Stihl MS 290

[harryevan]

Okay, one more time today:

I bought a Stihl MS 290 a few years ago for firewood - I used to be a climber but I fell out and now I'm a database manager, go figure - anyway, it cut like the hot knife going through butter for a while and 3 chains saw me through a day's cutting, no problem. I'm still on my first pack of Stihl 2-cycle oil, so it's not like I'm cutting cords every weekend, just a couple times a year.

One day, last year, I couldn't get it started. Took it to the dealer who said the fuel line was cracked (too much alcohol in the gas these days?), so he changed that and rebuilt the carb. "Don't keep fuel in the tank if you're not using it." Okay, sounds good. I do that.

About six months later, it stopped after the first tank. Refueled, more oil, checked the chain - couldn't start it again, so I bagged it for the day and dumped the fuel out. After a few friends tried starting it, I took it back and the guy changed the plug and said it started for them. I got it home and dumped it out as I wasn't using it for a while.

Today, it won't start. New gas mix, nice day. Go through the manual's steps, but it won't even give me a tease. Flooded? I pulled the plug, pulled it through and blew it out like the guy did at the shop, plenty of fuel in the cylinder. Filter's fine. The one in the tank appears new, nice an white, nothing clogging it. Checked the plug for spark - that's fine. Still won't start. Just on intuition, I check the switch leads with a meter. They show continuity in all positions (I thought it would just be in OFF.) I pull the green/yellow wire and I just get continuity in OFF.

I pull the starter cover and pull the black wire lead on the coil. I get continuity between that connector to the coil and the green/yellow wires bolted to the frame of the coil. I pull the coil out (so it's not grounded) and I get continuity between the black wire's coil connector and the frame running through the coil that gets bolted down with the green/yellow leads.

Am I looking at a new coil, or just in need of something else (quart of Jameson's?)

harryevan

 

[galde]

If you have adequate compression (120 psi or better), strong spark (test with tester or old plug with increased gap), and fuel (to ensure no flooding, you can close off the high and low needle valves and prime with a teaspoon or less of fresh fuel into the carb) and it won't fire, the problem could be in timing.

 

[harryevan]

So it's normal that the coil is shorted like this? I would have thought that the "kill wire" needed to short out the circuit to stop the engine. Doesn't really explain the spark I'm getting.

So, how much more should I open the gap (it's at .020 now).

And what's the magneto gap? Like the dumbass I am sometimes, I forgot to check it before I pulled the coil. Then there's timing...

Thanks

 

[cop0110]

Sell it brother and get a 361..... Man I love mine.......................:chainsawguy:

 

[Bowtie]

So it's normal that the coil is shorted like this? I would have thought that the "kill wire" needed to short out the circuit to stop the engine. Doesn't really explain the spark I'm getting.

So, how much more should I open the gap (it's at .020 now).

And what's the magneto gap? Like the dumbass I am sometimes, I forgot to check it before I pulled the coil. Then there's timing...

Thanks

Loosely bolt the coil on, then use a business card to set gap by rotating the magnetized flat part of the flywheel in line with the coil. Tighten the coil bolts down. Remove the card. Gap is close enough to perfect to work every time.

 

[harryevan]

Ain't an option. I'm happy to have a Stihl, as it did work great for a while. Beats the Homelites I used to use, in a different life - back in Akron...

But thanks.

 

[cop0110]

I understand that, its a stihl.. And will serve you well... Bowtie has good advise let us know.....:chainsawguy: :chainsawguy:

 

[Octane]

This is just a shot in the dark here, but when you dumped the gas out of the saw did you then run it so that you got all the gas out of the carb?
If you didnt, its possible than that carb is all gummed up from the varnish that the fuel left when it evaporated and thats why it wont start.
If you did run it out of gas, Id be leaning towards the coil gap not being right or the timing being off.

 

[J_Ashley]

Sounds like it could be a coil problem. Do you still get spark when pulling in the "run" position?

I have a MS 290 right now that seems possessed. It will start and run briefly when it's cold, however it won't idle, or rev properly. I also notice it wants to die when I point the bar down toward the ground. This goes on for a minute and then it refuses to run...

