Water penetration in Alpha 1 sterndrive

[Alphawater]

In fall 2022, I had a full service done on my Alpha 1 sterndrive including replacing the gimbal bearing, new bellows and a new water pump assembly in the lower unit by local marine mechanic. Due to health reasons, i did not use the boat until summer of 2023. There is now a slow water leak coming in thru the sterndrive just above the bilge plug - it is at its highest volume when I first launch the boat with the sterndrive in the upper position - slows down when unit lowered. Took back to same marine mechanic to check and he said all looked good. Leak continued after relaunch in same pattern - marine mechanic then suggested it could be the transom plate that needs to be resealed - this response doesn't make sense to me with my limited knowledge - there was no leak prior to his repair work and the stern drive assembly is securely fixed to the transom - I even used marine grade sealant around the sterndrive on the hull transom and retested - still leaks when launched. In using garden hose in driveway, there is no water leakage when pouring water on the top, bottom and sides of the outside transom assembly - but I can get some leakage by spraying water into the middle portion of the outside transom assembly. Input/advice appreciated about what may be taking place. Thanks.

 

[Scott Danforth]

could be a leaking bellows, could be a soft transom that is leaking.

 

[kenny nunez]

Just like SD posted, take a close look at the shift cable bellows with the drive raised. There is probably a small crack. If the shift cable was not replaced then the bellows is the original one.

 

[Alphawater]

Thanks for the replies. As recommended, I will inspect the shift cable bellows with the drive raised. Think I need to focus on current thoughts/status. I have owned the boat for 5 years now and used the same marine mechanic during this time. During these years, the boat has rarely been in the water (never overnight) but I have kept up the maintenance and it has always been stored under cover. Was rarely used and well maintained by prior owner. Also, the boat had no leaks prior to the gimbal bearing and bellows replacements that I paid for in fall 2022. I don't see any way that it could be a soft transom and am strongly questioning the transom plate reseal suggestion by the marine mechanic with the boat use and maintenance condition. I'm trying to investigate if there is some other way water was getting in with my limited knowledge. After reading your responses and doing more research, I'm at the conclusion that if the marine mechanic had done the gimbal bearing and bellows replacement correctly, there shouldn't be a leaking problem. Thanks again for the input.

 

[bbook83]

Thanks for the replies. As recommended, I will inspect the shift cable bellows with the drive raised. Think I need to focus on current thoughts/status. I have owned the boat for 5 years now and used the same marine mechanic during this time. During these years, the boat has rarely been in the water (never overnight) but I have kept up the maintenance and it has always been stored under cover. Was rarely used and well maintained by prior owner. Also, the boat had no leaks prior to the gimbal bearing and bellows replacements that I paid for in fall 2022. I don't see any way that it could be a soft transom and am strongly questioning the transom plate reseal suggestion by the marine mechanic with the boat use and maintenance condition. I'm trying to investigate if there is some other way water was getting in with my limited knowledge. After reading your responses and doing more research, I'm at the conclusion that if the marine mechanic had done the gimbal bearing and bellows replacement correctly, there shouldn't be a leaking problem. Thanks again for the input.

 

[bbook83]

Check the clamp on the U-Joint bellows for tightness at the transom assembly. You can access it from the outside with the drive up. You should be able to see if the bellows has slipped down from where it should be.

 

[Scott Danforth]

transom seals just dont go bad

 

[Scott06]

Thanks for the replies. As recommended, I will inspect the shift cable bellows with the drive raised. Think I need to focus on current thoughts/status. I have owned the boat for 5 years now and used the same marine mechanic during this time. During these years, the boat has rarely been in the water (never overnight) but I have kept up the maintenance and it has always been stored under cover. Was rarely used and well maintained by prior owner. Also, the boat had no leaks prior to the gimbal bearing and bellows replacements that I paid for in fall 2022. I don't see any way that it could be a soft transom and am strongly questioning the transom plate reseal suggestion by the marine mechanic with the boat use and maintenance condition. I'm trying to investigate if there is some other way water was getting in with my limited knowledge. After reading your responses and doing more research, I'm at the conclusion that if the marine mechanic had done the gimbal bearing and bellows replacement correctly, there shouldn't be a leaking problem. Thanks again for the input.

