MerCruiser 4.3L Ignition Issue - Help Needed

[Stingray83]

I have a 1999 Stingray with a I/O 4.3L Mercruiser. This past weekend I ran the boat for about 4 hours with no issues. After letting the engine rest for about 20 minutes, we started it up again to do some wakeboarding. The engine started running rough. It never turned off, but I could feel it sputter a couple of times. We ran the engine for another 90 minutes or so, cutting it off in between riders. On our last attempt to fire up the engine, it wouldn't turn over. No clicking or anything. Turning the key did nothing. I think this may be an ignition issue, but I am really new to boat ownership and I am completely lost. I checked the battery and it had a full charge. I changed out the ignition fuse (based on a previous issue we had last season) and that got the engine to crank a couple times before dying again. Then it went back to not making any sound when turning the key; no clicking, nothing.

Some people on the dock said it may be the ignition coil, but I don't want to start fixing things if they aren't really the issue. Thanks for any advice this post may generate.

 

[alldodge]

Re: MerCruiser 4.3L Ignition Issue - Help Needed

Your going to need volt meter.
Turn the key switch to run and see if your getting 12 volts to purple wire on the posative side of the coil. If 12 volts is present next check the Yel/Red wire going to the slave solenoid and have someone turn the key to start and see if you get 12 volts there. If 12 volts is not present check the key switch and connections leading to it. Could be a bad switch or connection. Attached wiring diagram should help.

 

[Don S]

Re: MerCruiser 4.3L Ignition Issue - Help Needed

Turning the key did nothing. I think this may be an ignition issue, but I am really new to boat ownership and I am completely lost. I checked the battery and it had a full charge. I changed out the ignition fuse (based on a previous issue we had last season) and that got the engine to crank a couple times before dying again. Then it went back to not making any sound when turning the key; no clicking, nothing.

The starter not engaging or the solenoids not clicking when turning the key eliminates the problem being the ignition. Poor battery connections, harness connections, even bad ignition switch could cause all your problems.

Did the fuse blow again? What size is it, and what color of wire was it in? Was it on the engine or under the dash?

 

[Stingray83]

Re: MerCruiser 4.3L Ignition Issue - Help Needed

The starter not engaging or the solenoids not clicking when turning the key eliminates the problem being the ignition. Poor battery connections, harness connections, even bad ignition switch could cause all your problems.

Did the fuse blow again? What size is it, and what color of wire was it in? Was it on the engine or under the dash?

I am not sure if it blew again or not, but it was one of a couple things I tried quickly troubleshooting while I was on the water. The fuse for my ignition is a red 10 and it is under the dash. Last Fall when I had the boat winterized, I had an issue with the ignition fuse and battery connections (that is sort of why I quickly tried troubleshooting those two things while on the water). While it was getting winterized the shop repaired those two things. If they did a good job it may mean that 2 of the 3 options have been ruled out for me. I am curious if there may be a bad connection to the ignition switch since when I got the boat we had some wiring issues with the trim gauge as well. Thanks for your help Don.

 

[Stingray83]

Re: MerCruiser 4.3L Ignition Issue - Help Needed

Your going to need volt meter.
Turn the key switch to run and see if your getting 12 volts to purple wire on the posative side of the coil. If 12 volts is present next check the Yel/Red wire going to the slave solenoid and have someone turn the key to start and see if you get 12 volts there. If 12 volts is not present check the key switch and connections leading to it. Could be a bad switch or connection. Attached wiring diagram should help.

View attachment 203664

Thanks for your help and the diagram- I will be picking up a voltmeter and pulling the boat home this weekend to test the coil and solenoid. I will post back here once I run these tests. I am hoping this is something simple that I can fix easily and get back on the water quickly.