Need Advice - 75 hp Mercury/Force/Tracker - Kind of long

[Hyco Bass]

1998 75 hp Force by Mercury for Tracker S/N OE313718.

I replaced the water pump impeller last month. Old one was still working, but the pee stream was getting weaker so I figured after 20 years might be time for a bit of preventative maintenance. I have owned the boat for 16 years and besides lower unit oil changes, one coil pack and one fuel pump the motor has been without need all this time.

While I had the lower unit dropped in there I found that the previous owner (who only put two tanks of gas though the boat since new) likely changed the pump put once before as there was evidence of a blob of clear silicone at the base of the pump. I highly doubt this silicone was native to the factory. I removed the remainder of the silicone and sealed it up.. So, two impellers in 20 years. The silicone detail may just be a red herring to the issue I am writing about.

I achieved the desired result (nice, steady pee stream).I had the boat out twice and the engine runs like new. Idles smoothly and can run as long as I want at the red line despite 20 years of, what I would consider, hard service. I know, that last statement is the kiss of death for a 2 stroke.

So what is the issue? After running the motor all day and putting it on the trailer I now see "goop" running down from under the lower cowl. This goop is oily almost greasy (beige colored) and smells and feels like partially burnt fuel mixed with water. It is the same sort of goop that I have seen drip out the upper exhaust vent (I think that is what it is called, see picture) in small amounts over the years. The picture shows the goop leaking from the cowl, not the exhaust vent. The first time this happened I attributed it to just water getting in under the cowl there and washing out some old fuel/oil so I cleaned everything in the area (it was not all that dirty except for the goop at the inside bottom base of the cowl port side). Nothing on the starboard side of the engine. This was after 6 hours of mostly idling (was working on my new sidescan). Never noticed any goop there prior to my impeller change

Fast forward to today. Same scenario as far as running the motor and the goop returned. Perhaps not as much (an ounce, total, everywhere). Now that I had a spotless surface I think I can see where the goop originates. It appears to be coming from near the base of the cylinder block exhaust cover. There was a small mound of the goop there, a hamster sized pile of goop as it were.

I have a feeling the improved water pressure has reviled a weak spot in my plumbing.

So.......I need advice. Do I a) Ignore the goop and just clean it up each trip b) "Fix" it....but I don't know what is broke. I suspect one of the gaskets on the exhaust cover has parted, but it is on the bottom so I cannot see it.

Is there water supposed to be behind the exhaust plate?

How do you drop the lower cowl? I almost seems like you have to disassemble half the engine to drop the cowl to get to all the bolts on the exhaust plate.

Sorry for the long post.

And to all the keyboard warriors hating Force products.........This one, at least, has stood the test of time. I got my monies worth out of it........ But did I pay cash (ha-ha)?

[JOE54]

very likely base gasket or ex plate leak , oh boy you get to pull power head , may can try retorque all bolt with engine warm ,prob gona have to come apart good luck hope this helped ya (JOE warrior hater)

[SilverFox579]

The clear high temp silicone was most likely the exhaust dam and was from the factory. I don't know your engine to say, but my Optimax had the clear high temp silicone exhaust dam from the factory (I am original owner) and I replace it when servicing the water pump annually. Joe or Don will have to confirm whether the silicone dam should be restored in your engine, on the Optimax it's purpose is to keep exhaust gasses from getting to and potentially overheating the water pump.

That said, I don't think it in any way is a contributor to your brown goo issue.

[JOE54]

^^^^^^ yup

[Hyco Bass]

Thanks for the information. I appreciate the prompt replies. From what I hear you say is that to get to fix the exhaust cover I will need to pull the head.

I guess it is time to comb the internet for that "how-to". Does not look like fun.

[JOE54]

powerhead bolts, shift linkage, trim wires,anything else that would keep powerhead from commin straight up, aint that bad, watch bolts on side plate may break off in block

[Hyco Bass]

Will have to rate this a 7 of 10 wrench job. Bought the service manual off ebay, for a 1996. Could not find a 98, but did not look like many differences. Most difficult part? Manual had one more bolt called out to hold the block down that existed. Stumped me for a while. One of the better manuals I have ever used otherwise. Cleaning the old gaskets off......scraper, gasket solvent.......not even budged it. Ended up at HF and they had a set of scotchbrite pad like gasket remover kit to put on an air tool, so that and a new air tool did the job. Took two kits. Next was finding the under block gasket. Not easy. Took awhile. Found the right one in a kit of gaskets, ebay. Motor is back together. Tested on muffs, waiting for the lake.

Thanks for the input!

[JOE54]