Connecting water heater to engine - Maxum Boat Owners Club

Stressleave · 06-11-2008, 10:09 PM

Hi
I am trying to connect the water heater in our new boat to the engine via the heater hoses. It is the 5.0lt. MPI engine with complete closed cooling.
Could someone tell me where to connect the hoses to the engine?
This engine has a hose coming out of the front of the dome on the starboard side [which I think I should connect the output hose to] that goes down and into the top of the water pump.
Should I take this hose off and splice the heater hoses into these to ports?
Thanks for any help
Paul

seapuppy · 06-11-2008, 11:05 PM

no...get 2 new hoses and stainless steel clamps....then there is a plug on the intake manifold...pull that plug and have a fitting ready to insert using teflon tape to seal it...then attach the hose to that and the other end to the water heater...
on the top of the water pump mounted on the front of the engine...there is a plug....have a fitting that fits that plug and insert the fitting using teflon tape on the threads there too..attach your hose and clamps...then to the return of the water heater....clamp that hose there also....refill the heat exchanger with coolant and your done....may have to burp the water heater but that's easy....

SP

Stressleave · 06-11-2008, 11:32 PM

Thanks Seapuppy
The two ports you have mentioned are joined together with a short hose already.It goes from the port on the top front right side to the port in the top of the water pump.
I think I should take this hose off[and get rid of it] and attach the water heater hoses to these two ports which in the end would look like you suggested.
What do you think.
Paul

seapuppy · 06-11-2008, 11:48 PM

that'll do it...if it runs from the water pump to the intake manifold...then yeah...that's it...

SP

Stressleave · 06-11-2008, 11:50 PM

Thanks Seapuppy
I'm on it!!!!!
Paul

Brit Rider · 06-16-2008, 08:22 PM

All SeaPuppys advice is totally solid - I sell heaters (HeaterCraft) and that's exactly how we'd do it 8)

Stressleave · 06-16-2008, 09:40 PM

Thanks guy's
I have got it hooked up and it works perfect.
Paul

cbswaim · 08-26-2017, 02:15 PM

I have a 7.4L Mercruiser and understand the connections and where to find them based on the service manual. Can someone please tell me what is the size or part number for the brass threaded nipple that goes into the plug ports? This part number is listed for diesel, but don't know it will work on my engine: 805984A

Thanks in advance!