201TC spark plugs

EasternArborist · Mar 7, 2023

Ive been going through spark plugs like crazy, when I replace them the saw works perfectly. Im replacing the plug 2 times a month, I suppose its probably ethanol in the fuel? I thought at first it was a bad batch of plugs but am on the second order. Ive never had to add anything to the mix gas since I use it up so fast but this is a pain in the ass. All the other medium/ large saws (husky) aren't having any issues, any ideas?

Reach · Mar 7, 2023

I have never heard of that problem, Ethanol in the fuel should not burn up spark plugs, unless you are running really lean. That could make enough heat to burn up the plugs, maybe you should have the shop take a look at the saw and make sure it is properly tuned. If you are running lean, you might have higher engine speeds than usual, you will also have higher engine temperatures, and run the risk of burning up the rest of the engine as well.

Is that saw stock, or has it been modified in anyway? That can make a difference as well.

Are you able to post a couple pictures of one or more of the bad spark plugs? Especially the tip, where it sits inside the engine? It is possible to read the tip of a spark plug and see how the engine is running, and whether the mix is in the right ballpark or not.

EasternArborist · Mar 8, 2023

The saw is stock, it doesn't sound like its running hot, Ill take some pix this morning when I change out the plug again, thanks for reply.

EasternArborist · Mar 8, 2023

EasternArborist · Mar 8, 2023

This plug was only in for 2 weeks

Reach · Mar 8, 2023

What is the saw doing when you feel the need to replace the spark plug? From the pictures I see, that plug looks just fine. If anything, the saw might be running a little rich, but probably not enough to hurt anything.

EasternArborist · Mar 8, 2023

A few times when it was wide open it would make a pop sound then shut right down and not restart until I replaced the plug. yesterday I went to cold start it , the saw tried to start but wouldn’t rev up , just ran for a few seconds then quit and wouldn’t restart. It’s about 3 years old and a daily driver maybe it’s just used up ?

Reach · Mar 8, 2023

That could be an ignition coil issue, but more likely that sounds to me like a clogged spark arrestor screen in the muffler. Climbing saws frequently don’t run hard enough to clear themselves out, and if you leave your saw idle a lot when you are working, it will really clog up in a hurry. I would start by disassembling the muffler and checking the screen and exhaust ports.

evo · Mar 8, 2023

I’ve had the little post fail, where it would rattle around and close the gap. I got very lucky as when I took it apart it fell right out.
Perhaps piston slapping?
But the only other thing I can think of would be a issue with the coil somehow affecting the plug

EasternArborist · Mar 8, 2023

Reach said:
That could be an ignition coil issue, but more likely that sounds to me like a clogged spark arrestor screen in the muffler. Climbing saws frequently don’t run hard enough to clear themselves out, and if you leave your saw idle a lot when you are working, it will really clog up in a hurry. I would start by disassembling the muffler and checking the screen and exhaust ports.

Roger that, Ill try this and see how she goes , will report results back, thanks again for the replies guys.

Mick Dempsey · Mar 8, 2023

Haven’t replaced the plugs in my 201 in years.

treegongfu · Mar 8, 2023

Could the spark plug wire be coming loose? Manipulate it like you were changing the plug without changing it to see of that gives you the same effect as actually changing it.

EasternArborist · Mar 8, 2023

Ill put the old plug in, clean the spark arrestor and try it out...

jmester · Mar 9, 2023

Was your plug wet with fuel when the saw would not cold start? If wet i would be looking towards your ignition module. Sounds like it maybe starting to go bad. Especially after wot load to quit and not restart. Inline spark tester would be helpful if you have one. Is the saw packed up with oily saw dust under the recoil housing. That extra trapped saw dust allows for more heat to build up.

EasternArborist · Mar 9, 2023

The plug was wet, Im going to try the simple stuff then send this off to the stihl dealer to mess with if it doesn't do it, too many things to fix and not enough time!

jmester · Mar 9, 2023

I can appreciate never enough time to get everything done. Best of luck with it

EasternArborist · Mar 10, 2023

Cleaned the saw thoroughly, pulled out the spark arrestor , reinstalled the old spark plug and she didn't go, I grabbed a fresh plug put it in and fired up on the first pull, I guess this leads to something beyond my skill set and needs to go into the shop. Dang.

islandarb · Mar 11, 2023

EasternArborist said:
Ive been going through spark plugs like crazy, when I replace them the saw works perfectly. Im replacing the plug 2 times a month, I suppose its probably ethanol in the fuel? I thought at first it was a bad batch of plugs but am on the second order. Ive never had to add anything to the mix gas since I use it up so fast but this is a pain in the ass. All the other medium/ large saws (husky) aren't having any issues, any ideas?

Sorry to hear. I have owned many. The saw usually goes to the graveyard for parts with the plug it came with. Lol. We have really good gas here though.

EasternArborist · Nov 8, 2023

Just a little update since its good news, after I cleaned the saw (last spring) thoroughly with brake clean its been running like new, haven't touched a spark plug since. Somthing was gummed up (no thanks to our pitch pine sap) but all good now, thanks again to you guys for your suggestions.