engine dies, but why

[mrgnstrn]

Hopefully someone here will say, "oh yeah, that happened to me, and the way to fix it is ....."
i have a brand new 2-stroke Mercury 9.9 hp outboard, with remote controls (no tiller)

i attempted to run my brand new engine on saturday. started on the first crank (well, maybe second, forgot to prime the first) and purred just fine.
so after idling for a few minutes, i decided to see if it went into gear alright.
closed the hatch (but not the wooden panel) and backed out. got 30 yards from the dock and the engine just died (can't remember if it was sudden or a steady decline)
of course tried to start it again, cranked and cranked and nothing.
anyway, after miraculously floating right back to the slip and tieing up, opened the hatch, tried to crank - nothing.
took the upper cowl off - nothing.
finally after like an hour, many primings and futile attempts to crank, then for no particular reason, it finally kicked over.

see, i first thought that it was the engine choking on the exhaust fumes in the lazerette, but once the hatch was open (and even the top cowl) i would think that exhaust fumes would dissipate and she would fire up again.

and then i thought "well, maybe it flooded" but it makes no sense that it would flood once running. but it does fit the scenario after the engine died. but again, how did it flood while running.

anyone with an idea?

hopefully i will figure this all out by saturday (first sea-trials under sail)
thanks to all,

[Bill]

The time something like that happened to me was when I had failed to freshwater flush the engine after each use and the water pump was a solid block of salt :mad: The engine would run until it was hot enough to freeze up. Let it cool, it would start and for a short time, etc. My problem was that the tide was carrying me into the shore :eek: My luck held, however, and the tide began turning before we reached shore.

From my experience, it may be that you have a water pump problem. Maybe there is a factory plug or something that should have been removed. When the engine runs, is there water exiting from someplace under/near the head? If not, the waterpump isn't. :confused:

[Jim Wiles]

mrgnstrn,
I have had a number of 9.9 Mercs and:
1. I generally have to keep the panel out and the hatch cracked on a small prop for air.
2. You could have bad new plugs
3. bad gas or bad mix
4. Could be crud in the tank even if new
5. The interlock in the remote control might not be indexing in the correct detent to run. These can be a bear, I had problems and it took a while to sort it out. This is the same detent ring int the remote control that prevents you from starting it in gear.
6. Might be a bad carb or mis-adjusted.
7. The first thing that I do with a new tank or hose is to pick my spot and cut the hose in two and install an inline fuel filter.
8. Possibly a bad ignition switch
9. One last one that I also have had problems with is the lanyard switch that in Illinois is supposed to be clipped to the operator when the engine is in gear. Make sure the clip is properly holding the interlock switch in the run position.
Good Luck, Jim

[Jim Wiles]

Have you had any luck yet in finding the problem? Just wondering about you and hoping that if it didn't run well for you that she slid right back into the correct slip again!
Jim

[mrgnstrn]

well, two sides to this coin:
1. i have had good luck in that it hasn't died in the same manner since the last time
2. i have had no luck in re-creating the problem

i have run it for extended periods, both at idle not in gear, in gear at idle and in gear at 1/4 throttle with all three hatch configs:

top hatch wide open and smaller removable port out
top closed, small hatch open/out
all closed.

the only time it even faltered was when i switched gas tanks, and some air was in the line from the tank. a single squeeze on the bulb and a re-start was all that was required. but it started right away.

no idea what happened before.

but for sure, i am keeping the hatches open, for good luck.

[Theis]

For whatever it is worth, the symptons of the exhaust getting in the engine intake are not obvious. Opening the forward cover does not help - it possibly makes matters worse.

The exhaust from the pressure relief ports flows/gets sucked right up the back of the engine and into the engine cover.

I have had several xperiences with the engine failing, and they generally catastrophic. Running beautifully, stopping, and then not being able to restart - even with starting fluid.

Changing plugs is the immediate solution. No don't try cleaning them - t hat doesn't seem to work.

As for whether you smell exhaust, I generally do in weak concentrations, but because the exhaust laps right up the back of the engine cover, a heavy smell of exhaust may not be necessary.

Incidentally, I ported the pressure relief ports through the transom this year and a) it seems to be working really well. The engine is much quieter with the cover closed, and there is no, none, nada smell of exhaust. Let's hope it stays that way. b) It surprised me how much exhaust comes out of the 1/2" hole in the transom. A lot of smoke comes out of those little holes in the bottom of the engine head.

Don't know if exhaust is your problem, butr it well could be. Keep the lazarette cover open.