1973 johnson 4 hp

[Rick.]

Re: 1973 johnson 4 hp

Before this is all finished I'd sure like you to get a different compression gauge. I just have a hard time believing the readings your getting. Anyway, it runs and your readings are even so lets just forget about the compression for now. Looks like you only have spark on the top cylinder. I would suggest you pull the flywheel so you can see your coils and points. Check the coils for cracks/burns and your points for condition and cleanliness and gap them to .020 . If you see an obvious problem that's great, if not and the coils look newer, you might switch their locations just to see if the good spark follows the one coil. If that happens you will need to buy one coil. Check the coil and points wires to make sure they haven't rubbed on something and lost their insulation. Keep us informed, or ask questions and try to get access to a different compression gauge. Rick.

 

[Rick.]

Re: 1973 johnson 4 hp

Found this this morning. Very good info. source. I just hope the link works. Rick.
http://www.shareaproject.com/pages/projectTut,p,182,00.html

 

[superd20]

Re: 1973 johnson 4 hp

just took the ignition apart. swapped coils and still the same problem on the lower cylinder. so it is not a coil. i took the points out and filed them down reinstalled at .020 gap. engine ran a little better for a minute then went back to skipping. i used a screwdriver to check for spark on the lower cylinder. it is intermittent. the spark jumps in and out. still when i take the upper cylinder wire off the engine dies and when i take the lower wire off no change.

 

[tx1961whaler]

Re: 1973 johnson 4 hp

Could be bad plugs, plug wires, coils, condensers, or points. If I don't know the history of the motor to know how old the stuff is under there, I just replace it all.
35 bucks for 2 coils, 18 bucks for points and condensers, and 10 bucks or so for plugs and wires. 65 bucks and I don't have to **** around with the thing for another 10-15 years....... some of that stuff under there could be pushing 40 years old....

 

[Rick.]

Re: 1973 johnson 4 hp

How did the coils look? Any cracks etc.? You could try running it in the dark to see if you have spark going to ground somewhere. I do agree with tx1961whaler in large measure. You would only have to do all that once. Would also suggest a new impeller if you don't know when it was last changed and a carb. kit and good cleaning. Anyway, it's up to you but let us know how your making out. Rick.

 

[nwcove]

Re: 1973 johnson 4 hp

have you tried cutting a half inch off both ends of the plug wire on the cyl thats intermittant? if you try it, they wires screw into the coils and plug boots(or the coils and boots screw onto the wires, whatever works best for you).....not push in.

 

[superd20]

Re: 1973 johnson 4 hp

i ran a completely new wire and it still did the same thing. i ordered new pionts and condensers. just waiting for them to come in so i can install them and see what happens.

 

[superd20]

Re: 1973 johnson 4 hp

I just want to say a big "THANK YOU" to everyone for your help. i installed the tune up kit and the engine runs like a champ. No skip no hesitation.