Issue Starting Maxum 2400 SCR

[mmwjr]

Originally Posted by mitcheaton

Hey Mike, ill take a look this week. I already replaced the ignition switch with a new one.

Understand but sometimes new is bad.

[mitcheaton]

Interesting. Ill run your checks you posted above.

[donald]

12 v is just telling you that you have 12v, not if you have the amperage to do what you want.
Check all connections as you may have a high resistance somewhere.
Battery cables (+ and -), - on back of engine block, etc.
Don

[mitcheaton]

Hey mike. Touching purple and r/p together I get 0 volts. Same as when it was connected to the ignition switch. When the key is off I get 12v at the B terminal. When the key is in run I lose voltage at B and I terminals. However at the breaker where b connects I still get 12v in run. I just replaced the emergency shutoff switch same issue. I thought that was going to be it since that switch cuts power to the purple wire. I’m really at a loss here. When the key is in run I also get 0v at purple on the starter. In the diagram I have, all gauges and the alarm runs through purple. Does purple from ignition run directly to the starter? Or does it go through all the gauges first?

Also you mentioned a fuse somewhere? I don’t see any fuses connected to red purple or purple at the helm. There are several fuses close to the battery but they seems ok. The only fuse I see at the helm is for the cb.

[mitcheaton]

https://www.dropbox.com/s/9c134p8nqc...4317.jpeg?dl=0

https://www.dropbox.com/s/2dij8v92ci...4316.jpeg?dl=0

Here are the 2 electrical diagrams I got with the boat. It seems like purple is connected to a lot. If theres a short in anything connected to it, could it cause the issue im having?

[donald]

i still think you have high resistance somewhere, I would take the round plug at the engine apart and check for corrosion.
Don

[mitcheaton]

Originally Posted by donald

i still think you have high resistance somewhere, I would take the round plug at the engine apart and check for corrosion.
Don

The wiring harness plug?

[mmwjr]

The switched purple provides power to the ignition system as well as power to the gauges. I would disconnect the purple from each gauge one at a time until you get 12V on the I terminal. I bet you have a faulty gauge and it’s internal resistance limits the current which is why the fuse hasn’t blown.

[donald]

Yes the big wiring harness plug.
Don

[mitcheaton]

Originally Posted by mmwjr

The switched purple provides power to the ignition system as well as power to the gauges. I would disconnect the purple from each gauge one at a time until you get 12V on the I terminal. I bet you have a faulty gauge and it’s internal resistance limits the current which is why the fuse hasn’t blown.

I will give it a shot today. Which fuse are you referring to?

Thanks, Mitch

[mitcheaton]

Originally Posted by donald

Yes the big wiring harness plug.
Don

I hope its not the wiring harness. im 6'3 and its nearly impossible to get to in the crawl space. Ill check the gauges first, and if its not that ill start there. Thanks!

[mmwjr]

Originally Posted by mitcheaton

I will give it a shot today. Which fuse are you referring to?

Thanks, Mitch

It’s probably in the fuse block under the helm and is either 15 or 20 amp, however since you are getting 12V on the B wire the fuse is good.

[mmwjr]

Originally Posted by mitcheaton

I hope its not the wiring harness. im 6'3 and its nearly impossible to get to in the crawl space. Ill check the gauges first, and if its not that ill start there. Thanks!

The engine harness connector is on top of the engine near the distributor. A corroded or not fully seated connector will result in a voltage drop under load.

[mitcheaton]

Originally Posted by mmwjr

The engine harness connector is on top of the engine near the distributor. A corroded or not fully seated connector will result in a voltage drop under load.

i think first ill test voltage to the shutoff switch, removing the 2 purples from the switch, and testing the one coming from the dash to see if i have 12v. that should tell me if the issue is at the dash or the harness right? i.e. if im getting 12v at purple coming from dash to switch the issue is likely the harness?

[mmwjr]

Originally Posted by mitcheaton

i think first ill test voltage to the shutoff switch, removing the 2 purples from the switch, and testing the one coming from the dash to see if i have 12v. that should tell me if the issue is at the dash or the harness right? i.e. if im getting 12v at purple coming from dash to switch the issue is likely the harness?

Not sure I’m following you nor you have the flow correct. The harness provides power the the fuse box so the only issue it may have is a resistive contact that drops voltage under load. The purple is the output from the ignition switch so if you disconnect the wires from the switch the gauges will not have power. Where are you located?

[mitcheaton]

Originally Posted by mmwjr

Not sure I’m following you nor you have the flow correct. The harness provides power the the fuse box so the only issue it may have is a resistive contact that drops voltage under load. The purple is the output from the ignition switch so if you disconnect the wires from the switch the gauges will not have power. Where are you located?

Ah I see what you mean. Ill start with the gauges one by one. im in Portland OR.

[wiigelec]

It sounds like rather than a short you have an open wire somewhere.

What reference are you using to check voltage ie where are you putting the other lead of the volt meter? When you check voltage across an open switch you get 12V, when you check voltage across a closed switch you get 0V. I’ll have to look at the wiring diagrams you posted and catch up to what you’ve already tested.

[mitcheaton]

Originally Posted by wiigelec

It sounds like rather than a short you have an open wire somewhere.

What reference are you using to check voltage ie where are you putting the other lead of the volt meter? When you check voltage across an open switch you get 12V, when you check voltage across a closed switch you get 0V. I’ll have to look at the wiring diagrams you posted and catch up to what you’ve already tested.

Im using the ground into the fuse box under the helm for the other lead. Im using the 2400 SCR wiring diagram(laminated one). Its the exact same as to what i have. Im going to test the gauges. I have to believe something shorted. The boat idled fine for 10 minutes. I turned off the engine to check something, went to start again and nothing. The purple wire coming from the ignition switch splits off to all the gauges and then runs to the shutoff switch and then to the starter. I have to believe something in the dash popped but i have been wrong before.

Thanks!

[mitcheaton]

Originally Posted by mmwjr

Not sure I’m following you nor you have the flow correct. The harness provides power the the fuse box so the only issue it may have is a resistive contact that drops voltage under load. The purple is the output from the ignition switch so if you disconnect the wires from the switch the gauges will not have power. Where are you located?

just so i have this right. The harness goes to the fuse box, the red/purple goes from box to ignition switch, the purple goes from ignition switch to the gauges, then the shutoff switch, then the starter?

[mmwjr]

Originally Posted by mitcheaton

just so i have this right. The harness goes to the fuse box, the red/purple goes from box to ignition switch, the purple goes from ignition switch to the gauges, then the shutoff switch, then the starter?

Almost. It doesn’t go to the starter but to the + terminal on the ignition coil as well as ignition module.