I left the harbor idling good went up to cruising speed (all…

Ok, that sounds like the outdrive is locking up. I am just thinking about how that could be. Have you changed the oil in the lower end and checked it for metal shavings, and make sure the oil is clean and clear? I think I would do that right off.

Ok, my first thought was that we had caught a line on the prop. It could be that the engine was losing power and thus would not push the prop at all.

Maybe.

Or the lower end is locking up.

I am thinking about this for a moment. When you put the engine in gear did it lock up or die out? As in did the engine hit hard or did it roll to a stop? That might give us a hint as to what is happening.

Yes, that is making me think maybe the coil is failing. You did well not revving up any higher than 2K at the dock. Lol.

Ok, that shutting down is good info. Do you have two engines? So we can check the resistance of one coil to the other. That would be a good test. Or you could swap coils. This is the ignition coil I am thinking of.

It could be fuel and it could be vapor lock, but it does not sound like it. You can rev up in neutral?

And then rolls to a stop when put in gear so we can say we have lost power sometimes when the engine warms up. Yes, that could be a fuel issue.

We should be sure to change the fuel filters. That is just basic though. I am still thinking of a definitive point to see. Oh, you might have the bump shut down during gear shift. I wonder if your engine has that. That is different than the neutral lockout. There is this other switch that some engines have that when you shift to gear the spark is shut off for a half-second to de-load the shifting. The neutral switch is in the start wire so we can't start the engine in gear.

Let me look up if you have that. Mercury 190MR. BRB.

Any idea what year? I see three different shift systems. I am looking now.

Check out this drawing. The switch is #18. Do you have that on your engine? If that switch was not working correctly then that would for sure give you the shut-off in gear symptom.

That is a cutout switch. It was meant to fix an issue where the gears were hitting too hard, so when you shift the engine cuts out for a mili second during the shifting.

That would be an easy fix. That was a good call.

The wire from the switch would go back to the module. This switch was on the later engines. Let me know if that is there. We can disable it for testing. We kind of want the issue to happen again so we can test.

Yes, let me know what you find. If the switch is there then we can disable it for testing.

You bet. We are here to help. These intermittent issues are always the most tricky to sort out.

What I am thinking is maybe the cutout switch is failing and when the heat hits the switch then the switch becomes unstable. Maybe. We have to test. Another thing to try is when this happens again is to work through the complete wire loom part by part. You shut down, wiggle one section of the wire loom, and then test and check for any difference in the issue, then test another section of the loom. In this way, we might stumble onto a fault that is hard to find otherwise.

Just yesterday we had a boat in the shop that had an intermittent fault for the last few years. The tech wiggled the wires and tested, and wiggled and tested, and so on till he got a change in the fault. Then we opened all the wire loom and found a fuse someone had put into a wire and taped over. That fuse was in the housing and the wire had rotted off but would still make contact because the housing was holding the wire in place till it vibrated then it would shut off and restart. Crazy but that stuff happens. So the loom trick is pretty good if we can't find the fault otherwise.

Ah, good. That is great. Thank you for 40 years of work to keep the machines working. That is part of what makes the world function. Take care out there and we'll chat after you check the shift area.

Does it look like the engine that is running well has had the cutout switch disabled? Is that the hanging wire?

I was just thinking maybe we should disable the cutout switch?

Then test.