5.7 Merc wiring/ignition prob

[meek77]

Hey guys heres the run down,<br />1986 Four Winnns 211 Liberator, 5.7 L Merc 260 with Thunderbolt ignition. New starter, plugs, wires, coil, dist cap, rotor, and battery just this past week. My problem is when underway I switch on an Accessory switch such as the Nav lights or blower and the entire boat dies. I turn the key to off and put the boat back in neutral and it starts right back up. I believe with ignition switch is wired in with the accessory switches but i dont know what is going wrong because no fuses are blown. ANY advice would be greatly appreciated, its driving me insane.

 

[vipzach]

Re: 5.7 Merc wiring/ignition prob

Welcome to iboats!<br />Did you recently install or change anything?

 

[vipzach]

Re: 5.7 Merc wiring/ignition prob

wait a minute that sounds kinda dumb....I should have asked differently. Did you change all that stuff trying to fix the boat dieing problem?

 

[waterone1@aol.com]

Re: 5.7 Merc wiring/ignition prob

To really get to the bottom of this problem you are going to need a volt meter, so you can take reading at various points (such as at the ignition switch)and find where the voltage is sagging. A guess or two would be : loose or corroded connection at the starter main terminal. Corroded/loose connection of your engines multi-pin connector. Depending on the boat, there may be a 12V buss under the dash...look for loose/corroded connections.

 

[meek77]

Re: 5.7 Merc wiring/ignition prob

Hey thanks. All the parts i installed are identical to the old ones. The only other thing i can think of is the radio i installed last week as well. I wired it to an unused acc switch which is in the main series that also includes the ignition. I did notice that the radio displays "low battery" when underway. Since adding the new parts it doesn't display that anymore though. I'm going to check all the connections tonight.

 

[vipzach]

Re: 5.7 Merc wiring/ignition prob

Did you install all of that trying to fix the problem or another problem? Do you have a DVM? If so, check your battery voltage with the motor off and with the motor running(above idle). Also check all of your cables, maybe you have one with corrision in it.

 

[meek77]

Re: 5.7 Merc wiring/ignition prob

The work done was yearly maintanence, and yes i have a volt meter. I'm positive my power cables are good, just replaced the starter and battery. I'm thinking its short, i just dont know where. My other idea is if i could rewire the ignition switch so it is not connected to the acc switches and have it a separate circuit. Since teh wiring is still factory i'm thinking there must be a reason why the ignition is line with the acc switches.

 

[rbezdon]

Re: 5.7 Merc wiring/ignition prob

Sounds like a bad ground back to the electrical system. The ac load switched on drops the input voltage to the ignition module and shuts it down. It will shut down when the voltage goes low. Does it shut down if you trim while underway?? This is a very common problem and is almost alwas casued by corroded connections. Your boat is old enough to be riddled with bad connections, especially if your run in salt water.<br /><br />By the way, I hope you didnt put all that "every thing else" on MasterCard or it will be priceless at 19%APR!!!!

 

[meek77]

Re: 5.7 Merc wiring/ignition prob

It does not shut down while trimming, only when i flip ACC switches. You are on the same page that i am right now. All the connections behind the dash are spade connecters and yes i do run in the salty stuff so you're probably right. Thanks for the info.