Water Leak Question

[akcooper9]

I sprung a leak this year that I can't seem to track down on my Aplha 1 Gen 2. I've replaced the U Joint bellow and shift cable bellow along with the upper swivel shaft pin and seal (all of which was needed). I no longer have water up top or midway up etc.

This leaves me to believe the leak is 1 of 2 things. The Exhaust Y pipe oring OR trim manifold junction block gasket.

Questions:

1) Can you buy just the gasket for the trim manifold junction block? How often do these leak?

2) Whats the best way to test if the Exhaust Y oring is leaking?

 

[Bondo]

Questions:

1) Can you buy just the gasket for the trim manifold junction block? How often do these leak?

2) Whats the best way to test if the Exhaust Y oring is leaking?

Ayuh,....... #1, Yes, at any Merc dealer, or possibly right here at iboats,.....

#2, Back it into the water, 'n LOOK,..... a digital camera can put yer eyes, where yer head won't fit,....

 

[akcooper9]

Thanks Bondo. Is there a good resource on finding these specific part numbers?

I think Ill replace the trim manifold gasket and then lake test again because I know the exhaust Y will require a motor pull

Also, am I missing anything with my line of thinking?

 

[Bondo]

Ayuh,.... If the hull is 15 years old, or older, transom rot is a possibility,.....

 

[alldodge]

Would be best to at supply a year of the drive to verify the part number.
The seal should be 41802 which is item 12

http://www.mercruiserparts.com/bam/subassembly/30860/1942/70

The Y pipe seal normally never leaks. Might also be leaking by a soft transom.

 

[akcooper9]

Would be best to at supply a year of the drive to verify the part number.
The seal should be 41802 which is item 12

http://www.mercruiserparts.com/bam/s.../30860/1942/70

The Y pipe seal normally never leaks. Might also be leaking by a soft transom.

Great website, thank you.

Boat is a 2003. All my investigation thus far shows the transom is sound. Tried the screw driver poke, alignment was spot on when I had the drive off etc.

I've tried putting a hose on the exhaust opening at the transom and it does not leak but I would imagine that is different then sitting in the water?

Boat does have 600 hours so maybe the Y bolts are loose?

 

[Bondo]

so maybe the Y bolts are loose?

Ayuh,..... Possible, but I've never found a loose bolt on a y-pipe,.....

 

[harringtondav]

Also possible, but unlikely, wet leak points are the trim sender's wire grommet, impeller hose transom fitting and inside seal. If you have a lube monitor, the transom hose fitting could be leaking. Also rare. Your trim hoses connect to a anti corrosion fitting under the bottom of the gimbal hsg. This has a seal. If this is loose, or the seal is bad water can enter under the Y pipe.

My bud removed his bilge drain plug flange screws and the flange dropped into his flange. If you remove this and the plastic/nylon bushing you will get a tiny peak at the transom's condition at ground zero where most rot starts. Goop the bushing with silicone or marine sealant before you reinstall.

If you have small hands, have a small digital camera, and are agile you might be able to get a peak at the transom cut out edge above the bottom of the transom plate around the Y pipe.

The transom plate hardware torques up at 25 ft lb. max. If you can sneak a torque wrench on a lower fastener and find it loose, it could be a sign of a soft transom.

 

[akcooper9]

Also possible, but unlikely, wet leak points are the trim sender's wire grommet, impeller hose transom fitting and inside seal. If you have a lube monitor, the transom hose fitting could be leaking. Also rare. Your trim hoses connect to a anti corrosion fitting under the bottom of the gimbal hsg. This has a seal. If this is loose, or the seal is bad water can enter under the Y pipe.

My bud removed his bilge drain plug flange screws and the flange dropped into his flange. If you remove this and the plastic/nylon bushing you will get a tiny peak at the transom's condition at ground zero where most rot starts. Goop the bushing with silicone or marine sealant before you reinstall.

If you have small hands, have a small digital camera, and are agile you might be able to get a peak at the transom cut out edge above the bottom of the transom plate around the Y pipe.

The transom plate hardware torques up at 25 ft lb. max. If you can sneak a torque wrench on a lower fastener and find it loose, it could be a sign of a soft transom.

I spent an hour or so out in the shop with the boat. Dropped the anoid and manifold. Can see where the manifold to transom assembly 'could have been leaking'. Cleaned everything up and will order the needed gaskets and water test.

Also pulled some screws on the inside and poked all around the transom where its cut out down low and everything was dry/hard. At this point Im going to take it one step at time.

Will report back.

 

[harringtondav]

Also pulled some screws on the inside and poked all around the transom where its cut out down low and everything was dry/hard.

Will report back.

This is a good sign. Have you tried running your boat on flush muffs after pulling and replacing the bilge plug to empty the bilge? If the bilge makes water you can eliminate transom problems, and start looking from the transom water inlet forward. Lots of easy loose plugs and hose clamps to find....hopefully. This may also smoke out a very loose Y pipe joint or other exhaust water leaks. But tightening that Y pipe joint with the engine in place....let's hope not.

 

[akcooper9]

This is a good sign. Have you tried running your boat on flush muffs after pulling and replacing the bilge plug to empty the bilge? If the bilge makes water you can eliminate transom problems, and start looking from the transom water inlet forward. Lots of easy loose plugs and hose clamps to find....hopefully. This may also smoke out a very loose Y pipe joint or other exhaust water leaks. But tightening that Y pipe joint with the engine in place....let's hope not.

Im not sure I follow your post.

I get no water in the boat on muffs. The water that is leaking is is lake temp water not warm/hot.

 

[harringtondav]

Im not sure I follow your post.

I get no water in the boat on muffs. The water that is leaking is is lake temp water not warm/hot.

OK. just trying to eliminate large potential areas. Keep working on the wet side of your transom. If your transom is sound and the transom plate fasteners are snug, there are a very few leak points to investigate. But don't overlook the simple. Like I mentioned earlier, that bilge bung plug can weep. My plug's threads became rounded from bilge sand. A new brass pipe plug helped. My sealant gooping above dried up both my and my bud's bilges.

 

[akcooper9]

OK. just trying to eliminate large potential areas. Keep working on the wet side of your transom. If your transom is sound and the transom plate fasteners are snug, there are a very few leak points to investigate.

Will do. Im determined to figure this out! I appreciate the help.

 

[scoflaw]

Get the boat on a trailer and jack the tongue up as high as possible. fill your boat with water just below the starter. Observe

 

[harringtondav]

Get the boat on a trailer and jack the tongue up as high as possible. fill your boat with water just below the starter. Observe

Darned over thinking. Simple normally leads to the fix. scoflaw . Solid advice.

 

[alldodge]

fill your boat with water just below the starter.

Do not agree, puts the wrong pressure on the trailer and the transom. Can also cause other issues/leakes, but like we all have opinions. mine just differs

 

[scoflaw]

Darned over thinking. Simple normally leads to the fix. scoflaw . Solid advice.

Ha Ha.. yup this works

 

[JASinIL2006]

I would never, ever fill my boat with water to find a leak... it's asking for trouble and unless you submerge the engine, you aren't testing a good many places that could leak.

 

[scoflaw]

I would never, ever fill my boat with water to find a leak... it's asking for trouble and unless you submerge the engine, you aren't testing a good many places that could leak.

On a trailer at a good angle you can submerge the lower half of your transom assembly, where he thinks his leak is at. Been there done that several times..fear not.