HS40 No Spark Kicken my butt

[Polaraco]

Hi all. I'm new to the forum.

Just a slight bit of history, I am usually the one answering these questions! I am well known in the old Mopar and diesel areas. So I have a pretty good idea what's going on. Supposed to anyway. I'm above average with mechanics, I do my own engines and transmissions, brakes, front ends, on and on.

I have a 40 year old 3KW generator which has a Tecumseh HS40 power plant. It was my Dads so it's kind of precious to me. It's serviced us well over the years, but has been replaced with larger units. I keep it around for small emergencies and want to use it on my car trailer. Several years ago it stopped running and has been dormant since. It's kicking my butt.

I have no spark. I replaced the coil and condenser, cleaned the points up real good. I will replace them when I get the new ones. Got my parts from Jacks. In the mean time I wanted to see if the spark issue was fixed. Nope! I've checked the air gap on the magnets, points are set at .020, (Several times), new plug and made sure the cam on the crank is opening and closing the points. I re-lubed the cam as well. I tested both the old and new condensers and they seem to test out fine. There are no faults in the wiring (Shorts). If I put a voltmeter on the plug wire, it will spike the meter. But still no spark. I even put an air ratchet on the flywheel and tried it. I also go brave and held the plug wire. Still nothing. There's no kill switch so that's out.

Any ideas? I'm too invested it to quit now.

Thanks in advance.
Steve

 

[jp1961]

Are the magnets in the flywheel still good? I've heard they do go bad (loose their magnetism).

Jeff

 

[reynoldston]

.020 sounds a little wide for the points. The point setting also adjust the timing. Don't know about your engine but also some engines you can put the coil in up side down and they wouldn't run. You might also isolate the engine from the chassis by disconnecting the primary wire. Also make sure your points are making good contact, because just the oil from your fingers will effect them.

 

[Rivets]

Have you checked the timing? These old tecumseh's must be set properly. Here is a manual that may help. Also check the resistance on the primary and secondary coils. Primary resistance should be between 15-20 ohms, secondary between 15000-17500 ohms. Finally, check to see if the spark plug wire is securely seated in the coil.

http://www.mymowerparts.com/pdf/Tec...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

 

[Polaraco]

.020 sounds a little wide for the points. The point setting also adjust the timing. Don't know about your engine but also some engines you can put the coil in up side down and they wouldn't run. You might also isolate the engine from the chassis by disconnecting the primary wire. Also make sure your points are making good contact, because just the oil from your fingers will effect them.

Have you checked the timing? These old tecumseh's must be set properly. Here is a manual that may help. Also check the resistance on the primary and secondary coils. Primary resistance should be between 15-20 ohms, secondary between 15000-17500 ohms. Finally, check to see if the spark plug wire is securely seated in the coil.

http://www.mymowerparts.com/pdf/Tec...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

The link takes me to a blank page

This is an internal coil. it can go on only one way. Coil wire is integrated.

Still, I should be getting something from it. This is all but dead

I'll check all this out today and click you a pic. Thanks for the comeback

 

[Polaraco]

Ahh I see what's going on with the link to the manual. Never mind. I bad

OK Timing is right on as far as I can tell, Air gap appears to be correct as best as I can measure it, and the manual calls for .020 on the points. I washed the points with some Acetone and ran a point stone through them again, chased with a dollar bill to wipe them clean. Still nothing

Even with the timing off, I should at least get some spark.

And yes, magnets are good. I've checked and rechecked so many things I forgot what I did.

Maybe it's too simple. I'm missing something. LOL

I can make you a whole wiring harness, but I can't get this old dinosaur running. :laughing:

 

[Rivets]

Don't know why the link does not open, works fine on my end. I know the type of magneto system you have and it must be timed. If you can't open the link, do a google search for Tecumseh L-head engine manual. You should find open online as they are out there. Try this site.

http://www.barrettsmallengine.com/manual/tecumsehlheadmanual.pdf

 

[Polaraco]

Don't know why the link does not open, works fine on my end. I know the type of magneto system you have and it must be timed. If you can't open the link, do a google search for Tecumseh L-head engine manual. You should find open online as they are out there. Try this site.

http://www.barrettsmallengine.com/manual/tecumsehlheadmanual.pdf

Yeah I acknowledged the link problem in my last post. I was being stupid. LOL

Take a look at my last post. I'm baffled now

 

[reynoldston]

Very simple system. Coil with three wires. primary, secondary, and ground. Primary has no grounds to it? Secondary wire to the spark plug which is in good shape, ground wire to the ground. Coil in good shape and not grounded out to the coil legs, Points and condenser good to go. The only thing that sets the timing is point gap and coil air gap. Magnet are good. Just try to set the points a little closer and make sure you have good continuity through the points. It a new one on me seeing I never ran across that problem and I have worked on that system many time but also had to recheck my work to get spark some times.

 

[Polaraco]

Very simple system. Coil with three wires. primary, secondary, and ground. Primary has no grounds to it? Secondary wire to the spark plug which is in good shape, ground wire to the ground. Coil in good shape and not grounded out to the coil legs, Points and condenser good to go. The only thing that sets the timing is point gap and coil air gap. Magnet are good. Just try to set the points a little closer and make sure you have good continuity through the points. It a new one on me seeing I never ran across that problem and I have worked on that system many time but also had to recheck my work to get spark some times.

Yup Yup and Yup again.

I checked the timing today, Had to wing the TDC. Turns out the adjustment is all the way over. There is no more. But it looked to be with in spec. I tested the coil condenser both old and new. All are still good. The lack of spark was what started this nightmare.

Here's a killer. After reviewing my work, 10 times, I turned out the lights in the shop and spun the flywheel. I got one healthy snap and nothing after that. I took the flywheel off and cleaned the points one more time with a dollar bill. (An old mechanics trick) There was a little dirt on them, and frankly I am very surprised there was anything on them at all. My bad again.

In the process, I lost the crank key. Ugh. I hate it when that happens. I stuffed an allen wrench in there and locked it in and still nothing.

There has to be something going on in those points, It's all that left!

Off to the parts store now (Jacks). . . . I'll be back (Arnold :laughing

Merry Xmas