Stihl MM55C Cultivator *Mantis Like"

gilephor said:

Well, i do not have a tester but there is spark to the boot as confirmed by a shock to the finger When putting my finger on the bottom of the boot and having my son pull the cord it shocked me

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OK...if you can "feel" the spark, the next thing to look for is the "timing" of that spark. There is a flywheel "key", a small half moon shaped "washer" locks the flywheel into position on the crankshaft. These sometimes sheer, and the flywheel rotates away from the proper timing of the spark. If you remove the nut holding the flywheel to the crankshaft, you should see a "slot" on the flywheel and a matching slot on the crankshaft. If these do Not line up, your spark will not be occurring at TDC of the piston.
Also, did you pull the plug after several cranks to see if it is "wet"...indicating that fuel IS getting to the piston??

Dump out the gas again, and pull the plug again, and totally dry it all out again.

Then when you are sure it is all dried out internally, still put no fuel in the tank. Put the plug back in and attach the wire. But with the air filter off, pour a dribble of clean fuel into the carb again, and pull/try to start as you would normally.
See if after some pulling, you get the engine to fire up and run until it burns off the dribble of fuel.

Try this test before you start tearing the trimmer into pieces.

Let us know what you find.

Ok so I bought an in-line tester hooked the long end into the boot, the other end to the spark plug seated in the cultivator. I could not see any light or anything from the tester. So does this mean I need something like this? When I did pull the plug it was wet and smelled of gas.

http://www.boxstoreparts.com/Stihl-Ignition-Module-Coil-4140-400-1308-4140-400-1308.htm

Correction: it is getting spsrk so i will try other suggestions.

gilephor said:

Ok so I bought an in-line tester hooked the long end into the boot, the other end to the spark plug seated in the cultivator. I could not see any light or anything from the tester. So does this mean I need something like this? When I did pull the plug it was wet and smelled of gas. http://www.boxstoreparts.com/Stihl-Ignition-Module-Coil-4140-400-1308-4140-400-1308.htm

Click to expand...

The "Wet" plug should indicate that you Are getting fuel to the piston, so Ignition is the most likely culprit. The picture you posted is the coil, and at a reasonable price. Since you say you felt a "jolt" when you held the plug wire, you might try the tester you bought on another motor...lawnmower, etc., to make sure you didn't buy a defective tester. If the tester checks out ok, and you still get no light, then the coil is a good bet. However, I would still check the position of the flywheel on the crankshaft...those flywheel keys do break....and while you are there hold a metal feeler gauge or small screwdriver near the flywheel magnet to see that it still has good "magnetism", and attracts metal strongly. If the flywheel checks out ok, then the coil is your best bet. Oh, and one more thing....you could have a bad "Start/Stop switch, which is shorted such that you are on "stop" all the time. There is a wire on the side of the coil which comes from the switch, and you can remove that wire to see if the switch is shorting out the coil, and keeping you in Stop mode.

Another tip on small Stihl engines....they do tend to "flood" quickly. I have the MM55, two Stihl trimmers, and two Stihl chainsaws, and they All flood easily. After sitting for some time, I have found that I can only pull the rope once or twice at full choke, then release the choke to get the engine to start with one or two more pulls. If I leave the choke on for more than two pulls, I usually wind up flooding the engine, then I have to pull the plug and let the engine "air out" before trying again.

That's about all I can think of...If none of this helps, you may have to take this rascal to a shop, and let someone who does this for a living, take a look at it.

Dry it all out totally as I suggested,
And you can know with a bit of certainty if your problem is fuel or igntion related.

And dry the plug properly
Modern "fuel" which is nothing like petrol leave an oily deposit on the centre insulator on the spark plug.
This deposit is not conductive in air so you get a spark at the electrodes when you ground the plug to the side of the engine.
However when you put it in the engine, the spark runs down the side of the insulator in place of jumping the gap