After pulling my boat for the winter I hooked up the muffs/hose and ran fresh water through the engine for a couple of minutes as I always do. This time however, I opened up the hose faucet more than usual which ran more water - at a higher pressure than usual, at the intake on the outdrive. The reason that I put more water pressure at the intake is because I was experiencing overheating when on the water, and assume that I have a bad impeller. My thought was by adding pressure to the intake, it would help the bad impeller circulate the water through the block.
I drained the oil in the outdrive in preparation for pulling the drive. I was surprised to see a gush of what appeared to be clear water come out of the bottom drain plug. It eventually turned greenish gray....not milky white. I completely drained it. I'm still at a loss as to why the water came out first (as if it was on the bottom of the outdrive). I'd think that the water would either be mixed in with the oil, or would come out last from sitting on top of the oil - water being lighter than oil.
How is water getting into my outdrive?
I've read that fishing line can wrap around the prop shaft and migrate to the seal; compromising the seal and allowing water to get in. Assuming that's not the case here, and assuming that my drain plug and vent plug gaskets are good (both are in place) how is this water getting in?
Could the pressure at the muffs be compromising a seal at the water intake, thus allowing water to get inside the outdrive?
One other thing: the trim tab has deteriorated so much that the bottom has been eaten away & the hollow casting is visible from the outside, looking up. There's no doubt that water is getting inside the trim tab casting, but since I haven't yet split the upper and lower units, I don't know if there's a way for water to seep in through the trim tab. At first I assumed that the trim tab was a completely external component, but since there's apparently a bolt securing the trim tab that goes through both castings (http://www.mercstuff.com/waterpumpinst.htm), I assume that there's some kind of water seal related to the trim tab. If water is getting inside the trim tab casting, could it be getting past the gaskets?
My boat and outdrive are at my summer house in Maine - 600 miles from my winter home. I'd like to have everything I need with me when I get up there so that I can get right to fixing this problem. I'm going to have to split the upper & lower as I'm putting in a new impeller. Aside from the new trim tab, what else should I replace as a measure of standard maintenance/replacement items when pulling/splitting an outdrive.
Thanks in advance.
I drained the oil in the outdrive in preparation for pulling the drive. I was surprised to see a gush of what appeared to be clear water come out of the bottom drain plug. It eventually turned greenish gray....not milky white. I completely drained it. I'm still at a loss as to why the water came out first (as if it was on the bottom of the outdrive). I'd think that the water would either be mixed in with the oil, or would come out last from sitting on top of the oil - water being lighter than oil.
How is water getting into my outdrive?
I've read that fishing line can wrap around the prop shaft and migrate to the seal; compromising the seal and allowing water to get in. Assuming that's not the case here, and assuming that my drain plug and vent plug gaskets are good (both are in place) how is this water getting in?
Could the pressure at the muffs be compromising a seal at the water intake, thus allowing water to get inside the outdrive?
One other thing: the trim tab has deteriorated so much that the bottom has been eaten away & the hollow casting is visible from the outside, looking up. There's no doubt that water is getting inside the trim tab casting, but since I haven't yet split the upper and lower units, I don't know if there's a way for water to seep in through the trim tab. At first I assumed that the trim tab was a completely external component, but since there's apparently a bolt securing the trim tab that goes through both castings (http://www.mercstuff.com/waterpumpinst.htm), I assume that there's some kind of water seal related to the trim tab. If water is getting inside the trim tab casting, could it be getting past the gaskets?
My boat and outdrive are at my summer house in Maine - 600 miles from my winter home. I'd like to have everything I need with me when I get up there so that I can get right to fixing this problem. I'm going to have to split the upper & lower as I'm putting in a new impeller. Aside from the new trim tab, what else should I replace as a measure of standard maintenance/replacement items when pulling/splitting an outdrive.
Thanks in advance.
) but not mixing with the oil during out-of-water operation in neutral only would explain why the water was relatively clear & hadn't mixed with the gear oil.