Desperate for WIRING diagram Perkins 4108 on 1983 Beneteau First 38.5

Sep 30, 2017
4
Beneteau Beneteau First 38.5 1983 Miami Florida
Hello!

I am desperately looking for a wiring diagram for my Perkins 4108M marine engine s/n 37112990/1 mounted on a 1983 Beneteau First 38.5 Hull #672955. My main concern is the wiring for the Starter Motor and Alternator.

Any pointers to where I can get this information is welcome.

Thank you all for looking and answering.
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Found a shop manual here. The wiring is more explained than diagramed - so you need some imagination or experience maybe both. Keep in mind that Perkins does not make alternators nor starter motors so these items on Perkins will be very nearly the same as any other. Draw out your own diagram and you will be fine.

Anyway go to https://sbo.sailboatowners.com/dl/downloads.php. Then look at Perkins there are several shop manuals including the 4 108

Charles
 
Last edited:
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Oscar. You posted this twice.
Here was the answer on the "It's a Small World post..." ( https://forums.sailboatowners.com/index.php?threads/its-a-small-world.162679/#post-1403400 )

Perkins 4108M marine engine s/n 37112990
That is not the serial number it is a casting number for the block. The 4108 usually starts with the letter "A" to designate the the engine family or type. Here is a link to help find the Perkins serial number.
http://www.enginebuildermag.com/2009/11/perkins-engine-serial-number-information/
Here is the Perkins 4108 wiring diagram.
If you want all of the info regarding wiring Starter Motor and Alternator here is a great resource from our resident wizard...
https://forums.sailboatowners.com/index.php?threads/1-both-2-off-switches-thoughts-musings.137615/
155636682.jpg for the starter to a starter battery.
You will see in the MaineSail threads that alternators are best wired to the battery. as in this image.
large.jpg

How you manage the charging of batteries from the alternator is covered in volumes on this forum.

Hope this helps get you started and less PANICKED!!!​
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Yea, I get that, John, but I was wondering why the OP was desperate for it; I get the idea the engine won't start, no power to the starter. Was wondering if he ever started it. If not, suggest hold glow plug button while pushing start button.
 
  • Like
Likes: jssailem
Jan 21, 2011
2
balboa 26 26 hudson, fl
Hello, I did a big rookie mistake. I disconnected the wires to the ignition switch and did label them but the oil on wires let the tags fall off. I believe I have the original wiring harness. Can anyone tell me what color wires are supposed to be on which post? I have a 3 post switch. One says B, I, and S. After reading this forum, I now know the basic letters but there are several wires on a couple of posts. I found out how confusing wiring can be now. Hurt my back so crawling in the engine room looking at where the wires go is almost out of my ability (back). Any help is hugely appreciated! Mark 1977 Perkins 4108 in a 33 Morgan O.I.
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Wiring depends on functioning of your engine. There is a 4 pin and a 6 pin.
Guessing is not a good idea when making electrical connections. You really need to identify the wires source connections. Colors can be changed over the years so even wiring from manual images can be suspicious.

Here are the functions for the two switch types.
015787F9-A4C7-459B-AE06-A0E8C94AB675.jpeg 588C9074-2BDD-4F9C-9995-95552B746DA2.jpeg

099FCD7D-B00D-453B-874E-E0A1A4E173CE.jpeg 44136E77-09EC-497F-9767-466D17592883.jpeg

Hope it helps you and your back.