Ignition

[93ultra]

I have a 95 Wellcraft Martinique with twin 454's. One of the motors has started dying after a few minutes of running. When I first start it, it runs great and then after a few minutes the tach and the volt guage begin jumping around the motor starts sputtering, backfiring and eventually dying. If I let it sit for a while I can get it to start back up only to repeat the process. I have checked the fuel and filter all is fine. I have trplaced the coil and the ignition mod and the cmb. I'm at a loss anyone have any other thoughts? It's a merc with thunderbolt V ignition system.

 

[HT32BSX115]

Re: Ignition

Howdy,

It's a merc with thunderbolt V ignition system.

One of the best ignition systems ever put on a marine engine!




Anytime the voltage "jumps" around or gages start acting sporadically, you most likely have an electrical problem, NOT an ignition problem (although with electronic or electrical ignition, an electrical problem can be the cause of an "ignition" problem......Unless you're running a magneto!!)


You need to check all the ground connections on both engines and all the batteries.

Also check the + (plus) connections at the batteries and all other power connections.


This includes all the crimp type connections, not just the nuts that hold them on. Corrosion can cause crimped connections to fail intermittently. Any loose hardware at a power OR ground connection can cause electrical power loss too!



Regards,



Rick

 

[dsiekman]

Re: Ignition

Try swapping the ignition modules and see if the same engine has the issue or if it suddenly moves to the other engine. My old boat had a design flaw where as water would drip from the sun pad/engine cover right on top of the dist. cap and ignition module. It eventually shorted out. For the most part it would idle but would sputter and die under load. Of course, it wouldn't do it to me until I was a good 10-15 miles from my slip.

 

[93ultra]

Re: Ignition

Thank you I will check that out this weekend.

Tim

 

[93ultra]

Re: Ignition

After swapping parts from bad running motor to good motor I think I have narrowed it down to the ignition sensor assembly. I ran the motor for several minutes up to operating temp and couldn't get it to stall but I haven't tested it under a load, thats coming next.