Made a dumb mistake on a stihl 200T. can I get some input please ?

[Wonka]

I know im most likely the dumbest person here so I'll go ahead and prove it.

I have been trying to figure out what is wrong with my old MS-200T and I have a new carb ordered for it.
Today I pulled the muffler off to look at the piston and it was pristine.
But, like a dumb ***, I hit the bottom of the saw and side with some air from a blow gun on the compressor
before it dawned on me that I had the muffler off. I looked at the piston and saw some tiny specs of sawdust
on the piston skirt. I dont know if any got into the crankcase or not and I dont remember exactly what position the piston was in when I hit the saw with air.
This saw is near and dear to my heart and im getting my first experiences repairing them.
I have an old 038 AV Magnum that needs to be gone through when I get better at it.


So, is this something that I need to be worried about and requiring a complete teardown ?

Any input is appreciated.
Thanks

 

[av8or3]

I sure wouldn’t do it based on what you’ve said. You could probably just slap it back together and run it , and it would be fine. But, if it were mine I’d just rinse it out best as can be with fuel mix , shake it out and then put it together. It’ll be fine.

 

[Wonka]

I sure wouldn’t do it based on what you’ve said. You could probably just slap it back together and run it , and it would be fine. But, if it were mine I’d just rinse it out best as can be with fuel mix , shake it out and then put it together. It’ll be fine.

So are you saying to take the muffler off and pour mix in the exhaust port, shake the saw around and pour it out ?

 

[Wonka]

I have a 68 chevy with a roots blown small block in it. I can build and work on that kind of thing but
when it comes to 2 cycles, I'm a complete idiot. The guy who designed the 2 stroke deserves massive respect.
Im completely lost with 2 strokes.

 

[gurwald]

Take the cylinder off and rinse the crank case with 2stroke mixif you want to be sure, or just run it and hope for the best.

 

[av8or3]

Yep, but I believe he said he had the muffler off already. If indeed he saw “tiny specs of sawdust on the piston skirt” there’s nothing of consequence in there. As hard as we try to make the internals on these engines a sterile environment it’s just not in the cards. If you could see the debris I’ve dug out of old saws that should have crippled them you’d probably be surprised. I guess though that anything is possible, so you can take all apart now and look for trouble or take it apart later IF trouble should develop. If you think it out, you’ll be replacing or reusing the same parts in either case.

 

[Wonka]

Yep, but I believe he said he had the muffler off already. If indeed he saw “tiny specs of sawdust on the piston skirt” there’s nothing of consequence in there. As hard as we try to make the internals on these engines a sterile environment it’s just not in the cards. If you could see the debris I’ve dug out of old saws that should have crippled them you’d probably be surprised. I guess though that anything is possible, so you can take all apart now and look for trouble or take it apart later IF trouble should develop. If you think it out, you’ll be replacing or reusing the same parts in either case.

At my current level of experience, im not comfortable of doing a complete tear down. And I know me, id want to replace EVERYTHING with OEM Stihl parts. Im not a fan of using any aftermarket parts
on any of my saws. It appears the the OEM jug and piston is about $200. the seals, bearings and gaskets are low cost. I just don't think I want to do my first rebuild on my 200T. Thats a saw I dont
want to screw up. Its too hard and expensive to replace if you can even find one. Theres a crazy person on ebay with a restored 200T that looks like it just came off the assembly line and he
wants $1600 for it. Now that's crazy. But it sure does look nice.

 

[Duane(Pa)]

The crankcase isn't open to the exhaust port...

 

[av8or3]

The crankcase isn't open to the exhaust port...

There you go!I should have thought of that. I’m always a little late to the party. KISS

 

[huskyboy]

The crankcase isn't open to the exhaust port...

I’m surprised any of the other “experts” on the forum couldn’t figure that one out Duane. Lol

 

[ElevatorGuy]

@Lone Wolf what do you think?

