1956 johnson 7.5 no spark on bottom cylinder

[RDP56]

I have a 1956 7.5 johnson I think model# AD-10 serial#1362075 it runs on the top cylinder and no spark on the bottom cylinder. I switched the spark plugs and it still runs on the top cylinder with no spark on the bottom. where do I need to start to find the problem? I would really appreciate any help.

 

[ddwilson]

Re: 1956 johnson 7.5 no spark on bottom cylinder

I would check the points and condenser first and take a look at the coil while you are in there and if it is cracked
replace it.

 

[RDP56]

Re: 1956 johnson 7.5 no spark on bottom cylinder

thank you ddwilson that sounds like the place to start

 

[HighTrim]

Re: 1956 johnson 7.5 no spark on bottom cylinder

If the coils are original they are no good. Replace them. They will be badly cracked if original.

If the points are badly pitted, just replace them. Tune up kits are cheap.

If just dirty, dress them by running 600 grit folded in half through them, then set to 020. Dip card stock or clean paper in acetone or laquer thinner and run it through to clean. Also ensure you are getting good continuity through plug wire from secondary. Ground lead to plug boot should get 3000 to 8000 ohms resistance.

 

[RDP56]

Re: 1956 johnson 7.5 no spark on bottom cylinder

thanks HighTrim that is some good information I need all the help I can get

 

[kfa4303]

Re: 1956 johnson 7.5 no spark on bottom cylinder

Hi RD. Here's a great link that can walk you through an entire ignition rebuild. It's for a slightly different model, but all of the steps are the same. You can get a tune up kit and coils right here at iboats for about $20 each.

3 HP Evinrude Lightwin Ignition System Tune-Up 1952-1967

 

[RDP56]

Re: 1956 johnson 7.5 no spark on bottom cylinder

thank you kfa4303 those step by step instructions with pictures are exactly what I needed. I am more confident that I can do this repair on my motor now. I have found the tune up kit and coils on iboats just as you said. Thanks again.

 

[kfa4303]

Re: 1956 johnson 7.5 no spark on bottom cylinder

No problemo. Good luck. Holler if you get stuck.