Yamaha Outboard Parts
Yamaha   Yamaha Outboard Parts
Yamaha Outboard Forum Yamaha Outboard Parts Discussion Forum Yamaha Outboard Parts Boat Parts Yamaha Outboard Forum Outboard Motor Parts Contact Us
Yamaha Parts

Go Back   Yamaha Outboard Parts Forum > General Discussion > Yamaha Outboard Forum

LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 09-13-2017
Junior Member
Join Date: Jun 2017
Posts: 10
Default Clarification about the manual's terminology Yamaha 30DEO

I have a 2stroke yamaha model 30DEO.
6J8K - L - 1003853
6J8-D0 Model 2004

1. I cannot understand what the service manual means with the terms "circuit" and "loaded" in the charging system chapter.


2. I've put a new 45Ah battery to my outboard and in 3500 rpm I measure a 12.9V on the battery. Is this voltage low or ok ?
According to the calculation in the picture is ok ... but I need a second opinion.

Before I start my motor the volatage on the battery was 12.6V.
Reply With Quote
  #2 (permalink)  
Old 09-13-2017
Senior Member
Join Date: Jul 2013
Posts: 8,332

Thanks for providing the details about the engine. It helps us help you.

First know that Yamaha service manuals, IMO, are crap when it comes to explaining the product, how to test it, and what values should be seen. I understand your confusion. But, it is what it is.

There are many circuits within an electrical system. An electrical circuit. With respect to the charging system there is first the "lighting coil" circuit that provides AC voltage to the rectifier. Then there is the "rectifier" circuit that provides DC voltage to the battery. The battery cables and the battery are sort of a circuit.

Loaded means that what ever is being tested is connected to the system. For instance, a rectifier connected to a battery is considered to be loaded. If the wiring to the battery is disconnected then it is not loaded. A lighting coil connected to the rectifier is loaded. If the lighting coil is not connected to the rectifier it is not loaded.

The SM is telling you to check the output of the rectifier. See if it meets the specifications at three engine RPM's. There is no comment made about the system being loaded so the inference is to test it in the unloaded condition. That is, not connected to the battery.

For the lighting coil the SM is saying to test it in the loaded condition. That is, the lighting coil is to be connected to the rectifier.

The SM says to check for peak volts. Is that what you are doing? The voltage you report of 12.9 volts seems low. Note that the SM says it should be 20 volts. Maybe the battery is connected or maybe you don't have a meter that measures peak volts.

Since the rectifier output is on the low side did you measure the lighting coil peak voltage output? If so, what were the values?

Last edited by boscoe99; 09-13-2017 at 10:06 AM.
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 07:11 AM.

Outboard Parts

Other Forums
Mercury Parts
Suzuki Parts
Evinrude Parts
Johnson Parts
Honda Parts

Copyright 2000 - 2017, Outdoor Network LLC