Logo
FULL SITE MENU

2006 8.1 Horizon S electrical help needed.

O

outobie

Regular Contributor
Hi all hoping someone can point me a good direction. went to start boat for first time this year and it started up and idled perfectly. I noticed that stbd motor was reading battery voltage at the gauge on the helm and the gauge on the electric panel in the cabin and was not charging.

so I replace the alternator (old one was definitely shot) with a new OEM mercruiser alternator. now the boat wont start unless I push the emergency parallel switch. when I turn on the ignition i get nothing...zero volts on either gauge, batteries (brand new a week ago) test perfectly at 12.4 volts, I can start the engine by using the emergency parallel switch. once running voltage fluxuates from 14 to 15 volts (not good) otherwise it runs normally just having a charging issue.

I checked the ignition switches by swapping port for stbd and the problem did not move with the switch. I can't get any voltage to the ignition switch...I have battery voltage at the battery solenoid, and both battery switches.

where else can I check? I'm not getting voltage to my stbd ignition switch...is there a fuse somewhere for the ignition? I've been through the manual and can't find any fuses for the ignition on the boat wiring diagram...don't have a diagram for the engines.

one other data point...I forgot to disconnect my batteries when I swapped out the alternator and accidentally touched the battery lead to the engine bracket and caused a spark...thinking this may have popped something but can't figure out what.

It must be self inflicted from me changing the alternator but just can't figure out what to look at

thanks for any help!
 
I was wondering about the 90 amp fuse at the starter...the starter works just fine when I emergency parallel the engines...would the 90 amp fuse at the starter prevent voltage from reaching the ignition switch? I've got no STBD voltage at the helm, ignition switch red/purple wire or gauges or at the cabin STBD ignition switches or volt meter. I do have STBD voltage to the EIM systems, like the engine hatch openers and the helm electronics, GPS, etc. which run off of the STBD bank.


what path does voltage travel from the batteries to the ignition switch? I can't figure this out by looking at the schematics in the owners manual. looks like


I"ve got battery voltage at the alternator and at the battery solenoid, but not at the ignition switch.


Does anyone have the mercruiser engine wiring diagram for the starting / ignition circuits?

could the new alternator that has the fluctuating voltage be the cause of my issues?

 
starting at the starter, power comes from the battery cable .On this post is the battery cable and a plastic squarish block that has a Red and Orange connected together The REd is main system power and the Orange is the Alt wire.Accidently shorting out the alt or its output wire will blow this 90a link.
Check to see if the Red wire is connected at the starter
 
<img src="http://www.marineengine.com/boat-forum/attachment.php?attachmentid=26634&stc=1" attachmentid="26634" alt="" id="vbattach_26634" class="previewthumb"><br><br><br>you mean this?  I coincidentally just bought new ones...I thought they looked corroded and bent.  this pic is from 3 weeks ago before the trouble started
 

Attachments

  • starter 90 amp fuse.jpg
    starter 90 amp fuse.jpg
    281.2 KB · Views: 23
Last edited:
there should also be a 20 fuse, close the the ignition switch, in the RED/PUR wire connected to the BAT terminal at the ign switch...
 
I expected there would be a 20 amp in line fuse on the ignition like all my other Mercruiser had. I tore half the boat apart looking for one... there isn’t.

Ok did figure it out and correct the issue Bt Doctur was spot on... it was the 90 amp in-line fuse

niw everything it working perfectly again, it’s even charging properly

thanks for the help!
 
Back
Top