4.3L No Spark

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poconojoe

Lieutenant Commander
Joined
Sep 10, 2010
Messages
1,966
First time starting the boat this season. On muffs in driveway. Had no problems last season. 2003 Mercruser 4.3L serial# OM643729 getting fuel into carburetor, but no spark. I pulled a spark plug and plugged it's wire back onto it. Grounded the casing and got no spark. I have continuity between the terminals of the circuit breaker atop the engine. With the key in the on position I have 11.82 volts on both sides of the ignition coil. When I tried to pull the high voltage wire off the coil, I noticed the boot was a bit melted. Some of it dripped onto the top of the coil. I peeled the boot off but can't seem to pull the wire out of its socket. I didn't want to force it out just yet. So, obvious signs of overheating here. How do I test the ignition coil output? Can I just get a coil from an auto parts store? If so, what do I ask for? 2003 Chevy 4.3?
is there anything else that comes to mind that may be the culprit?
thanks,
Joe
 
alldodge

alldodge

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Mar 8, 2009
Messages
42,537
V6 with TKS carb and TB-V ignition.
Run thru this first

TBV Troubleshooting.jpg
 
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poconojoe

Lieutenant Commander
Joined
Sep 10, 2010
Messages
1,966
ALLDODGE: Thanks for the very helpful and quick response!
I don't have a spark gap tester, but everything else from that troubleshooting chart was good. So as of now I'm still not able to check the high tension side of the coil. I was finally able to pull out the high tension wire from the top of the coil. Inside was melted rubber. I picked out the melted rubber and used sandpaper on both surfaces but still no start.
I'm thinking, with all that melted rubber, there must have been some abnormal heat and maybe the coil is shot. Ill just get a new coil for $40-$45 and hope for the best.
I'll post back with the results.
Thanks again,
Joe
 
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