LouC wrote:
This is one 'supposed' advantage of the Volvo & Bravo system that I don't totally understand, since the issue is not just access in certain boats, but also this design where the impeller must suck water a far greater distance than on designs that have the impeller in the drive, like the Alpha and Cobra. With the impeller in the drive, it only has to suck the water up about a foot or so, then pushes it forward. This is why it is harder to get certain boats with Volvos and Bravos to prime on the water muffs.
On the OMC Cobra, you remove a plastic cover at the rear of the upper gear housing (3 bolts) and the impeller housing is right there! Takes 15 min, you could even do it in the water if you're careful!
Yes, the location of the Cobra water pump was the greatest thing ever. 10 min job to replace impeller. I even did it while in the water (although backed up to a beach so I could stand up). However, my understanding is that it could no longer be placed there when the design switched to a cone clutch. But then the sales team calls it a "feature" to have the pump at the front of the engine
TX H210SS wrote:
I've always wondered why the water pump in these boats can't be a simple easy access in line electric pump.....hell, it works to push enough water on high performance race cars.
And why does it need to be made with weak rubber fins? It's not a suction issue or volume issue...
The electric water pumps on race cars are only the "recirculating pump" which has very little back pressure to deal with. The boats Raw Water Pump
does need to have suction to prime itself, and force a predictable volume of water from the drive, through the engine and through the manifolds. I think that would take a pretty big motor to make it electric (like a trim motor running constantly). So an engine driven rubber impeller makes sense, but why "weak rubber fins"? My old Evenrude and Yamaha outboards had very thick fins on their impellers that never broke off...after several years they would just loose flexibility. Maybe the thin fins are to limit the maximum pressure...so that with clogged (rusted) manifolds, you still wouldn't blow a hose apart and start sinking the boat.
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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings