Starter issue or Starter 90Amp fuse issue?

[Boater71]

I've been having issues with STBD engine stalling at idle after a full day of boating. Low voltage error. I used a voltmeter and got he following results:

Key is in OFF position, batteries on

• Voltage at alternator is 13.3V
• Voltage form the 50 amp fuse is the same
• Voltage going to stater is the same

Key in the ON position, but boat has not started (i have a push button start), batteries on

• Voltage going to stater is the 13.7
  
• Voltage from the 50 amp fuse is 8.87 to 9.06 V
• Voltage at alternator (Orange wire) 8.87 to 9.06

I could not get to the starter as it is a very tough squeeze. Any thoughts here? What should my next step be? I called my mechanic and he said to replace starter, you would have to take out the manifold.

Thank you in advance.

 

[Boater71]

does anyone have the wiring diagram for starter on this engine?

 

[scoflaw]

Clean up those connections first. 90 amp fuse/grounds

 

[Bt Doctur]

sounds like corrosion at the 90A block.
battery cable and fuse block to mani posy, yellow/red to inboard small post, Alt Orange and system power Red may be connected together, an option I dont like. If the 90 blows your dead in the water unlike having the Red wire directly to the battery and it being protected bu the 50 A CB

 

[Boater71]

sounds like corrosion at the 90A block.
battery cable and fuse block to mani posy, yellow/red to inboard small post, Alt Orange and system power Red may be connected together, an option I dont like. If the 90 blows your dead in the water unlike having the Red wire directly to the battery and it being protected bu the 50 A CB

I will check it out next couple of day if i can get down there (have to find a way)

 

[Boater71]

at boat today, had to remove the manifold, riser and elbow to have decent access. Defiantly the 90A looks corroded and even melted!!! I was wondering how the boat was running!!!

 

[Boater71]

I changed the starter and 90A. voltage now at the alternator is the same as the battery and the original 90amp corroded enough but seems functional. I started the engine rev to 2000 rpm. The voltage at the alternator went all the way to 13.4 - 13.7, but not 14.2 like the other engine. Before changing the starter and 90A, the STBD would always stay around 14.2. I have not tested the boat in open water yet, This was just revving the engine at the dock. I always compare the port and STBD. Here is what i got:
Key in and On position
- STBD 12.7
- Port 12.7
engine started:
- STBD 12.7
- Port around 14.2

Revving up to 2000 RPM:
- STBD 13.4 - 13.7
- Port 13.7 - 14.2

Is this normal or do I have another short which i need to troubleshoot?

I did clean with a copper brush all the connections involved and applied Dielectric grease to all the connections.

 

[CaptRonn]

Does your boat have a battery isolator? Have you checked it?

 

[Boater71]

Does your boat have a battery isolator? Have you checked it?

not sure and where would it be ?

 

[CaptRonn]

not sure and where would it be ?

Do you have an owners manual with a wiring diagram? Look there. Also, the isolator should be located near the batteries.

I'm not familiar with your boat model.

 

[scoflaw]

13.7 is an acceptable value.

 

[Boater71]

Do you have an owners manual with a wiring diagram? Look there. Also, the isolator should be located near the batteries.

I'm not familiar with your boat model.

i looked at the manual and did a search, but nothing on Battery Isolator. the only reference is if auxiliary batteries are installed, which in my case the boat does not have aux battery. I have an emergency start which combines voltage form all 4 batteries if one is low.