replacing plug wire

[jonmac]

I have a mid 70's Johnson 20 hp. and it hasn't been running right. Found today that the lower spark plug wire is burnt and shorting against the hood latch.

How hard is it to change that myself, it looks like I will need to pull the flywheel in order to do this, is this correct? and also where do I find the plug wire to buy from?

Also there is a vacuum line fitting on the right hand side (standing behind the boat and looking at the motor) that is very small and the only place that I can see it goes to is another hookup under the carb. but it is twice the size so the vacuum line would have to have 2 different size ends to work. What am I missing looking at this?
Right now I have them both blocked off with screws but really want it right.

Thanks in advance.

 

[stevesecotec02]

Boatparts.net will have the parts u need and also shows parts diagram. Wish I could help you more but I don't know much about the older motors ignition systems that don't use magnetos.

 

[dkonrai]

iboats or marineengine, vintage outboard many sites that have the wire and boot. even ebay. depending on the year, the spark plug wires are either under the flywheel or (im guessing you cant see the coils?).

pull the flywheel. if the coils are cracked you must change them. if they are black in color and not cracked, then you lucked out. replace the points, and condensers too. when you replace the wires, its best to remove the coils and twist in the new wire then reinstall the coil. points should be set at .020. put in some new plugs and give her a try. these are great motors and will start really easy when tuned correctly. i have had a few 18/20/25 hp motors, and they run really well. best power to weight ratio.

good luck. if you get into a bind, check leeroysramblings. good stuff there, and iboats forum for some info if you get stuck.

dino

 

[jonmac]

How hard is it to pull the Flywheel?

What tools would I need to do this?

Is it backyard mechanic do able or should I breakdown and take it to a shop?

I have never worked on a boat engine but have worked on vehicles alot.

 

[dkonrai]

rent or buy a steering wheel puller.
buy (3) 1/4 x 3 grade 8 bolts, (6) washers.
place the puller on the fw, thread about 3/4" or so of the bolts into the puller.
use the tool to pull the fw, sometimes a little rap on the top of the puller nut will help pull the fw.
easy job, check leeroysramblings. it will spell out the job pretty much step by step.
i use a little soap to help pull the wires through the boot. (start at the boot first).
dino