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This is a 4 stroke engine with overhead valves. The coil is good, per my spark tester. I shot starting fluid into the carb and got no ignition. Shot some carb cleaner directly into spark plug hole. No ignition. Pulled the flywheel and the woodruff key is intact. Checked the valves and both were within specs. Made sure the ignition timing marks line up where they are supposed to, same for valve timing marks. Still could not get the fuel to ignite. So, having eliminated fuel, spark, and timing, I suspect it is compression. Another reason I suspect poor compression is that the air filter was crumbling when I opened the plastic case and there was lots of dirt clinging to the plastic. The sparkplug hole on this machine is very small and I don’t have an adaptor small enough to use with my compression tester. So unless someone here can give me an alternate reason for the non-start condition, I’ll have to open this engine up. One more fact that might be important. There are 4 sets of tines on this tiller. Three of them had broken hubs. The hubs are solid steel with a flat side that the drive axle fits in. They must have fractured when hitting an immoveable object at speed. I would have thought that this would have caused woodruff key to shear, but it was in good condition when I inspected it. Also, oil level was very low. It holds less than 3 ounces and there was less than one ounce in it. All ideas welcome.

I have the older version FG-100, Neighbor was throwing it out, I gave it a massage & it runs like a fine watch.

I'd suggest removing spark plug, & put your finger over the spark plug hole, yank rope & if it tries to push off your finger, it has enough compression to run.


And put spark plug in the coil wire & spin engine to visually SEE the spark.. I read about your spark tester.

7394 said:

I have the older version FG-100, Neighbor was throwing it out, I gave it a massage & it runs like a fine watch.

I'd suggest removing spark plug, & put your finger over the spark plug hole, yank rope & if it tries to push off your finger, it has enough compression to run.


And put spark plug in the coil wire & spin engine to visually SEE the spark.. I read about your spark tester.

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Thanks. I did visually see the plug spark but it wasn’t easy. The sparkplug lead is so short that I couldn’t ground the tip of the plug without using a jumper wire. I did see a spark but just to make sure, I bought a new plug. Just went out to the shop and tried the finger test and only felt slight pressure, not nearly enough to push it off. So it is low compression, probably due to poor maintenance. What a pity. This is an impressively well built machine. Thanks for the lesson about testing compression with a finger! Great tip, no pun intended.

IF you are using an inline spark tester it will show a spark even if the plug is shorted. Those 10MM NGK CMR plugs are bad to go bad and whenever I have a possible ignition problem it is the first thing I change. No spark, random spark, had one that caused knocking if a failed connecting rod and even had one to a Stihl hedger to diesel.

BTW if looking up parts be aware there are four versions of this tiller.

You need around 50 psi min for the engine to fire
Have you tried some sort of starting fluid down the plug hole?
these engines have a tiny capacity and just to clean out the old fuel in a car can take better than 100 pulls.
I like to slip the carb off, turn it sideways & blow low pressure air through it to see if it is actually atomizing the fuel .
Next trick is to loosen / remove the muffler as a slight blockage in the muffler will choke the engine & prevent the new charge entering the cylinder
If the plug / ignition is bad then after 30 or so pulls the plug will be wet & smell like fuel so you know you have an ignition problem.
If it is dry then you have a fuel / valve problem

What most fail to understand with these small fixed timing engines is the spark at cranking speed is pathetically small
New fuels will happily conduct electricity at cylinder pressure and if the plug is the slightest bit damp then the tiny spark will run down the side of the electrode rather than jump the gap .
Some times heating the plug hotter than can be held in your hand will get things going as it stops the fuel condensing on the electrode .

Oddjob said:

Thanks. I did visually see the plug spark but it wasn’t easy. The sparkplug lead is so short that I couldn’t ground the tip of the plug without using a jumper wire. I did see a spark but just to make sure, I bought a new plug.

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Well ya just have to have the plug touch the engine fin for ground. I bought a new & correct plug for mine, & it ran like crap, cleaned & gapped the old plug & it just hums away.. Go figure.

I only use it twice a year at most.

bertsmobile1 said:

If the plug / ignition is bad then after 30 or so pulls the plug will be wet & smell like fuel so you know you have an ignition problem.
I it is dry then you have a fuel / valve problem

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Yep, what he said...