Not firing on 1 cylinder on a V4

[Mdraper530]

I have a 1964 Johnson 75 hp outboard. I have ran this motor numerous times and seems to be okay no major problems. Other than I think it might be idling a little to high for my liking. But when I checked the spark plugs 1,2,3 had black on them like they have been firing. and then checked #4 and it was just wet. I had just recently changed the spark plug wires so it could be just that plug I dont know. I dont know how this motor ran before the wire change. I have not checked compression yet. Every time I tried it didnt work but it does run. What do you guys think?

 

[ONERCBOATER]

Re: Not firing on 1 cylinder on a V4

i think you should be looking for spark....1st on number 1
try removing plug....and just resting plug on block to see if there is anything there....if so next would be spark tester and a 1/4-3/8" jump of a healthy blue spark. if no spark found...1st cheang wire...and plug for known good one...then swap coil. As a 1964... gussing you have points... worth checking them and the condensors out at the same time if you have to go under the flywheel to check coils (not sure on this motor). at least that is the path I would take, unfortunately i am not real familiar with that model as you can likely tell. If someone else chimes in take their suggestions over mine.

 

[Chris1956]

Re: Not firing on 1 cylinder on a V4

That motor should have two sets of points, a single condenser and a single coil. They will normally have no spark, spark to 2 cylinders or spark to 4 cylinders. I would think you have spark to the #4 cylinder, but is likely running rich, as the bottom cylinders will do, especially if the carb is out of adjustment and flooding.

I would verify that you have spark on all 4, and then start by checking the carb float and inlet needle. Does that motor have the adjustable high speed jets? If so, you might lean out the high speed needle opposite where the fouled plug is. I think they cross the carb intakes in the intake manifold, but do not accurately remember.

 

[Mdraper530]

Re: Not firing on 1 cylinder on a V4

Yeah just changed the spark plug cables, spark plugs, condenser, and points. The carb is probably out of adjustment. Just right there would cause this cylinder to not fire?

 

[Chris1956]

Re: Not firing on 1 cylinder on a V4

Sure, the plug will be fouled with oil an gasoline. Also watch for water, as that can "put the fire out"