79 Johnson O/B needs major help!

pguest44

Cadet
Joined
Jan 22, 2007
Messages
10
79 Johnson 100 O/B- Model-100TLR79S op. range 4500-5500

Okay here's the run down...I haven't run the boat in 2 years due to no time (lame excuse I know), but the other reason is I have had some problems with the engine and wiring. I kept blowing the fuse on the port side of the engine off of the solenoid after running the boat for a few minutes in drive, but idling no blow. I could run the boat all day with the blown fuse as long as I didn't shut it off. Had to replace it to get it started (makes sense though). I think I found the problem, burnt wires...but if that doesn't fix it could it be a bad solenoid? (and I just cleaned ALL of the terminal connections on everything today and replaced a few of them that were over corroded)
Next, the bilge pump wasn't working until today, but the problem is it isn't sucking any water in to the pump.
Okay, and now the wiring...
When I first got the boat around 2003 I replaced the wood panels on the inside on the of the boat, port and starboard side. The starboard side holds the instrument cluster, and when I replaced the panel on that side I had to disconnect some of the wires. I think some where along the way some of the wires were placed in the wrong positions. I have a fuel gauge, on the panel, bilge switch (auto and manual), lights and horn button. They all worked at one time but not anymore.
Oh and the tilt trim isn't working but the motor is running. I think I have a fix for it though from reading on the forum.
Now all the problems are out there, my main questions are: Does anyone have a wiring diagram for solenoid (just to check my work) and a wire diagram for the instrument cluster for the harness to the cluster?
Thanks guys I love this site and love to read all the posts!
 

JWH0420

Seaman Apprentice
Joined
Jun 6, 2011
Messages
49
Re: 79 Johnson O/B needs major help!

most of ur issues will be tough to fix being no boat i know of (boat itself not motor) has any form of a normal electrical system and usualy resembles a rats nest of wires with a severe lack of fuses which i find rather odd concitering coast guard regulations about fire safety but the fuse on your motor sounds like main power fuse and the fact that it pops when u run higher rpms makes me think u have a charging problem over voltage more than likely bad rectifier
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 79 Johnson O/B needs major help!

There is a wiring diagram in the back of the factory service manual. You can get an original manual from Outboardbooks.com. You have two fuses on that enigne. One is in the main wiring harness on the port side of the engine. The second is in the power trim box. You need to have two good fuses to run both the engine and the trim. You can run the engine with the control box unplugged at the engine. Would be interesting to know if the engine harness inline fuse will blow if the control box is unplugged/disconnected. If it does not, you can look for a short in the control box wiring or key switch. Keep in mind that in order to shut the engine off, you must have the control box connected-to short out the power pack.
 
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