50 Johnson Not Running Right

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Posted by Ed Mc. ( on July 24, 2005 at 18:32:28:

Had to post a new reply since your subject line exceeded the character limit of the site, once the "Re:" was put in by the program.

Sounds like it might not be running on both cylinders? Put a timing lite on each spark plug wire and see if it flashes.

Then turn it off and feel the metal body of the spark plugs. Each should be quite warm to the touch if the cylinder is firing, or pulling it's own share of the load.

If you find that one spark plug is quite cool, that cylinder isn't firing or it's at least not working right.

Another 'trick' you can try is, with the airbox cover over the carbs removed, try putting a shop rag over one of the carb throats. If that cylinder is hitting, the motor will slow down. If there's a fuel problem, the motor may even speed up.

If there's no change when you block off a carb, that cylinder's not working (for whatever reason) and that's where you should direct your troubleshooting efforts.

Sure sounds like lack-of-spark symptoms so I'd check there first.

HTH and G'luck.......ed

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