Help with water leak on 1999 MerCruiser Bravo 3

[BillWilliams]

We have a 1999 Formula 260ss with a 310 HP MerCruiser Bravo 3.

Serial numbers:
Transom assembly: OL529806
Outdrive: OL440964
Engine: OL342220

I have a leak that appears to be around the cavity where the trim hydraulic lines attach at the bottom of the transom assembly.

If anyone has ever been down in the engine room of one of these boats knows it's a tight fit and you just can't see much of bottom of the transom assembly.

This past weekend I replace the MerCathode Electrode that mounts on the bottom of the transom assembly in the hopes that was the culprit. It wasn't.

We trail this boat and every time we put it in, it takes about a minute before we start seeing water leaking in. It's not a fast leak and when we're on plane, I'm pretty sure no water leaks in which makes sense because the entire transom assembly is out of the water.

My next plan is get down in the engine compartment with one of those snake scope cameras to hopefully try to determine where the water is coming from.

I'm afraid it's either the assembly itself or where the exhaust mates with the assembly which means I'll have to pull the engine out of the boat.

Any other ideas would be greatly appreciated.

 

[tpenfield]

Yes, Formulas seem to have tight engine compartments. I think you are on the right track using an inspection camera to get a better view of the leak.

Often, the engine has to come out, based on what is found.

 

[dubs283]

possible culprits:

-trim hose block gasket/mercathode wire seal
-exhaust y-pipe mating surface/o-ring at gimbal housing
-u joint bellows
-shift bellows
-steering shaft seal
-gimbal housing seal

 

[BillWilliams]

Thanks for the suggestions.

I put a brand new u joint bellows in place last year since I had to replace the swivel shaft that rusted and tore up the seals. Not to say I might have messed something up putting it together. I didn't do anything with the shift bellows since it had been recently replaced by the previous owner (just bought the boat last July).

I really don't want to pull that darned engine.

 

[Bt Doctur]

Its usually a corroded hole in the bottom of the Y pipe