Re: 74 evinrude 50hp wont go *video*
The quick and dirty way is to pull the spark plugs one at a time. Take the removed plug and touch the thrreads (ground electrode) to engine block or cylinder head. Better yet, if you take a length of mechanics wire and some around the spark plug threads and then twist/secure the other end of the wire around a stud or screw attached to the block or head. Then crank the motor (turn it over using the starter motor) while observing what is goning on between the electrodes of the plugs. You should see nice blue sparks. If you don't on one of them, that is your problem. Be careful the motor may start during the test.
Two Notes:
1. It is very difficult to see the sparks in direct sunlight. Try to do the test in a dim or shady area.
2. Be careful especially if you decide to hold the plugs against the block. The high voltage is potentially harmful - probably won't kill you, but it certainly isn't pleasant getting zapped. Most folks who mess with these motors (myself included) have been zapped mone than once, it's not fun. Just use some caution and common sense around the high voltage. If you hold the plugs try to do it with insulated pliers.
