Ugarph1982
Cadet
- Joined
- Apr 8, 2017
- Messages
- 16
I have a 1988 Mercruiser 3.7 with an Alpha One Gen One. Despite the idiosyncrasies of the engine, it's been quite reliable for me and provided a lot of fun. This post concerns a finding during my annual maintenance on the outdrive. This year, those maintenance items included gear oil change, new bellows (all 3), water hose, sea water pump, and new prop. The disassembly went fine and yielded no major issues. All rubber parts were intact, but due to be replaced.
One anecdote (before I get to the problem) ... Last winter, I found that my exhaust bellows had torn, but the others were in good shape, so I was just going to replace the exhaust. Anyone who has tried to change out an exhaust bellows without removing the bell housing hinge pins knows how big of a pain in the ass it is to get the bellows attached to the bell housing (and I have the expander tool.). Needless to say, I said "screw it" and just put an exhaust tube (used on the V8 motors) on the transom assembly that just slides over the bell housing inlet when the trim is down. That worked fine, but I didn't like how much noisier the boat was, so I knew I would switch back to a bellows this year when replacing the rest of them.
The problem .... I noticed a little bit of milkiness (water) in the oil when I drained it. The fluid was still dark blue, but had some cloudiness. After I split the cases and changed out the entire water pump assembly (including the base with the oil seals and gaskets), I went to put the halves back together. A quick look into the upper half revealed that the lower water seal (that I replaced 2 years ago) and the water pocket cover where melted and dis-formed (both on the side where the exhaust enters the drive). The damaged seal was a smoking gun for the water in the oil.
It's worth noting:
--I NEVER run the boat out of water without the water adapter and good water pressure. Even with the adapter, I only run it for a few moments and at low RPM's.
--The engine does not run hot at all ... Pegs at 160 per the thermostat.
--The impeller on the old water pump was in decent shape when I removed it (no missing rubber)
--I have, of course, ordered a new water pocket assembly and lower seal which will be easy to replace.
What I need help with ... What could be causing this? I know exhaust gases are hot, but mixed with water from the exhaust, I would not have expected this kind of damage in 2 years. Below are my theories. Please poke holes in them.
1) Water delivery issue. Perhaps the pump wasn't delivering enough water ... Hard to believe because the engine was not running hot even on the warmest of days.
2) The aforementioned exhaust tube ... Perhaps enough of the water was escaping from the tube before going into the drive, but the exhaust gases were still making their way through the drive. Ehh ... maybe.
3) Maybe the engine was running too lean and EGT's were too high ... No backfiring or performance issues though (hole shot or top end)
4) Maybe it's just par for the course for the old Alpha Ones.
Any input would be greatly appreciated. Sorry for the long-winded post!
Thanks!
One anecdote (before I get to the problem) ... Last winter, I found that my exhaust bellows had torn, but the others were in good shape, so I was just going to replace the exhaust. Anyone who has tried to change out an exhaust bellows without removing the bell housing hinge pins knows how big of a pain in the ass it is to get the bellows attached to the bell housing (and I have the expander tool.). Needless to say, I said "screw it" and just put an exhaust tube (used on the V8 motors) on the transom assembly that just slides over the bell housing inlet when the trim is down. That worked fine, but I didn't like how much noisier the boat was, so I knew I would switch back to a bellows this year when replacing the rest of them.
The problem .... I noticed a little bit of milkiness (water) in the oil when I drained it. The fluid was still dark blue, but had some cloudiness. After I split the cases and changed out the entire water pump assembly (including the base with the oil seals and gaskets), I went to put the halves back together. A quick look into the upper half revealed that the lower water seal (that I replaced 2 years ago) and the water pocket cover where melted and dis-formed (both on the side where the exhaust enters the drive). The damaged seal was a smoking gun for the water in the oil.
It's worth noting:
--I NEVER run the boat out of water without the water adapter and good water pressure. Even with the adapter, I only run it for a few moments and at low RPM's.
--The engine does not run hot at all ... Pegs at 160 per the thermostat.
--The impeller on the old water pump was in decent shape when I removed it (no missing rubber)
--I have, of course, ordered a new water pocket assembly and lower seal which will be easy to replace.
What I need help with ... What could be causing this? I know exhaust gases are hot, but mixed with water from the exhaust, I would not have expected this kind of damage in 2 years. Below are my theories. Please poke holes in them.
1) Water delivery issue. Perhaps the pump wasn't delivering enough water ... Hard to believe because the engine was not running hot even on the warmest of days.
2) The aforementioned exhaust tube ... Perhaps enough of the water was escaping from the tube before going into the drive, but the exhaust gases were still making their way through the drive. Ehh ... maybe.
3) Maybe the engine was running too lean and EGT's were too high ... No backfiring or performance issues though (hole shot or top end)
4) Maybe it's just par for the course for the old Alpha Ones.
Any input would be greatly appreciated. Sorry for the long-winded post!
Thanks!