Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-02-2008, 10:00   #1
Registered User

Join Date: Nov 2005
Location: Myrtle Beach SC
Boat: Zack C bayliner 3870
Posts: 13
Could this be the problem?

In working on my gen set. A Westerbrake 7.6Kw which is on my 3870 the on, off, start knob broke off. I suppose as old as it was I should not be surprised. I took off all the wires and removed the switch and made a slot in the stub that remained sticking up. This way a small flat head screw driver works like a key and works just fine until I can find that part of the switch and replace it. When I wired it back up I may have made a mistake and if so would this keep the gen set from starting. In the on position I have power going to the fuel solenoid and pump, in the start position there is power to starter and it turns with plenty of rpm to start. Now here is where I could have a problem, but I am not sure. The switch has room for four sets of wires. In the off position I can pull down the spring loaded pre-heat switch and I can hear it engage at the gen set. In the on position it will not function. Would this cause the gen set not to start or should it start any way?
__________________

__________________
Bill
zackc is offline   Reply With Quote
Old 07-02-2008, 11:31   #2
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,153
Do you have any pictures? The fact that the preheat switch does not work in the run position should not prevent it from running. The preheat switch does not need to be working after the genset is running on its own.
__________________

__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 07-02-2008, 11:59   #3
Moderator Emeritus
 
Pblais's Avatar

Join Date: Mar 2003
Location: Hayes, VA
Boat: Gozzard 36
Posts: 8,700
Images: 15
Send a message via Skype™ to Pblais
Quote:
Now here is where I could have a problem, but I am not sure. The switch has room for four sets of wires.
With 4 wires you could connect them 6 different ways with 8 it's something like 33 ways. Asssuming two colors it's only 12 ways. There really is only one way that would be correct.

There is also the problem that the switch could be broken.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
Pblais is offline   Reply With Quote
Old 07-02-2008, 12:07   #4
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,153
Trace the wires to their origin so you know with certainty what wire does what and then "flag" them with white electrical tape and a Sharpee. Separate the key switch from the wires and test the individual terminals on the key switch for continuity with the key in all its positions. Draw it all out on paper. Go to the dealer and ask for an electrical schematic or where you might find one online. The original owners manual probably had an electrical schematic...check Ebay. Google the model number of your generator to find more information. Ask the dealer where you can purchase a replacement switch or its equivalent if the switch is bad. It should all make sense then and save you the cost of sending someone out at $95 per hour to move one wire from terminal A to terminal C.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 07-02-2008, 15:10   #5
Registered User
 
Beausoleil's Avatar

Join Date: Jul 2007
Location: Potomac Shores, VA USA
Boat: Formosa 51 Aft Cockpit Ketch - "Beausoleil"
Posts: 565
Images: 1
Bill,

Worth a look: check the fuse on the right side of the control box. I have a problem with our 7.6BTD. I don't have the wiring drawings with me (I'm at work), but our problem is that the genset will run for a few minutes, and then blow the fuse. It seems (from memory, anyway) that the engine cut-off solenoid is tied into the same pre-heat circuit somehow. For whatever reason, as the engine warmed up, some current was being shunted through the fuse. If I remember right, if the fuse is blown, trying to start it gives the same symptoms you're seeing - turns over fine but never starts. You might have accidentally blown the fuse while re-attaching the wiring.

Rather than have an electrician troubleshoot my problem(even though it's under warranty), since we're replacing the whole electrical system on the boat, I thought I'd just wait for the ratty wiring with breaking-down insulation to be replaced...

Wiring drawings are available here.
__________________
Beausoleil is offline   Reply With Quote
Old 07-02-2008, 18:34   #6
Registered User

Join Date: Jun 2005
Posts: 1,901
are we discussing the rotary switch on the lower helm station?
__________________
never monday is offline   Reply With Quote
Old 08-02-2008, 09:21   #7
Registered User

Join Date: Nov 2005
Location: Myrtle Beach SC
Boat: Zack C bayliner 3870
Posts: 13
Thanks for all the info. Yes I am refering to the lower helm station.
__________________
Bill
zackc is offline   Reply With Quote
Old 08-02-2008, 17:56   #8
Registered User
 
spencer53's Avatar

Join Date: Nov 2007
Location: Ventura Harbor, Ca.
Boat: Spencer 53 (Amazing Grace)
Posts: 77
You most likely have an oil pressure safety switch. It will cut off the fuel if oil pressure drops low. When starting, the preheat switch will override the oil pressure safety switch allowing fuel to the injectors. Once the engine starts, the oil pressure build allowing the preheat override to be released. Find that circuit and confirm that it is wired correctly and I am confident your problem will be solved.
__________________
spencer53 is offline   Reply With Quote
Old 08-02-2008, 19:09   #9
Registered User

Join Date: Nov 2005
Location: Myrtle Beach SC
Boat: Zack C bayliner 3870
Posts: 13
So, from what I am gathering here is that when the rotary switch for the gen set is in the on position the pre-heat circuit should be working, right?
__________________
Bill
zackc is offline   Reply With Quote
Old 08-02-2008, 19:20   #10
Registered User

Join Date: Jun 2005
Posts: 1,901
I had to go reread your post.
Yes, the preheat should work in the on position. The on position powers the pre-heat switch.
You should also get the solid clunk from the fuel cut solenoid in the on position.

Don't start chasing problems on the engine....you didn't mess with it to cause this problem.
Go to the Westerbeke (note spelling) site and download the wiring diagram for your unit. There are some weird special mandated circuits you need to be aware of.
__________________

__________________
never monday is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Eberspacher problem Capt Hook Plumbing Systems and Fixtures 3 08-02-2008 05:27
Serious problem bottleinamessage Electrical: Batteries, Generators & Solar 19 26-08-2007 11:39
Alternator problem JusDreaming Engines and Propulsion Systems 4 27-05-2007 15:41
Yanmar problem Tropic Cat Engines and Propulsion Systems 26 09-05-2006 13:35



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:24.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.