Mercruiser 165 Starter Fuse and Engine Circuit Breaker Help

[59Thompson]

1971 Mercruiser 165, the operator manual and parts book show a 40 amp circuit breaker on a plate for the engine and big fuse for the starter. But they don't show any wiring information or details of how to hook them up. I have the wiring diagram, attached here, but I don't see them on it unless I'm missing the symbols. Any help and pics would be greatly appreciated.

 

[alldodge]

how about these

 

[59Thompson]

Wow Thanks for the quick response. That gives me what I need to know for the circuit breaker. Do you have anything that shows the fuse and rating for the starter?

 

[alldodge]

Starter doesn't have a fuse on it
In later years when they got rid of amp meters they started installing a 90 amp fuse between ALT and BAT

 

[Bt Doctur]

But where they went wrong was tying in the engines main system at that same point. blow the fuse and your dead in the water . I rewire the system power direct to the starter post, it``s protected by the 50 CB You donr need a 90A infront of it . Now if the alt shorts and blows the fuse you only lose the chagrging system but the motor will start and run

 

[Bondo]

Ayuh,..... I think that 90a fuse might have some usefulness with the Efi's, 'n Mpi's, but is useless with a carbed motor,....

Hence my nickname for it, the Lawyers fuse, nothin' but a CYA kinda thing,....

 

[59Thompson]

Gents, Just for clarification so I will need to establish a 40 amp circuit breaker with 40 amp capable red wire from the left terminal on the solenoid through plug terminal 6 up to the red terminal on the ammeter. Is that correct? I suspect and hope I may find the original wires when I get the mess cleaned up but I don't see that plate or original breaker. The alternator is the original 42 amp screened one with internal voltage regulator.

 

[alldodge]

Correct
Could also update to new design

 

[59Thompson]

Alldodge, I'm not sure what you mean update to new design. Do you have some pics? Blue Sea has a 40 amp breaker and was thinking about using that and appropriate wire to accomplish this. Also, and should I start a new thread: Every switched circuit seems to be always active with no fuse i.e. only the fuel gauge requires ignition on. The auto bilge pump has an inline fuse off the battery and is manually switched as well. FWIW seems odd there's no fuse panel either, it has a terminal board with the horn and a radio hooked to it. Trim pump has its own solenoid also. Thinking it might be smart to use one of the Blue Sea fuse boxes for most stuff after I clean this nest up.

 

[alldodge]

New design as in using current wiring standards. Can get a harness for engine and helm, but cost some coin.

Get rid of the Ampmeter and install a voltmeter.

Something like this, and it has TBV ignition but could be used with points



Custom Harness
Engine
https://www.hardin-marine.com/p-13230-custom-mercruiser-style-engine-harness.aspx

Helm
https://www.hardin-marine.com/p-13227-universal-mercury-plug-harness-20-ft.aspx

 

[59Thompson]

Alldodge, Thanks!