Electrical Short, Possible Voltage Regulator - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Electrical
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 06-20-2003, 07:29 PM
Registered User
Last photo:
Join Date: Jul 2002
Location: Sacramento, Calif.
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Electrical Short, Possible Voltage Regulator

I have a ski boat with a 455 Olds engine. The engine has 283 hours and has been garaged since it was purchased. The alternator (original) is a Motorola with an external voltage regulator. Here is my problem...when accelerating and maintaining a decent speed other than an idle the gauges will start to bounce back and forth. At this time the engine goes dead. There is only one fuse under the dash and that gets blown. Once I replace the fuse the engine fires up and continues on. A little while later the same set of circumstances, blown fuse. I went to my local boat repair shop and they made several recommendations. I replaced the ignition switch, the coil and ballast. This did not cure the problem. I looked under the dash and have a clear view of all wires. None were touching the other, no bare wires whatsoever. All wires going to the engine are in good condition no breaks in the insulation either. I took the alternator off and had it bench tested. The first place could only test the alternator not the voltage regulator. He said the alternator was fine. I went to the second place he bench tested the alternator and voltage regulator and said both components work fine. I replaced the amp meter and then took the boat out and had no problem. Several hours later the problem came back. I replaced the fuse and turned the ignition key on and the fuse would blow before the engine would start. Replaced the fuse and it got blown again. This happened several times and I had to be towed in. I went back to the boat repair shop and another mechanic told me it was the starter that was shorting out. He didnít elaborate only telling me how much it would cost to research the problem at $75.00 per hour. The starter works fine no indication of going bad whatsoever. I have been told that even though taking the alternator off of a boat and/or car and having it bench tested doesnít necessarily find the problem. I am wondering if the voltage regulator is intermittently going bad. Any input would be greatly appreciated. Thank you.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 06-21-2003, 12:13 AM
horvath's Avatar
Acoustic Rock ... for real.

Last journal entry: About Fusible Links
Last photo:
Join Date: Feb 2003
Location: Central New Jersey
Age: 66
Posts: 1,983
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Sounds to me like SOMETHING is wired wrong!

The question to answer is, "What is blowing the fuse?"

You can bench test forever, and with the unit wired properly on the bench, of course, everything checks okay.

Your wires and all look fine because the fuse keeps saving them for you.

Check ALL your wiring.

54 Chevy Pickup
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-21-2003, 01:13 AM
2-manytoyzs's Avatar
Start those projects someday

Last journal entry: Divco - has been on the back burner
Last photo:
Join Date: Dec 2002
Location: Fresno
Age: 67
Posts: 557
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I would find it hard to believe the starter is at fault. Its out of the system unless its engaged.
Motorola charging systems are difficult and expensive to repair and maintian. Personally, I would junk the alt in favor af a 1 or 3 wire internally regulated GM alt. Lots of info in the knowledge base about that. I put a 77 chev PU alt in my commando and got rid of the Motorola and its soooooo much better.
If its currently blowing fuses, it should be fairly easy to find. Remove the fuse and install a test light in place of the fuse, then start disconnecting stuff until the light goes out. Do a wiggle test of all the wires and see if you can get the light to get very bright. The light will already be on, but when the short developes, it will get real bright. Intermittant shorts are not the easiest things to fix.
Reply With Quote Quick reply to this message

Recent Electrical posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may 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 -6. The time now is 09:48 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.