Eliminating Water Heater from Mercury Engine 7.4 MPI

GAS engine, transmission and generator repair and maintenance discussion forum.
Post Reply
User avatar
Mase
Scurvy Dog
Scurvy Dog
Posts: 6
Joined: May 8th, 2016, 1:59 am
Vessel Info: 1999 370 Voyager
Location: Texas
Been thanked: 6 times

Eliminating Water Heater from Mercury Engine 7.4 MPI

Post by Mase »

Wanted to share the photos and how to eliminate the engine coolant from going through the water heater. My water heater on my Voyager 370 started leaking water and I was not comfortable having the engine coolant go ing through the water heater so I looped the connections on the engine with a piece of 5/8" silicone heater hose that is rated at 350 degrees and high pressure, yes the hose is better than you need but worth the extra 10 bucks.

Left the hoses going to the water heater in case we hook one back up and ran the new hose by the hoses and made sure the new hose was not coming into contact with anything that would rub a hole in it.

Pictures attached.

This also allows us to remove the old water heater and replace with something in the future.
You do not have the required permissions to view the files attached to this post.
Viper
CYO Supporter
CYO Supporter
Posts: 6266
Joined: July 10th, 2015, 9:58 pm
Vessel Info: 1989 Carver 3807 Aft Cabin
Location: Ontario, Canada
Has thanked: 475 times
Been thanked: 1791 times

Re: Eliminating Water Heater from Mercury Engine 7.4 MPI

Post by Viper »

:down:
User avatar
bud37
Admiral
Admiral
Posts: 5182
Joined: April 23rd, 2015, 10:22 pm
Has thanked: 604 times
Been thanked: 1312 times

Re: Eliminating Water Heater from Mercury Engine 7.4 MPI

Post by bud37 »

Mase wrote:Qr Bbpost Left the hoses going to the water heater in case we hook one back up and ran the new hose by the hoses and made sure the new hose was not coming into contact with anything that would rub a hole in it.


Looks good, If it were mine I would put new hoses to the new water heater when comes time. Once those old hoses sit dry in the bilge , rot will set in pretty quick.

Good you got the old one out, now could you reinstall a heater of the same size as the old by just reversing things?
FWIW.....The above is just my opinion.
User avatar
Midnightsun
CYO Supporter
CYO Supporter
Posts: 2984
Joined: March 27th, 2016, 2:27 pm
Vessel Info: The Midnight Sun
2007 41CMY
Volvo D6-370's
Location: Montreal, Canada
Has thanked: 272 times
Been thanked: 1193 times

Re: Eliminating Water Heater from Mercury Engine 7.4 MPI

Post by Midnightsun »

Just a tip when you replace your water heater. I found out the prices are considerably less for heaters with integrated serpentines for use with engines. I replaced my water heater with the integrated serpentine even though I do not have this hookup option on my boat. May come in useful for someone in the future.
Cheers, Hans
2007 Carver 41 CMY
Twin Volvo D6-370's
Montreal, Canada
Midnight Sun I Photos
Post Reply