Hot water doesn’t work well on boat shower from block drain

[Jeffdz]

Hey all I have a 1995 Volvo/OMC 5.0L Fuel injection with an sx drive. The boat has a shower hooked up to the port side block drain for hot water and an in-line pump after the mixing valve. Problem is I don’t seem to get enough hot water to run the shower on full hot even with the inline pump running. It sprays good for a second but then seems to run out of water. I bought the boat used so Ive done some replacing of parts as well as trying to flush out the block/manifold and risers. Recently I circulated rydlyme through the motor for 4 hours to try and rid the motor of deposits and rust. But still it doesn’t seem to have enough to keep up for the shower. I’ve replaced the raw water pump and the water pump this year so I know they aren’t at play here. After this long winded story..questions are 1) is this normal to run out of water like this immediately? Or is there a blockage or something else? 2) can I install a tee and hook both block drains (port and starboard) up to the shower to try and get a steadier supply of water?

boat doesn’t run hot, manifolds usually cool to the touch. Any help is appreciated! Thanks all!

 

[QBhoy]

Hi

Its hooked up wrongly.

There is a take off fitting at the engine circ water pump (not sw pump) Also a return to block nearby too.

 

[Jeffdz]

Thanks QB. But I don’t think you know enough about the subject from your response. Plenty of people use the block drain for hot water. There is no return either. I don’t have a heater. I have a hot/cold water shower on the swim platform

 

[QBhoy]

Thanks QB. But I don’t think you know enough about the subject from your response. Plenty of people use the block drain for hot water. There is no return either. I don’t have a heater. I have a hot/cold water shower on the swim platform

Jeez. Only trying to help. Forgive me for getting the type wrong. I’m used to a hot water system that goes through a domestic tank with a coil. Fed from the engine at the pump and returns.

 

[Scott Danforth]

pull the fitting off the motor, go in there with a screw driver and break up the rocks, sand, rust flakes and crud in the bottom of your block

short of mechanical removal, there is nothing you can add to your cooling system to break up crap in the bottom of the water jacket on your block in a raw water cooled application.

if you really want hot water, plumb your source to the thermostat housing