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Roel Jansen
07-20-2005, 11:22 PM
Ted,

Regarding the post on BOC about the rpm of the Mag350
what's your experience? I think I am in the 4200-4400 range with Bimini up
Mostly full or halve full gas and water. What's true about the 22 to 20 story there? Pleas your professional opinion. :D
Tedster
07-20-2005, 11:41 PM
Tain't read the post you are reffering to. Ted
Roel Jansen
07-21-2005, 01:18 AM
It, s the post about the 265 2003 engine problems.
SomeSailor
07-21-2005, 08:10 AM
Roel;

Just guessing here, but it looks as though your boat might be running a bit low in the RPM range as well?

By changing the prop on my 2355, I would drop the WOT RPM from 4800 down to 4400-4600.

It always ran higher than 4200-4400 though. You generally want a motor to top out in the upper range at WOT. And that's normally in the 4800 RPM range with most motors.

I think you'd at least want to see 4600 pretty easily.
Roel Jansen
07-22-2005, 12:58 AM
Mike,

I think the problem in this case is that a lot of boats have the same figures.

I asked the guys over here about it last year when I found out that I had lower readings at WOT and they said it was according to the book. Don S although some time I don't like the way the music sounds in his posts but that's strict personal without doubt knows what he is talking about. Not having problems with the engine combo's yet the dealer might not be aware of the fact that they are basically wrong propped. Of course I can buy other duo props and I will certainly do if necessary but if Mercruiser or and Bayliner made the mistake let's look what they want to do about it. As retirement is gone to be effective from the first of august I have some time at hands to investigate! :D
SomeSailor
07-22-2005, 08:01 AM
The worst part about them being over-propped would be the extra wear experienced on the motor. A 5.7L engine is the same in a 2355, a 265 or as a pair of them sitting in a 325. The motor has an intended RPM range at which it is designed to operate. Regardless of what outdrive it's attached to, or size of boat. Mercruiser would be the people to ask. It may simply be a compromise they chose to make because of the added weight and beam of the 265. Worth checking into though.