1966 johnson 6hp only firing on one cylinder with spark from both plugs

[danielvanalphen]

I've restored a 1966 johnson 6hp (cdl- 23e)
I've replaced everything almost everything that I can, Impeller, fuel lines, rebuilt the carb, and have just replaced everything in the magneto so points, condensers, coils, ignition cable boots and spark plugs. The first time I started it after replacing the magneto it ran great and perfectly on two cylinders. However now both spark plugs are producing sparks but the boot and wire for the bottom cylinder are producing a stringer spark than the other boot. The engine only runs on one cylinder now even with spark in the other one and I've messed around with timing of the points and position of the coils and it doesnt seem to make the spark any stronger. I'm genuinely stuck and have no idea why the only one cylinder is firing.

 

[flyingscott]

Where did you het the points and condensors from? Are they cheap chinese knock offs?

 

[danielvanalphen]

Where did you het the points and condensors from? Are they cheap chinese knock offs?

No they are genuine omc points and condensers which I waited for 3 weeks to get so I'm very confused

 

[CaptnKingfisher]

I don't know much about this issue, but id start by doing a compression test on both cylinders.. I realize that you identified weak spark on one of the cylinders but that's where I'd start. You got the service manual? Resistance test on each spark plugs wire, resistance test on coil circuits, try swapping coils, see if problem follows a bad coil. You talked about replacing points and playing with timing, did you check that dwell is correct on the points? Did you put timing back to spec? What's the condition of the distributer cap?

That's all I got. Im interested to hear how this is resolved

 

[flyingscott]

What about the coils? New or original.

 

[oldboat1]

Clean and reset the points. (Some use brake cleaner to clean, some acetone.) I usually set points the old fashioned way -- rub arm at high point on the cam. Make sure the spring connectors contact the wire core.

 

[danielvanalphen]

What about the coils? New or original.

Coils I ordered new genuine omc just like points and condensers

 

[danielvanalphen]

Clean and reset the points. (Some use brake cleaner to clean, some acetone.) I usually set points the old fashioned way -- rub arm at high point on the cam. Make sure the spring connectors contact the wire core.

I took off the points yesterday and cleaned them and they looked good to me but I'll take them off again and give them a little sand and clean and see what difference it makes

 

[danielvanalphen]

I don't know much about this issue, but id start by doing a compression test on both cylinders.. I realize that you identified weak spark on one of the cylinders but that's where I'd start. You got the service manual? Resistance test on each spark plugs wire, resistance test on coil circuits, try swapping coils, see if problem follows a bad coil. You talked about replacing points and playing with timing, did you check that dwell is correct on the points? Did you put timing back to spec? What's the condition of the distributer cap?

That's all I got. Im interested to hear how this is resolved

Yeah the I never had a problem with the compression however I'm going to check both cylinders today and im going to switch the coils from the good cylinder to the bad one to see if it makes a difference. Yeah I've made sure I've set the points to 0.20 and that .022 can't pass through at the high point of the cam. Thanks for the help hopefully I can get it fixed

 

[danielvanalphen]

Ok so when running on one cylinder the motor will jump every 5 seconds as if the second one is starting but doesn't fully start. It's as if the top cylinder is only getting a small bit of fuel which is confusing as there is only one carburator. I looked at the Reed valves but didn't take off the intake manifold as there didn't look to be anything wrong. Anyone have any ideas?

 

[CaptnKingfisher]

Yeah the I never had a problem with the compression however I'm going to check both cylinders today and im going to switch the coils from the good cylinder to the bad one to see if it makes a difference. Yeah I've made sure I've set the points to 0.20 and that .022 can't pass through at the high point of the cam. Thanks for the help hopefully I can get it fixed

What about dwell? It's more important than the point gap

 

[oldboat1]

Ok so when running on one cylinder the motor will jump every 5 seconds as if the second one is starting but doesn't fully start. It's as if the top cylinder is only getting a small bit of fuel which is confusing as there is only one carburator. I looked at the Reed valves but didn't take off the intake manifold as there didn't look to be anything wrong. Anyone have any ideas?

points setting is good. (Tip -- don't remove them to clean. Run a match cover with cleaner through them.) Initial carb setting (idle air mix) is 1 1/2 open from lightly seated. Should run and warm up with that setting, then make finer adjustment. It sounds like you may be set a bit too lean (lean sneeze). Might set needle slightly richer (counter clockwise), 1/8 turn at a time to see if popping/jumping goes away.

edit. Resolve spark questions with an adjustable open air tester -- measures magneto strength. Look for about 1/4 inch strong spark.

 

[danielvanalphen]

points setting is good. (Tip -- don't remove them to clean. Run a match cover with cleaner through them.) Initial carb setting (idle air mix) is 1 1/2 open from lightly seated. Should run and warm up with that setting, then make finer adjustment. It sounds like you may be set a bit too lean (lean sneeze). Might set needle slightly richer (counter clockwise), 1/8 turn at a time to see if popping/jumping goes away.

edit. Resolve spark questions with an adjustable open air tester -- measures magneto strength. Look for about 1/4 inch strong spark.

I've always set the idle air mix at 1 and a half turns so I'll set it richer to hopefully see if that helps. Thank you very much for the help.

 

[danielvanalphen]

Ok so I've been doing research on what could possibly be going wrong and I read that on the year of the outboard I'm working on the driveshaft didnt have a dowel pin for the lower crank seal. I took off the lower unit and and where the drive shaft goes into the crank seal there are two slots at the side which I think indicates it needs a dowel pin for the lower crank seal to work properly?. Could this be the reason as to why no fuel is getting into the top cylinder as its not correctly sealed and that causes a leak?

 

[F_R]

Are you talking about 303261 roll pin? The whole seal assembly must be 100% in order to properly do it's job. Big problem is, it will run just fine with no seal at all. However that seal serves a very important function, which is to prevent water from getting into the powerhead/crankcase. It will run a long time with such water intrusion but it is slowly destroying the powerhead. Eventually, destruction will be complete. Perhaps that is where you are nearing???