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1986 Johnson 28hp - Need Help

D

Duckman207

New member
I am getting ignition in only the bottom cylinder. I've switched wires from the coil and power pack, but still can not get the top cylinder to fire. Not sure where to go next.
 
If you have switched wires from pack to coils and still only the bottom fires , ------you have a bad upper coil I would say.
 
No, my apologies. Here is what I have tried so far:
I have swapped spark plugs with both cylinders.
I have swapped coils and coil wires, the coils each work but will only fire the bottom cylinder
I have swapped the power pack wires, same results

I bought this motor on a boat and it had been sitting for 4 - 5 years. I do not have a compression gauge, so I can't tell if it's that. Gas is getting in to the cylinder because I can see/smell it on the plug.

I'm not sure what is going on with this one, have never seen anything like it.
 
What spark did you have before you started fixing ????----------What happens ( to spark ) when you switch the two wires from power pack to the coils ( leave coils where they are ) ????--------How are you checking for spark ????------- Exact answers are required.
 
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I think that what you are saying is that with the spark plugs removed, and cranking the engine over, you have spark from the bottom coil but not from the top coil.

Then by switching/reversing the two orange wires that lead from the powerpack to the coils, the top coil now fires but the bottom coil doesn't. This would prove the coils are okay. Now, put the wire back in their normal location.

Find the two wires that lead from the timer base under the flywheel to the powerpack and momentrily switch/reverse them. Now, if the top coil still doesn't have spark, the powerpack is faulty... BUT... if the top coil now has spark and the bottom coil does not (spark changed from one coil to the other), the problem is within the timer base under the flywheel. Remember to put the wires back where they belong.
 
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I checked for spark by looking at the plugs while ignition was on. I have one bad lead from the power pack. If I take the good powerpack lead and run it to the bottom coil, and take the sparkplug wire from the bottom coil and run it to the lower cylinder that cylinder will fire. If I run the other (bad) lead from the powerpack to that same coil, it will not fire, so I know I have a bad lead from the power pack.

If I take the good powerpack lead, and run it to the upper coil, and run that coil sparkplug wire to the bottom cylinder the bottom cylinder will fire, so both coils work off the good powerpack lead.

If I try the same combinations on the upper cylinder, it does not fire or even try to. There is spark, just not firing that cylinder.

I hope this helps explain where I am.
 
Then maybe there is not a spark problem but a reed valve / cylinder problem -------------Please note---- I looked out my front window and did not see your motor !------Do you have spark on both cylinders ( at the same time ) that will fire across a gap of 3/8" or more ???-----Exact details will help YOU in figuring this out.---------Post the results of a compression test too.
 
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I do not have spark to both cyliners at the same time because on of the leads from the powerpack is bad. I have a new powerpack on order and will get back with you after I've installed it. I'll pick up a compression gauge also. Thanks for the help, I'm new to this so I appreciate the feedback.
 
Ok I'm back. I have a new powerpack, have rebuilt the carb, am getting spark and ignition in both cylinders and it will just not stay running more that a 30 seconds to minute at most, just quits. I have 130 psi in both cylinders, and I have replaced the head gasket, both cylinders looked clean, no scarring. It will start, run ok for a few seconds and then just stop. I can restart and get the same results, the longest it has run is maybe a minute and a half. Fuel pump maybe?
 
Well , you have a manual fuel pump on the hose !!!----------What happens when you operate that while the motor is running ??
 
The timing is fixed and generally does not change and likely is spot on.-------------------Did you remove the highspeed jet ( orifice ) in the bottom of the carburetor bowl to clean it ???------------------------The thin metal arm that goes from the towershaft to the carburetor has a movable stop.-------------------Has that been tampered with ???
 
The timing is fixed and generally does not change and likely is spot on.-------------------Did you remove the highspeed jet ( orifice ) in the bottom of the carburetor bowl to clean it ???------------------------The thin metal arm that goes from the towershaft to the carburetor has a movable stop.-------------------Has that been tampered with ???
 
I was not able to remove the jet, I did clean it out and was surprised that the hole was large enough to take a carb cleaner tube. The adjustable stop has been moved, there are gradient indicator marks on the rod it is on, right now that stop is alwost all the way out toward the end of the rod that fits through the plastic sleve that holds it.
 
That stop should not be moved.----------I would suggest you take it to a shop who can correct this common mistake.------------People move that because it " appears to be wrong " when in fact it is correct.---------------How do I know this ???-------------I have over 40 years experience and have 5 ----20 / 28 / 30 HP motors to re-assemble this winter ( down to pistons and rings ) just like your motor.
 
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