Spark test on 1973 Johnson 65 hp

shawn.54

Petty Officer 2nd Class
Joined
Jun 21, 2012
Messages
104
Working with a 73 65hp Johnson it will start on muffs and run good and when you put it in the water it will start and run on high idle when you put it in gear it dies instantly and will not start and when it does has to be chocked to run when it goes into gear it dies instantly no coughing or sputtering just dies. I even checked to see if lower unit was locked but I can turn motor with prop in gear. Compression is 103-105 in all 3 cylinders did a spark test all 3 jumped 7/16 gap 2 were a little purple instead of blue/white is that right any help would be appreciated thanks shawn
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Do a drop test on every cylinder. You need to do it in the water or in a barrel as on muffs it wouldnt tell you much as there is no backpressure
 

shawn.54

Petty Officer 2nd Class
Joined
Jun 21, 2012
Messages
104
I also found it has two different spark plugs brands will pick up new champions tomorrow.
 

shawn.54

Petty Officer 2nd Class
Joined
Jun 21, 2012
Messages
104
Also noticed black peratex like material on coils around where plug wires enter wonder if this was done by past owner. I have barrel motor is on pontoon I don't want to stand on my head and play with high.voltage. Will also run until shuts off Then re spark test when it won't start.
 
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shawn.54

Petty Officer 2nd Class
Joined
Jun 21, 2012
Messages
104
We got it running dealer who cleaned and rebuilt carbs did not tighten top carb and left bolts loose inside that plug hole over low speed jet.
 
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