This has me stumped.

[john hall]

Go back to post #5. Everyone here helped chase that guys problem and he found out it was faulty ignition part that, I think, was new. Research his thread, it was very educational and certainly worth filing away. If they sent you one bad coil, seems to me the next one could be bad as well if they were from the same lot. Not saying that is the problem, but all things are worth considering.

[DieselDoctor]

Yes, mine was a bad "new" coil. There glue holding the wires into the coil became an insulator then it had a weak enough spark causing a skip.

[J-Mech]

Originally Posted by flatpickerray

Why are you sitting this one out? I was hoping you would have the answer to the original question. "How does cutting off the air affect the spark?" Just cranking the engine there is little to no spark, when I block all air going into engine I get normal spark, using a spark tester.

Lol. It was too entertaining to not sit back and watch a while.

George nailed it in post #9. To fix this, it would probably be easier with the engine out. He's right on about what plugging off incoming air is doing, and why it seems to help. Sounds to me like you have a bad magneto.

[flatpickerray]

Originally Posted by Oak

I'm with George, less compression. What kind of spark do you get if you pull the plugs? I'm thinking the new ignition module is the issue.

With both plugs out and grounded, I get a weak but consistent spark on both.

The general consensus seems to be a bad coil so I'm going with that. I'm going to order an OEM this time instead of aftermarket.

I'll report back when I get it installed. Thanks for all the input everybody.

[darkminion_17]

Originally Posted by J-Mech

Maybe I'll just sit this thread out......

I tought it was a puddy cat, I thought that was quite imaginative with the wood thing.

[Jeff in Pa]

Originally Posted by jbrewer

If you miss and hold a leaky plug wire, that's not ALL you'll be saying !

I figured out quite quickly why spark plug wires have thick insulation on them when video taping this buzz box for my hit and miss engine.

https://www.youtube.com/watch?v=dGVoOPqjBOI

https://www.youtube.com/watch?v=4cWu8K5hm-M

Let's just say it got my full attention quickly.

[DieselDoctor]

When you get your new OEM coil, make sure to set the air gap between the legs of the coil and the magnets in the flywheel. As others have mentioned above, this can make the difference between a hot spark and a weak one.
When installing a coil, I loosen the mountings screws and slide the coil as far away from the flywheel as possible, then lightly snug the screws to hold the coil there. Now after rotating the flywheel until the magnet is directly under the coil, I place a standard thickness paper business card between the legs of the coil and the flywheel. Now loosen the screws and the magnets will pull the coil into place. Tighten the screws securely, and rotate the flywheel to remove the business card. Your air gap should be right around the .008" spec. The paper of a business card is right around .008 - .010" thick and is the perfect tool to quickly get the coil installed evenly and at the correct distance from the flywheel.

[J-Mech]

Question is, who's business card do you use?

Maybe I can get some with a picture of Hillary on them....

[DieselDoctor]

Actually Jon it's a business card from one of our sponsors at the top of the page. It was included in a shipment of parts a few years back, and I threw it in the top drawer of the tool box "just in case". Been using it as a gap tool ever since!

[Alvy]

Originally Posted by DieselDoctor

Actually Jon it's a business card from one of our sponsors at the top of the page. It was included in a shipment of parts a few years back, and I threw it in the top drawer of the tool box "just in case". Been using it as a gap tool ever since!

Sounds like it replaced your “out of spec” matchbook