Infrequent rough running engine

[J.A. Veil]

I have a 2001 Yamaha 200-hp HPDI engine on my Parker. It has been nearly flawless in the six seasons I have run it. There is one odd feature it has that I am posting here to see if any other Yamaha owners have experienced the same thing.

At some point during the first year I had the boat, I shut the engine down to do a drift. When I restarted the engine, it idled very rough, and when I put it in gear it ran very poorly. Since this was the first time I experienced the problem, I got worried that I was having a serious engine problem. I immediately shut off the engine, let it sit for a minute or so, then restarted. It now ran perfectly. The same problem occurred intermittently, maybe once per trip. At some point I realized that the problem only occurred if I had not shifted to dead center neutral before turning off the engine. Even now, after six years, I occasionally experience the same problem. I quickly shift to neutral, turn off the engine, then restart. Voila! -- the problem is solved.

At this point, I treat this situation as an infrequent nuisance that does not require any mechanical repair. However, I am curious about why the engine behaves this way. I also ask if any of the other Parker brotherhood have experienced the same thing.

I look forward to replies from the Parker brain trust.

 

[Outta Here]

Just a guess, by not shifting to neutral first, is it possible you confused the computerized FI and it flooded a cylinder or two?

I had a similar problem w/my 23SE/200HPDI. A couple of hrs slow trolling (that's bumping throttle in and out of gear) would foul some plugs. A minute or so of moderate throttle in neutral would clear things up. As you, not enough of a problem to want others "turning wrenches" on my motor.