Sucking air maybe? Or perhaps the carb's "L" jet? I've tried, but can't adjust this problem out. The spark-plug was caked with light-tan colored depostits, and I assume that means it's running lean? I pulled and cleaned the carb, checked the fuel line for cracks, and tried again, but no luck. Perhaps a crank-vent hose, not pumping fuel maybe?

I thought about replacing the fuel line and crank-vent hose and going to a weighted fuel-filter in case it's sucking air somewhere... Is this the right direction? I imagine that a carbuerator is in the 70-100 dollar range, and there's still no gurantee it'll work. I'm trying to exhaust all possibilities before shelling out 600+ for a new 361... Any ideas fella's?

 

[harryevan]

I hadn't had reason to run it since I got it back from the shop the second time. Should have started it, just to be sure, but I didn't. Carb looks extremely clean, though. It would never really rap up all the way, which I thought might be the altitude, but I don't want to mess with the carb at this point.

I'm just thinking that the coil wouldn't normally be shorted like that, and that there should be at least some resistance in the circuit in the RUN and START/CHOKE positions, as the contact on the switch is only making contact in the OFF position. And, yes, I did get some spark in the run position. I don't know if it was enough, but I could see it, with the plug wrench making contact between the plug well's threads and the plug's threads.

I don't have the $600 for a new saw either, especially when this one isn't really old yet - it was hard enough convincing the wife that $325 wasn't too much for a Stihl.

I'll check in town to see what a new coil will set me back and ask about the continuity check, probably take the meter with me to explain the question.

I'll let you know what happens, in any event.

Is that Mr. Blue Bowtie from the auto forums? Good stuff, there.

 

[Bowtie]

I hadn't had reason to run it since I got it back from the shop the second time. Should have started it, just to be sure, but I didn't. Carb looks extremely clean, though. It would never really rap up all the way, which I thought might be the altitude, but I don't want to mess with the carb at this point.

I'm just thinking that the coil wouldn't normally be shorted like that, and that there should be at least some resistance in the circuit in the RUN and START/CHOKE positions, as the contact on the switch is only making contact in the OFF position. And, yes, I did get some spark in the run position. I don't know if it was enough, but I could see it, with the plug wrench making contact between the plug well's threads and the plug's threads.

I don't have the $600 for a new saw either, especially when this one isn't really old yet - it was hard enough convincing the wife that $325 wasn't too much for a Stihl.

I'll check in town to see what a new coil will set me back and ask about the continuity check, probably take the meter with me to explain the question.

I'll let you know what happens, in any event.

Is that Mr. Blue Bowtie from the auto forums? Good stuff, there.

If you bought the saw new, the coil should be under lifetime warranty.

 

[harryevan]

Success!

Hey Mr. Bowtie. Thanks! The card trick worked fine!

I was just about to give up, put it all back together and take it in to a different dealer in town. I had broken it down quite a ways chasing this problem, so the chain brake reassembly gave me a problem until I realized I could pull the band itself out and re-install it after I got the linkages and springs back in.

So I got it reassembled, using the card trick on the magneto gap, put the switch in cold start and pulled the cord to be sure everything was moving correctly and it started on what fuel was left in the line, carb and cylinder - actually had to shut it off.

Today, the district Stihl guy said the gap is .008. The best way to "unflood" a Stihl is to pull the plug and invert the saw, and that it's best to have a spare plug as they don't always dry out fast enough. Just thought I'd pass that along.

So, I'll fuel it up and give it a try when I get home.

Thanks again.

 

[kevin callahan]

if you are getting fire and gas it should run but maybe not enough gas. These stihl carbs are very sensitive, a very small splinter or dirt of some kind will disrupt proper fuel flow through carb, try taking carb back off and simply clean it out good with carb cleaner. This will probably solve your problem. If you do need parts for this saw i have a 290 parts saw.

 

[Fish]

If you do need parts for this saw i have a 290 parts saw.

MMMMNNN.
Where in Ky. are you?

 

[harryevan]

Thanks for the help, Kevin. I looked at it pretty closely while I had the carb out, looks real good. I ran a tank through it cutting firewood last night and, outside of setting the carb back to the recommended start point and adjusting the idle, it ran GREAT.

Like I said, better than the Homelite's I used to deal with.

 

[J_Ashley]

MMMMNNN.
Where in Ky. are you?

Fairdale's on the out-skirts of Louisville in Jefferson County... Around, a little west maybe of I-65.