Boat leaking through raw water intake pipe while sitting
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I have a '92 bow rider (I/O) with a 4.3 Mercruiser Alpha 1 Gen 2 and I've got a leak coming in when the boat is sitting in the water - coming in through the raw water intake pipe that goes through the transom. When running the boat in neutral on trailer sitting in the water, the leak is almost non-existent because the raw water cooling system is running the water through and out the exhausts (no clogs). Obviously, I have a leak somewhere and I'm hoping it's just a seal on the outdrive but wondering if anybody has any thoughts?
I did try to reverse engineer by connecting a garden hose to the hose in the engine bay that connects to the raw water intake pipe (while the boat was out of water) and all I noticed was water coming out through the intake grates and a hole under the exhaust bellows.
Happy to share any additional information that might be helpful and/or can post some pictures. Thanks in advance!
I did try to reverse engineer by connecting a garden hose to the hose in the engine bay that connects to the raw water intake pipe (while the boat was out of water) and all I noticed was water coming out through the intake grates and a hole under the exhaust bellows.
Happy to share any additional information that might be helpful and/or can post some pictures. Thanks in advance!
#2

Can you get the boat/trailer on a long boat ramp with consistent angle... enough so you could let water in, up to safe level, then pull her out of the water at the same angle, put the plug back in and see where the water exits? It very well could be hull/transom related rather than engine/drive. KISS. Bring a friend, good flashlight and thank you six pack for your buddy.
Last edited by CTXOK; 01-23-2021 at 11:51 AM.
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CTXOK Thanks for the quick reply and good idea - I'll probably bug one of my buddies to do this soon just to be safe. I did a visual check when the water was backed into the water on the trailer (not running) and could see what appears to be a multiple gallons per minute flow in through that raw water intake pipe - no other leaks that I could see coming into the engine compartment. Are there seals on a sterndrive that would be causing that condition? My first thought was that maybe there is some kind of seal behind those intake grates that maybe failed but I'm relatively new to diagnosing mechanical issues on boats. Any information is appreciated!
#5

Was the boat winterized by you or a shop? Perhaps someone disconnected your raw water pipe without noting it on their RO. You just said in your latest post you think you saw where the leak is coming from when the boat is not started, now grab your bud and try this again.
#7
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Are you sure it isn't coming from the steering arm and trickling down on the raw water pipe? Can't count how many transom assemblies I've replaced in the last 5 years because of a worn steering shaft.
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Yep, drain plug is in
No winterizing on this boat (live in South Texas), good thought though on maybe the hose being disconnected. I can see that the hose is on at the transom side but maybe it’s popped off at the impeller side.
Great point, honestly I’m not sure. It does appear (when looking at my outdrive) that my raw water pipe is above the u joint bellow so could the steering shaft be leaking down into the raw water line if it’s below the pipe? Also if the steering shaft was leaking, would the water only come through the raw water pipe or would it come in through the driveshaft / gimbal bearing? Apologies if I have any of the terminology off but thanks again for all of the help!
#9
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How about some pics.
#10
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coming in through the raw water intake pipe
Might want to check the raw water intake tube for corrosion
Might want to check the raw water intake tube for corrosion
Last edited by Thalasso; 01-23-2021 at 06:29 PM.
#11
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Yep, drain plug is in
No winterizing on this boat (live in South Texas), good thought though on maybe the hose being disconnected. I can see that the hose is on at the transom side but maybe it’s popped off at the impeller side.
Great point, honestly I’m not sure. It does appear (when looking at my outdrive) that my raw water pipe is above the u joint bellow so could the steering shaft be leaking down into the raw water line if it’s below the pipe? Also if the steering shaft was leaking, would the water only come through the raw water pipe or would it come in through the driveshaft / gimbal bearing? Apologies if I have any of the terminology off but thanks again for all of the help!
No winterizing on this boat (live in South Texas), good thought though on maybe the hose being disconnected. I can see that the hose is on at the transom side but maybe it’s popped off at the impeller side.
Great point, honestly I’m not sure. It does appear (when looking at my outdrive) that my raw water pipe is above the u joint bellow so could the steering shaft be leaking down into the raw water line if it’s below the pipe? Also if the steering shaft was leaking, would the water only come through the raw water pipe or would it come in through the driveshaft / gimbal bearing? Apologies if I have any of the terminology off but thanks again for all of the help!
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Thanks to everyone for the advice! I ended up pulling the drive yesterday and pulled the bell housing since I'm going to just do a bellows job while it's apart.
Attaching a few pics below but given the corrosion, I'm fairly confident that the leak was coming in where the bell housing and drive meet for the raw water flow - that little o-ring seal is probably my issue. If anything else is noticeable from these pics, please let me know. Thanks!




