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jamesgangnc[_2_] jamesgangnc[_2_] is offline
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First recorded activity by BoatBanter: Mar 2008
Posts: 160
Default mercruiser ignition problems

On Jul 29, 9:34*pm, Tim wrote:
On Jul 29, 3:25*pm, aslappy1 wrote:

I have a 98 bayliner with a 3.0 mercruiser had a *problem on the water
the starter went. Had it towed fixed the starter and now it wont run. It
cranks and all but wont start. And the only plug that is firing good
enough to get across a plug is cyl 2. The others are getting enough
juice threw them to light a tester light but not strong enough to fire a
plug. My guess is its the ignition module and I have one on its way. any
ideas what it could be if that dosent fix the problem?


--
aslappy1


It could be the module, but it seems interesting that it ran until you
had a starter failure.


Put a volt meter on the 12v line going into the module and see what
you have while it's cranking. It seems unlikely that the module went
bad the same time the starter did. The merc thunderbolt modules are
extremely reliable. That it would have some spark does not point me
to the module first. It's doing the same thing for all 4 plugs. I'd
be checking the rest of the ignition first. But only afer I found I
was getting 8 to 10 volts at the ignition while cranking. If you
suspect low voltage you can also hook a second battery to the ignition
temporarily while you troubleshoot. It can be a smaller battery like
a riding mover, jetski, etc. Don't try it by substituting a charger
though.

Exactly what was wrong with the starter and what diagnostic steps did
you take before deciding to replace the starter?