200hp Venom electrical trouble..

[jstutz101]

So, I went to start the boat in the driveway. It hasnt been run in a month or so. I left a switch on a month ago which of coarse killed the battery. :facepalm:

So, I grabbed a trolling battery and jump started it. It started and all was well. I disconnected the jumper cables and for kicks grabbed a voltmeter and check to see if the engine was charging the battery, it wasnt. So, I turned the engine off and noticed the tilt/trim wouldnt work. Pulled the hood and found a 20 amp fuse tucked under a red cover that was blown. Replaced the fuse and got tilt/trim back. For kicks I turned the key to on and noticed no alarms or lights. Check the fuse - Its blown again... :faint2:

Replaced the fuse again tilt/trim yes, turn key to "on" - no alarms,blown fuse, and no tilt/trim. (Yea, it takes me awhile to catch on) Any idea where to start? Odd that everything started out fine and now I'm blowing fuses.

Any help is appreciated!

Jeff

 

[glenn property of pam]

Re: 200hp Venom electrical trouble..

don't turn the key on when connected to a flat battery. Replace the battery then see what happens

 

[jstutz101]

Re: 200hp Venom electrical trouble..

don't turn the key on when connected to a flat battery. Replace the battery then see what happens

If its something that simple that would be great!

Thanks!!!

 

[glenn property of pam]

Re: 200hp Venom electrical trouble..

V=I*R. R (resistance) is constant so when V (volts) drops I (amps) increases. 3amps at 12v = 6amps at 6v = 12 amps at 3 volts.

So you really need 12v or the trim system will pull a massive amount of current at low voltage

Im not saying this is your only problem but you can not test until you replace/full charge the battery

 

[daselbee]

Re: 200hp Venom electrical trouble..

V=I*R. R (resistance) is constant so when V (volts) drops I (amps) increases. 3amps at 12v = 6amps at 6v = 12 amps at 3 volts.

Glenn buddy...I am sorry, but that is just not right. If voltage drops, current drops too. Nothing says that your V=I*R equation must remain constant. Absolutely true....V=I*R, so therefore solving for I gives I=V/R. So, now take the values of say 10 ohms and 12 volts, plug it in solving for I and you get 1.2 amps. Now, just change V to 6 volts, and you get what? 0.6 amps for I. His problem is NOT as you have assumed regarding some sort of Ohms law that describes a constant. Ohms law does not. Secondly, the current drawn by the T&T motor is not fused. The switching that controls the relays is, but the actual motor current is not. The fact he has no T&T when fuse is blown is because the relays will not pick. To debug this, I would wire in a 12v automotive bulb in place of the fuse. Then when key ON, if there is a short, the bulb will glow bright. Trace the red/purple wires thru harness, and the purple wire at the key switch looking for shorts to ground, chafing, etc. Maybe right at the key switch itself.

 

[jstutz101]

Re: 200hp Venom electrical trouble..

Is there a way to bench test my voltage regulator/rectifier? I've got a mulitmeter. I've tried figuring out the shop manual but the electrical section is confusing.

 

[jstutz101]

Re: 200hp Venom electrical trouble..

FIXED!!!! A few hours and 8 or so fuses later I isolated my short to a bad Tach. Whats a good brand of tach to get??