Attaching a few pics below but given the corrosion, I'm fairly confident that the leak was coming in where the bell housing and drive meet for the raw water flow - that little o-ring seal is probably my issue. If anything else is noticeable from these pics, please let me know. Thanks!




#13
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I don't think I'm following you. You see a leak when in the water, but don't see exactly where it's coming from.
If you run the boat on a hose, and it does not leak, then it is not the raw water system leaking into your boat. The pump is in the drive, and regardless of hose, or lake, the water would still get into the bilge if the leak was on that system. The o-ring you are looking at would leak pressurized water out, not into the boat.
U-joins and corrosion actually look pretty good.
I think the steering shaft is where your leak is, as other's have posted.
If you run the boat on a hose, and it does not leak, then it is not the raw water system leaking into your boat. The pump is in the drive, and regardless of hose, or lake, the water would still get into the bilge if the leak was on that system. The o-ring you are looking at would leak pressurized water out, not into the boat.
U-joins and corrosion actually look pretty good.
I think the steering shaft is where your leak is, as other's have posted.
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I don't think I'm following you. You see a leak when in the water, but don't see exactly where it's coming from.
If you run the boat on a hose, and it does not leak, then it is not the raw water system leaking into your boat. The pump is in the drive, and regardless of hose, or lake, the water would still get into the bilge if the leak was on that system. The o-ring you are looking at would leak pressurized water out, not into the boat.
U-joins and corrosion actually look pretty good.
I think the steering shaft is where your leak is, as other's have posted.
If you run the boat on a hose, and it does not leak, then it is not the raw water system leaking into your boat. The pump is in the drive, and regardless of hose, or lake, the water would still get into the bilge if the leak was on that system. The o-ring you are looking at would leak pressurized water out, not into the boat.
U-joins and corrosion actually look pretty good.
I think the steering shaft is where your leak is, as other's have posted.
Just to be clear, the leak that I see inside the engine compartment is coming in through the raw water intake pipe so that's why I said that I can see it when sitting in the water - I just couldn't tell where it was originating but it sounds like this steering pin can leak down into the same spot to cause my problem.

