1988 Mercruiser 3 liter 4 cylinder with an alfa one leg cuts out

I have a 1988 Mercruiser 3 liter 4 cylinder with an alfa one leg, I took it out yesterday it had not be run for 18 months, it started fine with a new battery. I went out for about 20 minutes cruising at about 25 mph, and first I noticed the tacho had stopped working but all other gauges working fine, within a couple of minutes with no warning the engine just cut out. I tried to restart the boat but nothing, it just turned over but no attempt to fire. I checked the coil lead to the ground of the engine but no spark. After approx 1 hour of trying different things I had given up.

So I called a towing company, 2 minutes later my 5 year old son kept on turning the engine and…it fired and then started to run! I managed to get back to within 500 meters of where I launched the boat and it cut out again and will not re start. At home yesterday I changed the coil out but still no spark.

Any direction please.

Re: 1988 Mercruiser 3 liter 4 cylinder with an alfa one leg cuts out

read this:

How To: Troubleshoot a Points Ignition System
http://forums.iboats.com/mercruiser...oubleshoot-points-ignition-system-335407.html

Re: 1988 Mercruiser 3 liter 4 cylinder with an alfa one leg cuts out

You must have a "Hot" wire to the coil when the switch is on. The Tach also gets its signal from the coil. Since the tach quit first, and repeated fiddling with the switch made it start once, I would assume that 12volt supply is not making the trip from switch to coil. If it were mine, I would run a temporary wire from battery to + side of the coil and try it. If that didn't work, I would jump across the solenoid, and see if that would start it, with the temp wire still on the coil. I would not try any of this if you aren't sure of what you are doing.

Re: 1988 Mercruiser 3 liter 4 cylinder with an alfa one leg cuts out

Thunderchicken68 said:

You must have a "Hot" wire to the coil when the switch is on. The Tach also gets its signal from the coil. Since the tach quit first, and repeated fiddling with the switch made it start once, I would assume that 12volt supply is not making the trip from switch to coil. If it were mine, I would run a temporary wire from battery to + side of the coil and try it. If that didn't work, I would jump across the solenoid, and see if that would start it, with the temp wire still on the coil. I would not try any of this if you aren't sure of what you are doing.

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