Engine electrical issues driving me nuts

First let me say all of my boats electrical and electronics are in great shape. I have had no problems at all this year with any of the pumps, lights, radios or electronics. The engine electrical is driving me mad tho. Back in May when I rebuilt my powerhead I cleaned up or replaced every electrical connection on the boat and the outboard they still look good but something is happening. Here is the low down.

The first problem has been corrected and I believe it is unrelated to the other problems but I thought I would mention it just in case. A month or so my engine tach quit working, the problem turned out to be a burned out rectifier it has been replaced and hasn't given me any problems since.

Then a few weeks back my engine became very hard to start cold. At the time I didn't realize the problem was the primer was not working. Two weekends ago my tilt/trim went on the blink. I switched around relays and it acted just like one of the relays was bad so I replaced the bad one and the tilt and trim started working again. Last Saturday I went out to start the motor and the tilt/trim was on the blink again. Once again switching wires and relays led me to believe the new relay was no good so I purchased another new one and the tilt/trim was back working fine. I started the engine and ran it a while but when I turned the key off it kept running. I pulled the fuel line and let it idle out of fuel then went to work on the problem.

While working on the key switch I got a wild idea thinking that the cold starting problem I had been experiencing might be due to the primer. I hit the primer button and heard no click...Ah Ha. By this time I was getting frustrated so I decided to take a break. Before breaking I hit the tilt/trim and guess what? It was on the blink again.

After a short break I went out and started going through the engine electrical thoroughly and all looked good until I pulled the 25 amp ignition fuse. The fuse was badly corroded. I cleaned up the holder the best I could and put in a new fuse. To my suprise everything but the primer started working.

Yesterday after work I went out to investigate the primer problem. I pulled out the key switch and took lose the purple/white primer wire. I touched a hot wire to it and the primer clicked. I plugged it back into the key switch and hit the button and magicaly the primer is working now. I went to start the motor and the key switch was dead. I went back and pulled the ignition fuse and inspected the fuse and holder then plugged the fuse back in. I tried the key and it started. I turned the key off and the engine kept running. I got out of the boat to look at the outboard and the engine quit, it didn't sputter and quit it just quit as if you switched the key off.

It is really strange all these problems off and on but I'm thinking I need to cut that fuse holder out and replace it. What do you think?

Re: Engine electrical issues driving me nuts

Fuse holders can cause problems, replace it and you have eliminated one problem.

Re: Engine electrical issues driving me nuts

2nd vote- replace it

Re: Engine electrical issues driving me nuts

Well after a full day of trouble shooting I found my problem. I was about to throw my multi meter in the trash and give up because everytime I would check continuity on a wire I would get a different reading. I was checking the wires from the keyswitch to the various ignition system components and my meter would read one thing and the next time I checked that wire it would read something totally different. The wire that grounds out the powerpack to kill the engine showed continuity but way more resistance than a single wire should read. Finally I hooked a wire directly to the off terminal of the key switch to the power pack and all my troubles went away.

I started tracing that black and yellow wire to see if it was cut somewhere and found it was burned into right where the boat harness enters the bilge. It was held together by just a little bit of wire insulation and all the sparking had burned the insulation partially off of 2 other wires in the bundle. Obviously things were intermitently shorting out between the wires of that bundle. I spliced the wires back together with connectors and heat shrink tubing and all is well.