#15
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Is the boat new to you?
Yes you can do the repair without pulling the engine by cutting the top of the drive. But if you have the ability to hoist it, and a place to work on it , I wouldn't shy away from an engine pull if you're mechanically inclined. If you have it in your budget new transom assemblies are the way to go. Pulling the engine gives you an opportunity to clean everything up, access your starter, bilge pump,etc to make it all good for another 10 years.
Add bellows cost, steering pin costs, gimbal bearing costs, etc up. Then look at the price of new transom assembly, and realize it comes with all new trim cylinders, trim lines, bellows, seals, gimbal bearing, steering actuator ,water pump line, shift cable, etc. All factory assembled. I've re-built them, and changed them and I'd be very hard pressed to ever rebuild them again if they are that old. It's a wash if your gimbal ring is bad, then I'd 100% say go new transom assembly.
Yes you can do the repair without pulling the engine by cutting the top of the drive. But if you have the ability to hoist it, and a place to work on it , I wouldn't shy away from an engine pull if you're mechanically inclined. If you have it in your budget new transom assemblies are the way to go. Pulling the engine gives you an opportunity to clean everything up, access your starter, bilge pump,etc to make it all good for another 10 years.
Add bellows cost, steering pin costs, gimbal bearing costs, etc up. Then look at the price of new transom assembly, and realize it comes with all new trim cylinders, trim lines, bellows, seals, gimbal bearing, steering actuator ,water pump line, shift cable, etc. All factory assembled. I've re-built them, and changed them and I'd be very hard pressed to ever rebuild them again if they are that old. It's a wash if your gimbal ring is bad, then I'd 100% say go new transom assembly.
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Is the boat new to you?
Yes you can do the repair without pulling the engine by cutting the top of the drive. But if you have the ability to hoist it, and a place to work on it , I wouldn't shy away from an engine pull if you're mechanically inclined. If you have it in your budget new transom assemblies are the way to go. Pulling the engine gives you an opportunity to clean everything up, access your starter, bilge pump,etc to make it all good for another 10 years.
Add bellows cost, steering pin costs, gimbal bearing costs, etc up. Then look at the price of new transom assembly, and realize it comes with all new trim cylinders, trim lines, bellows, seals, gimbal bearing, steering actuator ,water pump line, shift cable, etc. All factory assembled. I've re-built them, and changed them and I'd be very hard pressed to ever rebuild them again if they are that old. It's a wash if your gimbal ring is bad, then I'd 100% say go new transom assembly.
Yes you can do the repair without pulling the engine by cutting the top of the drive. But if you have the ability to hoist it, and a place to work on it , I wouldn't shy away from an engine pull if you're mechanically inclined. If you have it in your budget new transom assemblies are the way to go. Pulling the engine gives you an opportunity to clean everything up, access your starter, bilge pump,etc to make it all good for another 10 years.
Add bellows cost, steering pin costs, gimbal bearing costs, etc up. Then look at the price of new transom assembly, and realize it comes with all new trim cylinders, trim lines, bellows, seals, gimbal bearing, steering actuator ,water pump line, shift cable, etc. All factory assembled. I've re-built them, and changed them and I'd be very hard pressed to ever rebuild them again if they are that old. It's a wash if your gimbal ring is bad, then I'd 100% say go new transom assembly.
One other question that I wanted to raise is that it appears as though my gear lube line coming off the transom must have fallen off at some point. If you look at my last picture, the gear lube hole is there but I actually didn't remove anything so that had my curious right from the beginning. Wondering if this is common and what that would do in terms of damage since no oil is getting to the drive? I'm still confident that my leak is from the steering pin but looks like I need to replace that gear lube hose as well. TIA!
#17
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The early alpha's didn't have reservoirs. If you look at the helmet, there isn't a plastic check valve in there sticking out. Only Gen2 alpha has the gear oil reservoir. Take a look at the drive its self and you won't see a place for it.
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Edit: moving to a separate thread since this is a different issue thank my original leak problem
---------------------------------
Update, my kit from JR Marine came in and I was able to successfully remove the swivel shaft pin and then entire gimbal ring - ordered a new SS pin so will be all set to just put everything back together and hopefully correct my leak problem.
Issue that I’ve run into is that my left gimbal ring ear must have had a crack in it that I didn’t notice before I was working the ring to get the pin to drop (after I did notice that it looks like it was repaired before) - now my ear has completely fallen off and is just hanging from the trim rod...I assume a new gimbal ring is in my future and repair is out of the question to reconnect that ear?
Any suggestions on where to find a reasonably priced replacement gimbal ring for an alpha one gen 2? I’m open to used / refurbished. Thinking boat scrap yard might be the best option. TIA!
---------------------------------
Update, my kit from JR Marine came in and I was able to successfully remove the swivel shaft pin and then entire gimbal ring - ordered a new SS pin so will be all set to just put everything back together and hopefully correct my leak problem.
Issue that I’ve run into is that my left gimbal ring ear must have had a crack in it that I didn’t notice before I was working the ring to get the pin to drop (after I did notice that it looks like it was repaired before) - now my ear has completely fallen off and is just hanging from the trim rod...I assume a new gimbal ring is in my future and repair is out of the question to reconnect that ear?
Any suggestions on where to find a reasonably priced replacement gimbal ring for an alpha one gen 2? I’m open to used / refurbished. Thinking boat scrap yard might be the best option. TIA!
Last edited by sal3107; 02-01-2021 at 11:00 AM. Reason: Moving to a different thread given different issue
#20
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Look used, we have a few lying around I'll send you a PM.
Again, the math really adds up to new transom assembly as you're seeing. I know you already have the tools and parts, but for anyone else reading this, a new transom assembly generally turns out to be not much more cash for a whole lot more value.
Again, the math really adds up to new transom assembly as you're seeing. I know you already have the tools and parts, but for anyone else reading this, a new transom assembly generally turns out to be not much more cash for a whole lot more value.