1996 Mercruiser 5.7L misfire/no run issue...ignition module?

jprkcr97

Cadet
Joined
Jun 21, 2010
Messages
9
Hi, I have a 1996 Bayliner with a 5.7L Bravo engine. I bought it not running and replaced the engine and rebuilt the lower unit/outdrive. I have maybe 5-6 hrs on it so far. Last year it died at the dock and wouldn't restart. I got it out this year and managed to get it to start and run. Took it for first run of the year yesterday. All was good except it had a misfire at full throttle, as I had noticed before. Then when I throttled back to idle and coasted down, it died again and won't restart. I sprayed starter fluid directly into the carb and had no effect so I'm pretty sure it's ignition related. I also have a fuel pressure gauge and it showed good pressure. I checked wiring and all looked good. Didn't have a spark tester with me. Last year I noticed the tach jumping around strangely so replaced that also. Again, I'm suspecting the ignition module, but I can't seem to locate one for replacement. It says it's part "807645-3 57L BRV" and has a single plug with 8 pins (see pictures) Does anyone know of a replacement or different system I can install?IMG-2280.jpgIMG-2281.jpg
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
49,574
Use the Thunderbolt trouble shooting steps located in the stickies at top of the forum
 

jprkcr97

Cadet
Joined
Jun 21, 2010
Messages
9
Of course, today I put it back together in order to follow the flowchart and it started right up...
 

Fun Times

Moderator
Staff member
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May 16, 2009
Messages
9,048
The probability seems low that the ICM will be the overall issue but I'll throughout (to help with the overall question) that Merc did do a conversion kit because your original is no longer available but it seems they stopped with the kit as well as it says no longer available.. That mentioned there may be one kit left for sale on ebay that would fit your engine, https://www.ebay.com/itm/3547803204...4oKipiJXaAhdQfryCwtWMSR3tz|tkp:Bk9SR8DRn5SIYg

I believe yours may have a ground wire going to the ICM mounting case, Make sure the wire is clean and tight if so, along with all the other wires.

May have an issue with the distributor sensor under the cap to consider, number 6, https://www.mercruiserparts.com/bam/subassembly/31863/1939/50

Need your engine serial number to confirm but this might be your overall parts guide, https://www.mercruiserparts.com/5-7l-2-bbl-gm-350-v-8-1996-0f601000
 

jprkcr97

Cadet
Joined
Jun 21, 2010
Messages
9
The probability seems low that the ICM will be the overall issue but I'll throughout (to help with the overall question) that Merc did do a conversion kit because your original is no longer available but it seems they stopped with the kit as well as it says no longer available.. That mentioned there may be one kit left for sale on ebay that would fit your engine, https://www.ebay.com/itm/354780320470?epid=1250217872&hash=item529a8e12d6:g:AYYAAOSwoSNkXkhH&amdata=enc:AQAIAAAA4N/KU2weucEBgLvBETodqNswRBSgkjkO7KKzZhmxCXrZdYspOA10qhwHSVgblD7aD3JgBg2TXRbv9HbEriH6r869mcYzCAOJQpEPo347GmrHfkhNUZfIEcCJ6o/AwSQ3kndGIczVlDAqYrdmCMTFDvK7d2g6lZGtckliZWeyzNeVnzKz2oJ2newnHWi+FbkokX/rS+mQOuW8Kczu6KGdbz/7yQXAqedOiUjzR2PYtZG/igQZWeth2nH/yjlf51SgB7vG0RSAKP0N+eB0Kg4oKipiJXaAhdQfryCwtWMSR3tz|tkp:Bk9SR8DRn5SIYg

I believe yours may have a ground wire going to the ICM mounting case, Make sure the wire is clean and tight if so, along with all the other wires.

May have an issue with the distributor sensor under the cap to consider, number 6, https://www.mercruiserparts.com/bam/subassembly/31863/1939/50

Need your engine serial number to confirm but this might be your overall parts guide, https://www.mercruiserparts.com/5-7l-2-bbl-gm-350-v-8-1996-0f601000
Thanks for the info! My serial number is 0F793474 . I ordered the DUI system. Supposed to replace the coil and controller in 1 pkg. https://www.summitracing.com/parts/dui-m12720bk
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,443
In addition to what was listed if it happens again above try disconnecting the tach wire (grey) at negative post of the coil. If you were having tach issues a tach can kill the ignition.
 
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