79 100 hp johnson itermittent cylinder loss

[JFe915]

1979 100 horse power johnson sea horse.am experiencing itermittent cylinder
loss of 1 or more. motor starts up while idling or at high rpms cylinder cuts in and out intermittentedly. sounds almost like a compresion release of some sort. checked the coils and power packs according to the manual they came up fine unless theirs some kind of leak from a coil i cant pickup. compresion is
105,120,120,120. i recently replaced the timer base and stator also. could the timing be out? Thanks

 

[JFe915]

Re: 79 100 hp johnson itermittent cylinder loss

bump

 

[JFe915]

Re: 79 100 hp johnson itermittent cylinder loss

bump

 

[boobie]

Re: 79 100 hp johnson itermittent cylinder loss

How did you check the coils and power packs and what manual are you using ?? With an open air gap spark tester what size gap is it jumping ??

 

[emdsapmgr]

Re: 79 100 hp johnson itermittent cylinder loss

Weak ignition components tend to fail when the engine heats up to normal operating temps. You can check the spark on each coil wire with an inductive timing light. The flashes in the light will show misfires, weak firing and non firing. Best to check the ignition when the engine is under load, like idling in gear at the dock. Your ignition system has two parts, one power pack drives the spark for each head. These packs can be swapped for testing the ignition system.