Logo
FULL SITE MENU

RAW WATER INTAKE

J

jungpeter

New member
Does anyone have insight as to why most (all?) outdrive engine and drive packages intake the raw cooling water via the outdrive leg? Inboard-powered vessels typically intake raw cooling water via a thru-hull and sea strainer. Inquiring minds want to know!
 
overall, its a more economical solution (as far a delivered costs) to use a pump in the outdrive for most of the smaller engines...you will see the 'inboard approach' used on stern drives when the outdrive pump can't supply enough water flow...
 
I've converted all three of the Volvo drive boats I've owned to thru hull with strainer... The latest and most t rouble free solution uses an external wedge shaped strainer with a clean out port ( for the thru hull pipe itself)... Since this installation requires a shutoff inside the hull for safety reaaons, I"ve also plumbed a T fitting onto the back of the shutoff with a gate valve and hose barb so I can flush/winterize my FWC engine easily All parts are bronze or "red brass":.
 
sandkicker said:
I've converted all three of the Volvo drive boats I've owned to thru hull with strainer... The latest and most t rouble free solution uses an external wedge shaped strainer with a clean out port ( for the thru hull pipe itself)... Since this installation requires a shutoff inside the hull for safety reaaons, I"ve also plumbed a T fitting onto the back of the shutoff with a gate valve and hose barb so I can flush/winterize my FWC engine easily All parts are bronze or "red brass":.
Click to expand...
 
As a follow-up to my original posting, I queried the local Volvo Penta dealer with my question. His response was, inasmuch as the transmission (final drive reduction as well as the forward/reverse gears and clutch assembly) components of the drive system are located within the outdrive leg, the engine raw cooling water pumped through the leg is also used for transmission cooling.

In as much as the drive components within the outdrive leg run in an oil bath, which is in intimate contact with the outdrive housing, which is also in intimate contact with the raw cooling water the boat operates in, I'd be very interested in the percentage of transmission heat transferred to the cooling water pumped inboard to cool the engine, vs. dissipated directly to the sea via the outdrive housing.

Sandkicker reports he has had success with direct cooling of the engine via a separate through-hull. Anybody else? And Sandkicker-any outdrive leg failures attributable to overheat?

Regards,

Pete
 
sandkicker said:
I've converted all three of the Volvo drive boats I've owned to thru hull with strainer... The latest and most t rouble free solution uses an external wedge shaped strainer with a clean out port ( for the thru hull pipe itself)... Since this installation requires a shutoff inside the hull for safety reaaons, I"ve also plumbed a T fitting onto the back of the shutoff with a gate valve and hose barb so I can flush/winterize my FWC engine easily All parts are bronze or "red brass":.
Click to expand...
Was it easy to block off/redirect the water inlet on the leg?
 
Well although cooling water goes through the outdrive so does exhaust water (warm to hot) and if your raw water pump fails, the temp inside the outdrive will skyrocket. You can actually melt things like the grommets for the water transfer tube.
 
Back
Top