New member, water flow pilot hole problem

[KiwiPom]

The service manual has very little info about the water jacket and how it works. The lower area of the water jacket and the part I'm referring to is not mentioned at all.
Here's a pic of another outboard showing the area I'm talking about:



Bear in mind it does look somewhat different on mine but this should suffice.
The square-ish hole near the top is the exhaust tube coming down the leg. The grey area around the hole and between the hole and the outer surface of the leg is the grommet. On this pic it looks like its a metal casting, or even just part of the outer casing, but on mine it is definitely made out of very hard rubbery material, somehow pushed in between the exhaust tube and the outer casing. It's not in the exhaust, but surrounds it, and makes the bottom of the water jacket. It has a hole in it, approximately 6-7mm wide, to allow water to escape. The problem on mine is that water is also escaping from the 4 outer corners, where the rubber seems to have shrunk or perished. I suspect this is what is causing the low water pressure in the head.

[Solarman]

dt55, mid 90s, pee hole problems

To start with, still not sure the grommet?
That motor in the pic looks familiar, but can't put my finger on it?
Yes if motor is back together, give it a run and let us know the outcome.
Good luck. Next time take a pic of your motor, top and bottom, if able.

[KiwiPom]

Quick update:
Been a bit too busy to get the boat in the water over the last week, but have managed to get a schematic from my new friendly Suzuki mechanic. Here is the "grommet". It's part #16 in the image (#17 is the long shaft version) . It's listed as "Seal, exhaust tube housing".



I'm hoping to get some time out on the water in the next four or five days so will report back then. In the meantime I have ordered the part and will install it once the sea trial is done. I'm really hoping this is the culprit!

[KiwiPom]

Well, that turned out to be a bit of a disappointment.. Trials out on the water ended up almost exactly the same as before the work. A steady stream, reducing to a trickle, then finally ceasing altogether. Again.
I'm now hoping that the rubber exhaust jacket grommet is the culprit. At least the motor ran well during the 2 hour run, with no signs of overheating so that's something to be thankful for at least.
If that doesn't fix it I'm guessing I'll have to attempt a top end teardown to investigate further. Might have to leave that as a winter project...

[Solarman]

dt55, mid 90's, pee hole weak/ stops

Ok, then I think that exhaust grommet, if as badly burned up as mentioned, would be a good possibility. On my motors, my exhaust did interfere with my water pumps when the RPMs increased, both my pumps stopped pumping. So this grommet on yours may be allowing some exhaust to interfere somewhat the same? You would be the best judge on that call. Look where the grommet is, and see if exhaust can slip by into where the water pump picks up the water? If the grommet could be leaking enough to back pressure the chamber where water enters, then it can slow/ interfere with water pick up. While you have the lower section off, also look down the exhaust chamber for any debris/ pieces of grommet that might block exhaust as well. Exhaust pressures are much higher than most expect, and can effect how motors run.

Good luck, but keep us posted.