Tecumseh HH60-105096F weak spark

[lgw7]

I am trying to help a friend get an old Troy-Bilt rototiller going. It runs, but erratically. It sounds like it is getting spark only intermittently. I pulled the spark plug and hooked the wire to a KD standard spark tester. There was no observable spark when I pulled the starter rope to crank the engine. I tried again with the spark plug resting on the shroud, and I saw the spark. That seemed to indicate to me that the spark was weak. This engine has points, condenser and coil under the flywheel. At this point I have installed a Stens solid state module (which bypasses the points and condenser) and a new coil and spark plug wire. After I put the solid state module on, but before installing the new coil, I was able to see a spark across the spark plug, but not across the spark tester. After also installing the new coil, there is no spark either across the spark tester or the spark plug. I then disconnected the solid state module and connected the new coil to the old points and condenser. At that point I again had spark across the spark plug, but not across the spark tester. The steel flywheel key is OK.

I tried the spark tester on another Tecumseh engine that I had on a DR Trimmer, and saw spark across the tester, indicating that the tester is working OK.

So, should I not be seeing spark across the tester when hooked up to the HH60 engine if the ignition system is functioning normally? And if the spark is only visible across the spark plug and not across the tester, does that not indicate a weak spark? What else could cause a weak spark but the coil, spark plug wire, and the solid state module? The flywheel magnets test OK with the "attract a screwdriver" test.

[smitty6398]

Put in a set of points and condensor and recheck the spark. A good coil will usually jump 1/4" or more.

[XLerate]

Rust, corrosion or paint on the flywheel or armature can cause a weak spark, as can incorect air gap between these two parts. Also a faulty wire or poor connection or bad connector can do it. As you know, it's a system, so all parts have to be playing nice together.

[Arkie]

Put in a set of points and condenser and recheck the spark. A good coil will usually jump 1/4" or more.

I agree with smitty as a first try!
Put in a set of NEW points at the correct gap of .020, NEW condenser, and make sure the NEW spark plug gap, (usually .030,) is correct! (install these with the new coil)

After installing the NEW points, rotate the crankshaft to open the points then insert a $1 to $100 bill and drag it through the NEW points about twice to remove and light oil residue! (Use a $100 bill and you won't forget to remove it from the flywheel area before installing the flywheel!


If you are fooling around with new coil (Inside the flywheel) you will have to reset the BTDC timing to correct specs! (see a service manual for such) their are links for a FREE download manual for this model, I think) (if the BTDC is not correct you may see good spark, but the engine may now act like a bad carb!

[lgw7]

Thanks for the help guys. I applied the first suggestion and put in new points and condenser. I set the point gap with a feeler gauge and dragged the clean paper through the points to remove any oil. I set the timing when the head was off with a dial indicator. When everything was back together, the normal spark was restored across the spark tester. Since that was so, I am guessing that the solid state module was or became defective as I worked through the process since it did not work with the new coil in either polarity setup.