Helping a friend. Formula 27pc out of Florida. Transom water fitting was restricting flow so we are now picking up water from the bottom and are T’d into the seawater pump. Worked great for 2 seasons. This year it Developed a new leak at transom inside boat and I need to stop water flow from drive to transom. Wanted to know the best/safest way to plug the transom water feed at gimbal helmet from OUTSIDE the boat. Thanks...

Can you post a pic?

The inlet fitting bolts to the gimbal housing, I doubt that would be leaking, more likely a drive shaft bellow or a shift shaft bellow, or if it draws a lot of water where the gimbal housing is submerged, the steering shaft seal

the water flowing through the drive helps cool the upper unit,
if you’re set on blocking it from coming in through the transom assy.
drill and tap the l/h side of the case, Teague sells a fitting that directs
the water back on to the case to cool it

I called Teague and he acted like he has no clue. We have been round and round with this thing. I know it better than my 47 Excalibur. Yes it is leaking at the water neck inside the boat. We may or may not be able to get to it with risers/manis removed. Whoever designed these formula boats should be severely punished. So we can bypass the water at the top of the drive, but how do I safely block water at transom...no sinking allowed.

If you need to block that on the outside, you need a new transom assembly. It’s rotted and just going to keep fighting you. Merc has a block off plate for the inside. And out of the 8-10 I’ve blocked, none have had a drive failure or sign of the drive getting too hot.

With it leaking at the inlet, I would suggest remove the water inlet fitting. If its cracked or the hose needs replacing, remove the bell housing and replace the hose and fitting.

https://www.mercruiserparts.com/bam/...30967/1943/160

Never mentioned what year, but if its new enough Merc started using the quick connects and not the barbed fittings. There is a spring lock and seal which might be an issue

https://teaguecustommarine.com/em001...se-side-shower

right out of the Teague on line catalog

Here’s the inside of the cooling cavity, it contacts the lower l/h side of the case clear to the back