The 496HO with closed cooling and the Bravo X1 drive with the gear case low water pickup system is spec'd up to 50 psi water pressure. You should have no problems of excess water pressure with a transum water pick up. It is the folks that use direct sea water cooling that really need a dump valve to protect the engine cooling system from excess water pressure....ie above about 30 psi max. The real area to be carefull with is to get enough cooling water esprcially with a stepped hull aerating the water.

Correct... closed cooled motors do not circulate the raw water thru the motor. On a 496, the only water from the lake/ocean is going thru the various coolers, then thru the heat exchanger, and out the exhaust system. Typical full throttle water pressure is between 40 and 50 psi. This is fine. You do not want to install a pressure regulator in this type of system. Max water flow is what you are after.

Rage is also correct in that proper pickup location is crucial as to not get aireated water due to steps in the hull.

Chris

I second Chris' input. No regulator. With the seawater circuit, the higher the volume the more it cools and won't logically rupture the tube used. The most important is placing the pickup to not get air in the circuit. That really reduces the system's cooling efficiency.

Russ

If you decide to go with the external pickups, the way you keep the water going through the drives is to drill and tap the upper case of the drive and put a pipe fitting in. You should also re tap and put a pipe plug in the helmet part of the gimbal as well as plug the transom water inlet. Here is a photo of mine. I would not use anodized aluminum fittings in salt water as mine in freshwater corrode very fast.

get out the hole saw G!!!!

Here is another plumbing option if you have an extension box or if you wanted to dump the water back thru the transom to the top of the drive.

Chris, can you show an example of where you tap in the upper?

I just wanted to point out and KNOW THIS IS AN OLD POST. Merc warranty the repairs and they did it per MERC book times and procedures per how the OEM wanted it done. To get the warranty done especially for the boat owner sake and his no expense out of pocket ---- one has to follow the OEM instructions plus ship back all the old parts to MERC that were covered under warranty.

With that said the dealer here did exactly what was needed as it sounds like. . I just hate when boaters think that they got ripped off by true marine dealers in the industry. Yes some do get ripped off and many do not. And for the record book times are not in the dealer favor either . Just saying and wanted to bring this up form a 11 year post.

Says Merc warranty covered repairs just bringing this up that's all

I had that set up on my Pantera. I would still run a hose from the inner transom water port to a hull dump. There could be too much water pressure at speed with just the drive shower.