1994/5 M5B - troubleshooting/questions

This is a new to me motor that came packaged with a sailboat I recently purchased. First time owning a two-stroke - as I had a diesel inboard before this, and a 4 stroke on a smaller boat in the past...

On this motor toward the bottom of the Drive Shaft Housing there is a rubber grommet/plug on the side - about the size of maybe a quarter.

When operating I noticed water was spraying around the grommit - never saw that before - in the bucket I noticed some brownish discoloration in the water foam. When I then went to change the lower unit oil - guess what - choco milk was flowing out...damn..

The motor had been last winterized about 8-10 years ago and was stored indoors. I took the motor to the local Tohatsu dealer to be prepped from it's long sleep of 8-10 years - they changes the impeller and fuel line - they said it started and ran fine. They also told me the water spray from around the grommet was normal...i have my doubts.

EDIT: The motor starts fairly easily, it idles - but if I bring down the throttle to bear min it sounds like it might stall - but it doesn't. Sounds fine once I bring up the RPM's.

So my question is this normal?

If it is normal, my assumption is that either the water pump seal or gasket is bad, or O-ring seal around the propeller shaft housing, or maybe even one of the screws for draining/filling the lower unit has a bad rubber washer. The screw washers seemed OK, but when I refilled with fresh oil, I noticed that some lower unit oil was seeping - might just be the fact that I didn't tighten it enough perhaps...

SECOND question - this engine seems to rev extremely high when I give it some throttle in Neutral - a bit scary - i can't open the throttle completely as I feel like the powerhead is going to explode....is this normal for a 2 stroke?
Thanks!

Congratulations; you now have an almost-indestructible motor. They run and run, but never run especially well. Think "stone hammer technology" of Fred Flintstone.

The grommet on the stbd side of the exhaust housing is how you access the shift rod coupler. If it is dried out or shrunk, you could get leakage of combined exhaust and cooling water there. If the water pipe is not correctly seated in the top of the wp, you will not be pumping to the powerhead, but will be filling the exhaust housing, and that leak would then be a lot worse, plus you would run too hot. There are drains that will shoot water out down there when running. That's normal.

I hope the dealer did a complete wp kit instead of just the impeller -- pumps better, and lasts longer, for minimal additional cost.

Yes, those old 2-strokers run dirty, and your test tank will soon become cruddy. There is a fair amount of unburned fuel/oil mix that comes down the exhaust housing. It can even drip out of the prop hub.

Either have a seal kit installed in the LU or do it yourself, to get rid of the chocolate milk gear oil. Be sure to do the cam rod bushing o-rings, which takes finesse, and is often overlooked. You may then need to change the LU lube a few times to get all the contamination out. The fill and drain plugs use fiber washers, which are reliable, and can sometimes be re-used, but new ones are cheap. A pair comes in the LU seal kit.

That motor needs to idle up around 900 to be steady. Slower, and you will get some extra spitting and stumbling, like any low-mass 2-stroke.

NEVER over-rev in neutral; you can break the connecting rod or otherwise damage the motor. Stay near idle in N. Yes, with low mass, it revs easily.

Paul, thanks for the reply. The dealer did not do a complete WP, just an impeller...so looks like I'll order the LU kit - I have the Tohatsu manual, so will use that as a guide. Re the cam-rod bushings hopefully I don't need a seal puller or the like...

No seal puller required (though it can make it somewhat easier/faster).

The seals can be driven out with a blunt screwdriver or drift punch, and the new ones can go in using an appropriate socket as a ram, and pressing in with your shop vise.
Pay attention to the direction the seals go... they will work backwards, but won't work as well.

To remove the inner o-ring from the cam rod bushing, I like to use a stainless dental pick. The new o-ring will require some finesse to get it in the groove; sometimes a drift punch or rod will help you manipulate it into the groove.

Thanks for the input Paul.