Powerhead removal advice, ’79 OMC 9.9?

[fleetwin]

quote johnyrude200:

Maybe I’m stating the obvious, but did you remove the 3 screws on the TOP side of the pan (one aft, one on each port and SB sides)? If you didn’t remove these 3 screws, that thing isn’t going to go anywhere.

There’s the 6 lower powerhead screws, then the 3 topside ones, then the shift lever, detach the fuel pump. I use a pry bar at the back side of the motor, near the rear SB side, because it’s located away from the bottom side of the powerhead where if you accidentally ‘mar’ the metal casting, it *shouldn’t* affect water/exhaust going into the wrong placed.

Everywhere else looks pretty iffy in terms of really applying a lot of force. I don’t screw around when these are stuck, either. I get a good ‘grab’ with the tip of a pry bar, and give it a good whack with a 4 lb. mallet. I haven’t had one stay stuck yet, and if the bottom side of the powerhead has any distortion, I use gasket sealant to make up the difference (but that doesn’t generally happen, at least not enough where a new exhaust housing gasket…which you’ll probably need anywhere…can’t fix).

Thanks for adding this clarification, those lower pan mount screws must be removed as well!

[theodore]

My 15 is a 1986. It has cooling system problems that are not fixed by servicing the pump. It’s had a hard life in salt water, so I suspect it has grommet problems. I haven’t investigated to see what kind of "updated grommet design" would be used in mine.

I think I once saw a picture of a grommet "failure" where the walls of the grommet had caved in due to a salt buildup between it and the casting it was inserted in. Maybe try to "glue" the walls of the grommet to the casting, so the salt can’t wick its way in between the two?

[Mumbles]

Here’s a collapsed grommet compared to its new replacement. it wouldn’t matter how many impellers get installed as the motor is still going to overheat with this restriction in the cooling water circuit.

Coating everything with Triple Guard grease may help to slow down any future corrosion.

[fleetwin]

quote Theodore:

My 15 is a 1986. It has cooling system problems that are not fixed by servicing the pump. It’s had a hard life in salt water, so I suspect it has grommet problems. I haven’t investigated to see what kind of “updated grommet design” would be used in mine.

I think I once saw a picture of a grommet “failure” where the walls of the grommet had caved in due to a salt buildup between it and the casting it was inserted in. Maybe try to “glue” the walls of the grommet to the casting, so the salt can’t wick its way in between the two?

OK, accidentally clicked on the "report this post" instead of the "quote" icon, sorry.
In any event, your 1986 15hp has two water tubes and two grommets. The normal long water tube bringing water up from the water pump, and the shorter water exit tube that leads water away from the open exhaust megaphone. Chances are pretty darn good these grommets are crushed if this is a salt water engine, even though the tubes/grommets are the "improved design", unless someone has already done the grommet work. I think you will notice that the new grommets are just a little higher than the water tubes, cutting about 1/8" off the top of each grommet should solve this problem.
Don’t forget to check the upper mounts while the powerhead is off, the open megaphone engines like yours are more prone to upper mount failure.

[johnyrude200]

Forgot to mention in terms of prying these off the exhaust/pan – I will use a thinly feathered chisel to get the powerhead started first. I aim the flat side of the chisel at the powerhead (to protect it more) and the tapered side toward the exhaust housing. Once you get it started, generally the thing can be shook back and forth to free it up, or a light application of force with a pry in the spot I mentioned before works.

I usually here a ‘crunch/crack’ of the gasket separating/breaking apart into several pieces, or just plain peeling back off either the powerhead or the exhaust housing.

Removing the inner exhaust tube is usually a crap shoot. Those screws break off quite a bit…which of course leads to drilling/retapping if more than 1 goes.

[Alan]

I very much appreciate all the info!
I got scared when the first thing I did was break off the tiller handle, (bolt failure from salt), just trying to straighten it out, (w/ penetrant, and rocking, and patience). I knew it hadn’t been done in about 8 years.
But, the last person who worked on it used anti-seize, and it all came apart nicely after that. Grateful I am!
Dan Gano has the parts headed my way, and even sent me a scan of the parts manual. Great guy.
Many thanks, and happy motoring!
Alan

[Author]

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