89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

Hi there.

I have a 1989 Glastron Sierra with a 130hp 3.0L Mercruiser with digital ignition. The outdrive is an Alpha One. I'm having some ignition problems I'm hoping to get some help with. I checked the Adults Only sticky and read the troubleshooting guide for points ignition which gave me some good info and things to try after work tonight, but I'm not sure if there's anything additional or different I need to check for the digital ignition.

Here's what happened:
I was out on the lake going averaging 15-20mph at 1/2 throttle, everything running strong. Let off the throttle to about 1/4 after cruising for about 15 minutes and the engine just shut off and wouldn't start again. Carb getting fuel, fuses looked good, voltage reading 12 on gauge, starter still cranks engine. After trying everything I could think of on the water, we got a tow and drove home.

What I've checked:
Fuse under helm looked good. Plugs looked good. Lanyard kill switch was pressed (wouldn't allow engine to crank if this was the problem, correct?). Pulled two plugs, connected wire and held threads against block while cranking - no spark. Popped distributor cap off, everything looks dry and clean. Traced purple and red/purple wire from alternator to coil, control unit, circuit breaker (which appears fine - button can't be pressed), choke, etc? the fusible links look a little worn, but seem to be ok.

I will go through the troubleshooting steps in the Points Ignition link in the Sticky post, but if there's anything else I should check or if there's something obvious I'm missing please let me know. If you need any more info, let me know. I can go get model numbers or photos if that helps.

Thanks.

-Matt

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

You can't troubleshoot your system like a points system, because you don't have points.

Try this instead.

View attachment DDIS.pdf

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

Don S said:

You can't troubleshoot your system like a points system, because you don't have points.

Try this instead.

View attachment 153025

Click to expand...

Yeah, that's what I figured. Thank you for this.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

OK. I went through the troubleshooting steps and there's no power from the harness going to the ignition amplifier. All the gauges work and all I replaced the 20A ignition fuse under the helm. Went through the rest of the troubleshooting steps, coil resistances were good, motion sensor resistances were good, shift interruptor continuity checked out.

Anything obvious to check as a next step? Is the kill switch (lanyard) involved in this circuit or would that prevent the starter from cranking? The tach is the only abnormally reading gauge, it reads ~800 when the key is off and in the "RUN" position. When turning ignition key, the needle bounces a bit but goes right back to ~800.

Thanks.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

Did you go through the component tests as well as the chart?

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

Yes. The first place it failed in the component tests was #1 and #2 under "Ignition Amplifier"

The coil tests all passed.

The motion sensor test and Shift switch tests passed.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

OK. I went through the troubleshooting steps and there's no power from the harness going to the ignition amplifier.

Click to expand...

Maybe I misread your earlier reply. Withe the key in the RUN position, you don't have any voltage on the purple wire at location A in the picture below, correct? If not, then check at B and C and see if you have voltage.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

That's correct. I've already checked at the electric choke, no voltage. The wire from the alternator I haven't checked. It's fully insulated so I'm not sure where to check it. There are three wire couplers which I thought were fusible links but they honestly just look like crimp connectors/couplers.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

The alternator is really the only component that purple wire touches that I haven't tested. Would any of the alternator components being faulty be a cause for no voltage and therefore no spark? I'll test that wire (B in your diagram) after work today.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

Well, I traced that wire after getting no voltage at alt to the lanyard switch, which was faulty. Jumpered it out and running great. Thanks Don S, I learned a lot about my boat through this troubleshooting.

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

I know this is some serious thread resurrection, but I have the exact same problem on the exact same engine right now and I can't figure it out. I have 10V coming out of the Amplifier on the one terminal (purple), but nothing on the other that is supposed to be within 1/2 volts. I assume that it is a bad Amplifier, but I don't know how to tell if perhaps it is low voltage coming in. On the 3-terminal plug-in for the amplifier, I have 10V on one terminal (purple) and .38 on the other (yellow). Is that normal or do I have a bad connection somewhere in the harness? Thanks!

Re: 89 Mercruiser 3.0L 130hp w/ Digital Ignition - No Spark?

starsnbars89 said:

I know this is some serious thread resurrection, but I have the exact same problem on the exact same engine right now and I can't figure it out.

Click to expand...

Then start a new thread of your own like the red warning bar and the forum rules, along with the Announcement at the top of this forum suggests.