Have an old 78' Mark Twain OMC with the 351w. Orange wire going to the ignition has a inline 20a fuse that has blown before. It did it again so I put another fuse in it & it blew right away. I am sure there is a grocery list of things it could be.
The ignition circuit should be a 20 amp fuse. It goes from key to coil, alternator, automatic choke, ESA and gauges. It is the circuit which powers up everything.
Start by disconnecting things and reconnect one by one until it blows
Ok so I figured out that it has something to do with the fuel sending unit. I just put installed this sending unit. There is really no way to hook it up wrong! Hot wire in the center & the ground. Checked out continuity on everything and all is good. Even run the tester from the hot wire to a ground to see if it was possibly grounding out somewhere. Everything fine there too. When I check the voltage of the hot wire (pink) that hooks up to the hot side of the sending unit I get 7.57V. What do I have wrong here?
Blew another fuse without the sending unit being hooked up, so that pretty much knocks that out as being the issue. Outta time this weekend so I will dig into it next weekend again. Another issue is this boat is so old that some of the wiring as been messed with over the years. Not all of the colors are as what the shop manual states. :grumpy:
