the gas that was in my can and after the work was done I went home and all seemed fine.

fast forward a few weeks and I go to fill up a backpack leaf blower with the same gas can and noticed the gas was not the right color. Investigating further it looked like it was not mix. Thinking back to the chainsaw and dumping the gas out of that wich was half full at the time, it was the same clear, yellowish gas color......ooooops!

immediately mixed up some new gas and dumped it in. fired it up and it runs normal.


Im concerned that I may have caused damage but wont know until I tear into it. My thinking is Id rather proactively check it out (maybe only need to replace rings and piston) now rather than keep running it and maybe have more to replace later.


couple questions:

1. How screwed am I?
2. Anyone have a service manual PDF for the 194T?
3. Best place to get Stihl genuine parts?

Thanks all.

 

[WI_Hedgehog]

It's a STIHL, it won't run any different.

I'd pull the muffler off and and intake boot off and check for scoring, do a pressure and vacuum check, check compression, and then determine what to do because it may be fine (but I'm not a saw mechanic).

 

[ZeroJunk]

If it runs normal leave it alone.

 

[ZinTrees]

it'll be fine, mine had half a tank of diesel ran through it before anyone noticed... you'd think the smoke was a dead giveaway, no?

pour it out, refill with normal mix gas and forget it ever happened, as long as it still has compression and runs good

 

[vtwinjunkie]

Thanks all. Whats the

It's a STIHL, it won't run any different.

I'd pull the muffler off and and intake boot off and check for scoring, do a pressure and vacuum check, check compression, and then determine what to do because it may be fine (but I'm not a saw mechanic).

Not sure what you mean by do a pressure and vacuum check. can you elaborate? Maybe thats in the manual that I dont have yet?

What compression are these supposed to be at? I can easily check that.

Coming from the auto and dirtbike/motorcycle world so I have some basic knowledge.

 

[WI_Hedgehog]

Thanks all. Whats the

Not sure what you mean by do a pressure and vacuum check. can you elaborate? Maybe thats in the manual that I dont have yet?

What compression are these supposed to be at? I can easily check that.

Coming from the auto and dirtbike/motorcycle world so I have some basic knowledge.

These are pretty standard tests on a 2-stroke and not hard to do. If the saw shed a little metal and it found a seal the P/V test should show if a problem exists. I am not an expert, just learned a few things from the guys here, which is great because 2-strokes were a near complete mystery for years. Shop manuals describe the procedure, and once you do one the rest are comparatively easy. Several threads here show how to do it on the cheap and easy. When you do this the first time make sure your test equipment isn't the source of an apparent leak, I had created a bad seal my first time, and also had a dirty decompression valve (I removed it and blocked the hole with a finger, all tested fine, so I cleaned the valve and then it tested good).

Pressure check is where the saw case/housing is sealed and about 7.5# of pressure is applied. Soap water is put on the seals to see if air is leaking past them.

Vacuum is the same without the soap water, the case should hold the vacuum reading specified in the shop manual.

Compression requires a valved small engine tester, 135psi or more seems to be "good."

 

[vtwinjunkie]

These are pretty standard tests on a 2-stroke and not hard to do. If the saw shed a little metal and it found a seal the P/V test should show if a problem exists. I am not an expert, just learned a few things from the guys here, which is great because 2-strokes were a near complete mystery for years. Shop manuals describe the procedure, and once you do one the rest are comparatively easy. Several threads here show how to do it on the cheap and easy. When you do this the first time make sure your test equipment isn't the source of an apparent leak, I had created a bad seal my first time, and also had a dirty decompression valve (I removed it and blocked the hole with a finger, all tested fine, so I cleaned the valve and then it tested good).

Pressure check is where the saw case/housing is sealed and about 7.5# of pressure is applied. Soap water is put on the seals to see if air is leaking past them.

Vacuum is the same without the soap water, the case should hold the vacuum reading specified in the shop manual.

Compression requires a valved small engine tester, 135psi or more seems to be "good."

Ahh, a leakdown test. Done that many times on dirtbikes over the years. Thanks!

Id definitely like to find a service manual for this though....anyone know if Stihl makes them?

 

[ZinTrees]

Ahh, a leakdown test. Done that many times on dirtbikes over the years. Thanks!

Id definitely like to find a service manual for this though....anyone know if Stihl makes them?

search up the "beg for manuals" thread, there's a guy over there with manuals to everything, I'm pretty sure he has an I.P.L for the international space station!

 

[DND 9000]

You know that it is against the copyright law to share such things

 

[stihltech]

When you say Leakdown test, I think of using pressure on a 4 stroke to test rings and valves. Pressure and vacuum test are not the same on a 2 stroke. Maybe we are calling the operation by 2 different names?