Like Tree0Likes

Starting issue 89' 350 OMC Cobra

Reply
Old 10-16-2012, 07:27 PM
  #1
Fast Singles Club
Gold Member
Thread Starter
Trade Score: (8)
 
the deep's Avatar
 
Join Date: Oct 2011
Location: Raystown Lake , Pa.
My Boats: 99 Warlock 25'SXT Cat " Lunatic Fringe "
Posts: 3,563
Default Starting issue 89' 350 OMC Cobra

Brother in laws boat only wants to start when you let off the key after cranking . When it decides to start it runs great . Installed new ignition switch , tuned engine , new fuel pump and water separator and removed check ball from tank . I suspect the resister wire has gone south but did not get a chance to put a meter to it . Anyone else run into this problem ? Any suggestions would be appreciated . Problem is the same if engine is warm or cold .
the deep is offline  
Reply With Quote
Old 10-17-2012, 08:32 AM
  #2
coolrunning racing
VIP Member
 
mrv8outboard's Avatar
 
Join Date: Feb 2001
Location: cape cod
My Boats: built myself 1994
Posts: 528
Default

Your symptoms point to no key on power to the ignition coil. There is a start/run bypass circuit that energizes the ignition coil during crank, so it will start but let off the key and it dies. You can test it with a jumper wire from B+ to IGN on the coil and it should run.

Now what are the possible causes? Your first thought of ignition resistor. Also the shift switch or module. A test light or better a VOA meter and test it.
mrv8outboard is offline  
Reply With Quote
Old 10-17-2012, 12:20 PM
  #3
Fast Singles Club
Gold Member
Thread Starter
Trade Score: (8)
 
the deep's Avatar
 
Join Date: Oct 2011
Location: Raystown Lake , Pa.
My Boats: 99 Warlock 25'SXT Cat " Lunatic Fringe "
Posts: 3,563
Default

Quote:
Originally Posted by mrv8outboard View Post
Your symptoms point to no key on power to the ignition coil. There is a start/run bypass circuit that energizes the ignition coil during crank, so it will start but let off the key and it dies. You can test it with a jumper wire from B+ to IGN on the coil and it should run.

Now what are the possible causes? Your first thought of ignition resistor. Also the shift switch or module. A test light or better a VOA meter and test it.
Thanks . Problem is it does not fire while cranking , only wants to fire when you release the key to the run position . I checked to make sure the ignition interrupt system is not activated while shifter is in neutral . I did put a test light to the + coil terminal and it shows power while cranking and when the key is in the run position . Seems like the running starter motor has something to do with this . I have never run into this problem before . Thanks again for your help .
the deep is offline  
Reply With Quote
Old 10-17-2012, 10:26 PM
  #4
Fast Singles Club
Gold Member
Thread Starter
Trade Score: (8)
 
the deep's Avatar
 
Join Date: Oct 2011
Location: Raystown Lake , Pa.
My Boats: 99 Warlock 25'SXT Cat " Lunatic Fringe "
Posts: 3,563
Default

Anyone ? Before my fix is a hole in the bottom !
the deep is offline  
Reply With Quote
Old 10-18-2012, 01:11 AM
  #5
Platinum Member
Platinum Member
Trade Score: (3)
 
mike tkach's Avatar
 
Join Date: Oct 2007
Location: yorkville,il
My Boats: 31 american offshore,38 fountain fever
Posts: 8,119
Default

i would check the voltage at coil while cranking with a digital volt meter,instead of a test lite,this way you will know exactly how much voltage the coil has while cranking,if it is to low,the spark might be weak.
mike tkach is offline  
Reply With Quote
Old 10-18-2012, 01:41 AM
  #6
Registered
 
Join Date: Mar 2009
Location: OFallon,Mo.
My Boats: 83' Nordic 23' Viking 505 BBC TRS Drive
Posts: 1,690
Default

There's a wire that runs from the starter solenoid to the coil + that provides full voltage to the coil during cranking only. When you release the key it no longer supplies full voltage to the coil but then gets reduced voltage through the resister wire. Sounds like nothing is wrong with the resister wire. On a merc it's a Purple/Yelo wire. Don't know what color it would be on an OMC.
picklenjim is offline  
Reply With Quote
Old 10-18-2012, 02:28 AM
  #7
Registered
 
Join Date: Dec 2009
Location: orange county, ca
My Boats: searay p22
Posts: 29
Default

i would suspect the ignition switch itself contacts could be gummed up or if it has been replaced may be wired incorrectly. i had changed the tach out and reversed 2 wires it took me an hour to figure out what i did. hotwire it an drive it like you stole it
jbones98 is offline  
Reply With Quote
Old 10-18-2012, 09:39 AM
  #8
coolrunning racing
VIP Member
 
mrv8outboard's Avatar
 
Join Date: Feb 2001
Location: cape cod
My Boats: built myself 1994
Posts: 528
Default

Okay, my mistake. There is a start/run bypass wire the is connected to the starter solenoid IGN terminal. It is one of the small terminals. The yellow with the red tracer lead is crank voltage, so it would be the opposing terminal. During crank the starters high amp draw pulls all the battery voltage to the starter, leaving very little for everything else. So they tap off the solenoid where all the power is going during crank to energize the ignition with no resisted battery voltage. So test that circuit, first at the solenoid (starter mounted) with the wire disconnected, then the wire to the coil.
mrv8outboard is offline  
Reply With Quote
Old 10-18-2012, 11:26 AM
  #9
Fast Singles Club
Gold Member
Thread Starter
Trade Score: (8)
 
the deep's Avatar
 
Join Date: Oct 2011
Location: Raystown Lake , Pa.
My Boats: 99 Warlock 25'SXT Cat " Lunatic Fringe "
Posts: 3,563
Default

Thanks guys , will do .
the deep is offline  
Reply With Quote
Reply



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 -5. The time now is 05:16 AM.


Copyright 2011 OffShoreOnly. All rights reserved.