www.iFourWinns.com

I have had similar issues when using muffs, maybe not overheat in 2 to 3 minuts but the motor runs hot. I have chaulked it up to cheap muffs that dont seal for crap around the outdrive.

I have the 5.7 volvo dp, the raw water pump is on the front of the crank pulley. So if you think about it, when running on muffs the pump has to lift water 12-18 inches or so due to the muffs not sealing so it really isnt pressurized, but when you run in the lake the water level is the same level or maybe even higher than the raw water pump itself so the pump doesnt have to lift at all. Make sense?

If anybody knows of a good set of muffs that seal on the drive let me know where you get them, all the ones I have seen are similar to the ones I already have.

Jeff

03' 268 Vista "Simon Sez"

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Jeff

'14 Cruisers 380 Express "Simon Sez"
Merc 8.2 Mag MPI 380
DTS B3X, (x2) Axius Premier


(SOLD)
'08 V318
Merc 350 Mag MPI 300
DTS Seacore, B3 (x2)

I have a heavy duty set of dual inlet muffs that seal tightly, when the engine is running there is very little to no leakage around them, Tempo used to make them but I think they are out of business now, but West Marine and Overtons still carry a similar model.
Overtons Large Pro motor flusher cat #71731 $19.99
West Marine Dual Feed rectangular cups cat # 31-66133 $21.99

There are also Volvo specific models in both catalogs, but I don't know if they are for the more Swedish style Volvos or the American style SX drives, I think any of the two above will work fine.

And I think using a 3/4 in diameter hose helps to with more volume of water. I do think the point of the Volvo (or Bravo) pump being on the engine may make it more difficult to get the impeller to prime, especially if the impeller is slightly worn, or the boat is stored with the bow high and the stern low (water has to travel up hill then). When running on the muffs with an engine mounted impeller, I'd jack the bow down to help the water flow up thru the long hose from the transom to the impeller.

Mine is an OMC Cobra which has the impeller on the aft end of the upper gear housing, primes in a second or so and never a problem on the muffs. Also about the easiest to replace impeller I have ever seen.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II