110 Johnson maintenance

kriseggy

Recruit
Joined
Jun 19, 2021
Messages
2
Hi, I'm going to attempt to get the old man's 110 Johnson running again...
I believe this Johnson is a mid 80's motor
MOD. No. CJ110TLCCA
SER. No. C8237924
It ran real good from what I can remember but, it needs a good tune up. I took the inspection cover off and noticed that most spark plug wires were detached from the boots so I wanted to replace the wires, coils and spark plugs. Would anyone here know where to start with obtaining and of these items? Any other tips & tricks would also be greatly appreciated.

thanks all!
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,878
A 1988 model.------Post the results of a compression test before you spend a single beer token.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,375
Electrical ignition parts are available at many places on the web and likely here at iBoats. Do a search and find the best deal.
 

kriseggy

Recruit
Joined
Jun 19, 2021
Messages
2
A 1988 model.------Post the results of a compression test before you spend a single beer token.
Will do!

Just one thing..., if I can't get the engine warm before my compression test, will those (cold) readings be accurate enough? I am going to replace the wires and plugs anyways, who knows.... maybe it will fire.
 
Last edited:

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,375
Compression can be measured in a cold engine. The readings need to be within 15% of each other.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,878
Well the 15 % was from long ago.---Parts are precision machined these days.-----Any difference of more than 10 PSI is a cause for concern on the crossflow motors.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,375
Racer, When cylinders go bad they have ~ 10PSI. I think a 15% variance in compression on a 35 year old motor is fine. Maybe not factory spec, but it is 35 years old.

Would you have him scrap it or rebuild it if it was more than 10% difference in compression? I would vote to run it... JMO
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,878
Yes , motors with lower compression will run.----Will not run the best.-----Looked at a 30 HP motor last year and showed owner the scored piston.----He said ----" it still runs ok " ----Called me a while ago and said no issues so far.----I think it is because folks with older / iffy motors have never hear a new or rebuilt one run !!!!
 
Top