Not sure the age of the boat but anything is possible. Even a boat kept under cover inside etc gets water in it. My previous boat had two soft spots in the floor where you came back on board from the swim ladder and between the consoles- where the floor got wet when in use. This was a boat that was religiously covered and spent winters inside.

I would inspect the bellows on the trailer, possible something was done wrong or a bellow has split. Put the boat in the water and look for water coming in. The three places that come to mind are

transom seal- as mentioned these start leaking when transom gets soft unless there is corrosion.
bellows - driveshaft and shift. Exhaust bellows can be torn and no water should leak in. You may have to move the drive up and down side to side to get it to leak if the bellows is an issue.
exhaust down pipe where it meets the gimbal housing, there is a seal and the pipe can corrode thus weeping water in.

This is best done with a scope camera so you can get down behind motor.

 

[Cali_Boat_Guy]

transom seals just dont gobad

transom seals just dont go bad

Does it always mean the transom is soft or can a blow to the ourdrive cause the transom seal to fail. Anything else that can cause it?

 

[Scott06]

Does it always mean the transom is soft or can a blow to the ourdrive cause the transom seal to fail. Anything else that can cause it?

impact can certainly mess with transom assembly seal, but usually there is a hole in the outdrive... OP needs to do some investigation to see where it is leaking in before cause can be determined

 

[kenny nunez]

Back the boat down the ramp with it strapped to the trailer as much as possible. That should show where any leaks are.

 

[Lou C]

When you took it to the mechanic did he actually pull the drive to check the D/S bellows?

 

[ROY WILLIAMS]

Thanks for the replies. As recommended, I will inspect the shift cable bellows with the drive raised. Think I need to focus on current thoughts/status. I have owned the boat for 5 years now and used the same marine mechanic during this time. During these years, the boat has rarely been in the water (never overnight) but I have kept up the maintenance and it has always been stored under cover. Was rarely used and well maintained by prior owner. Also, the boat had no leaks prior to the gimbal bearing and bellows replacements that I paid for in fall 2022. I don't see any way that it could be a soft transom and am strongly questioning the transom plate reseal suggestion by the marine mechanic with the boat use and maintenance condition. I'm trying to investigate if there is some other way water was getting in with my limited knowledge. After reading your responses and doing more research, I'm at the conclusion that if the marine mechanic had done the gimbal bearing and bellows replacement correctly, there shouldn't be a leaking problem. Thanks again for the input.

take it off in the fall of the outdrive ,,, then inspect it... bellows ,,,,,the shaft/shifter grease it ,, moly grease ...
every year in the fall ....the outdrive gear oil is inspected it ..

 

[Alphawater]

Thanks for the multiple areas to investigate - am checking as time allows. I checked the bellows visually and could not find any cracks - new in appearance. Using garden hose in the driveway, I couldn't get any water to penetrate inside the hull where I observed the leak previously. The slow leak occurs in a few seconds after the back end of the boat being fully submerged in the water (motor not started yet). Again the leak is a bit faster when the outdrive is in the upward most position - appears directly above the bilge plug assembly (but not through this assembly).

One current question regarding transom seal - am I correct in understanding that the transom seal protects against water penetration from the outside of the stern assembly drive where it meets the transom (not internally through the bell housing, etc.)?

 

[04fxdwgi25]

I am not there to see it, BUT, if leak changes with drive in different trim positions, I would be seriously looking at the bellows. That's the only thing that changes with trim.

Maybe he didn't seat the bellows correctly, didn't "time it" in the proper position, use the proper adhesive, or worse, maybe didn't tighten a clamp.

 

[todhunter]

One current question regarding transom seal - am I correct in understanding that the transom seal protects against water penetration from the outside of the stern assembly drive where it meets the transom (not internally through the bell housing, etc.)?

Correct. The transom seal keeps water from going between the sterndrive assembly and the transom - it's a foam rubber seal. The bellows is what keeps water from getting through the bell housing. There are two bellows - a small one for the shift cable and a large one for the driveshaft. Make sure you're checking both of them, because either could cause water to enter the bilge if they are compromised.