 

[huskyboy]

Like Duane said... the exhaust port isn’t open to the crankcase, only the combustion chamber. Unless you’ve free ported the exhaust during the process of porting it and dropping the cylinder... which is a whole other topic and I won’t add to the confusion. His saw is factory stock I assume. The OP said that there were specs of dust on the skirt of the piston. This means the piston was in the up position closing off the port. The OP can just wipe the skirt off with a rag and hit it with WD40..... and run the hell out of it. If he’s really worried he can pull the sparkplug and take a peek with a light. Lol

 

[av8or3]

I’m surprised any of the other “experts” on the forum couldn’t figure that one out Duane. Lol

They’re prolly not watching

 

[Wonka]

Like Duane said... the exhaust port isn’t open to the crankcase, only the combustion chamber. Unless you’ve free ported the exhaust during the process of porting it and dropping the cylinder... which is a whole other topic and I won’t add to the confusion. His saw is factory stock I assume. The OP said that there were specs of dust on the skirt of the piston. This means the piston was in the up position closing off the port. The OP can just wipe the skirt off with a rag and hit it with WD40..... and run the hell out of it. If he’s really worried he can pull the sparkplug and take a peek with a light. Lol

I looked in the head spark plug port with a borescope and saw some small vertical scratches in the cylinder wall but nothing like I've seen on the web when someone runs straight gas in one.
I dont know if the light scratches are normal or not. Its a bone stock 200t. I bought it from craigslist a few years ago and im repairing the stuff the guy did wrong. It had the wrong fuel line on it and didn't have
the round vent thing that plugs into the top left of the inside of the handle. I have ordered a new vent and I just replaced the fuel line / vent line combo. The old line had a hole in it. I thought that might be the problem with the infamous 200t stalling / bogging problem but that was not the case. I watched a vid online of a guy taking a small welch plug out of the carb and filling the 2 tiny holes under that plug with glue to seal those ports off. When I did that ( at this time im thinking ive got nothing to loose ) the bone cold saw started on the first pull in the choke position and then ran for a few seconds and stalled. It restarts and then wants to rev up but Boggs and stalls. So the welch plug fix to block off the fuel pump piston passages did nothing to solve my problem. I ordered a new OEM Zama carb for it. If the carb doesn't fix the problem im thinking I should try to get to the dreaded impulse line to ck it. And if thats not the problem, im thinking crankcase seals. God im hoping not. I did do a compression test on it and it was a little over 150psi. I have no idea what its supposed to be but that seems like a lot for an old saw. Getting parts for Stihl saws right now is tough. Im usually told a 2 week wait from any dealer I talk to. I also did replace the gas cap in case it was leaking air there. The guy at the dealer said that there was no longer an O-ring for the gas cap and I had to buy a complete cap. I think that seems unlikely but whatever. He was however was kind enough to charge me $25 for the fuel line and $9 for a new filter. Im thinking I need to find a place online where you can buy OEM stihl parts.
I guess its also possible that the intake boot may be damaged. Can you test for leaks at the intake with spraying carb cleaner around the boot while the saw is running while listening for engine speed changes ?

 

[jk14]

Put the muffler back on and Send it.

 

[huskyboy]

You can definitely check for leaks by spraying brake cleaner around the intake boot while it’s running. Probably a carb problem though, those saws are notorious for that.

 

[Wonka]

Like Duane said... the exhaust port isn’t open to the crankcase, only the combustion chamber. Unless you’ve free ported the exhaust during the process of porting it and dropping the cylinder... which is a whole other topic and I won’t add to the confusion. His saw is factory stock I assume. The OP said that there were specs of dust on the skirt of the piston. This means the piston was in the up position closing off the port. The OP can just wipe the skirt off with a rag and hit it with WD40..... and run the hell out of it. If he’s really worried he can pull the sparkplug and take a peek with a light. Lol

you are right. I ran the piston from top to bottom and the bottom of the skirt never clears the exhaust port at the muffler. I will hose it down with wd40 and hope the carb fixes the problem.
I have not done any pressure / vacuum testing. Im a rookie with 2 strokes so im not jumping in feet first in fear of screwing up my 200t

 

[Wonka]

I really appreciate all the input and help !

 

[Wood Doctor]

You can definitely check for leaks by spraying brake cleaner around the intake boot while it’s running. Probably a carb problem though, those saws are notorious for that.

Agreed. Carb problems are common, but I recently ran into one that had thrown one of the piston pin's snap rings. That ruined the cylinder and the piston and left no compression. A complete top-end rebuild got her going again.

 

[Nutball]

You can definitely check for leaks by spraying brake cleaner around the intake boot while it’s running. Probably a carb problem though, those saws are notorious for that.

Maybe ether instead? I'd be afraid of getting brake cleaner on rubber.