# Stihl MS 290 No Spark



## etbrown4 (Dec 11, 2011)

I see no spark on the plug when I ground it against the carb, and pull the rope.

I've tried 2 plugs.

I have the choke in the 'full choke' position.

I have the chain brake 'on' or thrown forward.

Shouldn't you be able to see a spark when pulling the rope?

What is the next step?

Any tips are appreciated.


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## etbrown4 (Dec 11, 2011)

Some say that you can't ground a plug against the carb on this model Stihl.

If so, how to you test the plug while watching for a spark?


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## etbrown4 (Dec 11, 2011)

I have found that sure enough, I do have spark. 

To see it, I have to take a piece of copper wire, wrap it around the base of the plug and let the other end contact the head. Bingo, plenty of spark, though it's yellow.:smile2:

Now, the plot thickens. With 'ether' shot into the cylinder or through the carb, I am getting zero firing in the cylinder.

I've worked on lots of different motors including thousands of hours flying and working on 2 cycle ultralight airplane motors.

For now, I'm stumped. How can you have fuel and spark and no fire?:frown:

Is this unique to a Stihl, because I can't recall seeing this before and that covers 50 years of twisting wrenches!


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## Ironmower (Sep 19, 2010)

Next step would be to check compression.. For it to even attempt to start it needs to be above 100 psi ( all thou Iv'e seen 1 run half-azzed at 90) This saw should be in the 150 psi neighborhood..


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## brucew44guns (Jan 8, 2012)

Is it getting fuel into the carb? Did you try a "new" plug and gap it right? Next step, I'd take it to a shop that works on Stihls, tell them not to overhaul the whole saw, but find ouit why it won't run and start. I've found a couple Stihl dealers here that treat me somewhat fair.


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## Knucklebuster (Jan 14, 2012)

etbrown4 said:


> I have found that sure enough, I do have spark.
> 
> To see it, I have to take a piece of copper wire, wrap it around the base of the plug and let the other end contact the head. Bingo, plenty of spark, though it's yellow.:smile2:
> 
> ...


I wouldn't be spraying starting fluid into a saw. You'll score your cylinder and then have a whole lotta trouble on your hands. Get yourself a little spray bottle and put some pre-mix in it; use that instead. 
I made myself a little spark tester just as you put together by using an old but good plug, wrapped with copper wire that I wrap around the top of the existing plug. You'll want to cut the electrode off to the elbow though. That way you'll be able to see the spark better and you'll know you have "Good" spark if it can jump that gap.


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