BONDO10

Question for the motor guys. Looking at some possible new to me boats.Would really like a 700 Merc or Illmore set up.But see a few good deal on 850 and 1075 packages. When top end or re-fresh time is due,can anything be done to get 200-300 hours out of them. Even if it meant de-tuning to 700-750 hp??
Thanks,Jeff

mikebrls

im sure they can after one of the premier engine builder's get a hold of them.
as far as bringing down the HP. once you have that power and run the boat I doubt that you would want to loose so much power and speed .
IM sure they can keep the power and still make them live a lot longer then merc recommended rebuild's.
plus if you keep the rpm's down on the higher power motor's and run it like a 700 or so I would think they would live longer .

mike

mikebrls

example , let say you buy a 850 merc boat that doe's 110mph and cruise's at 90 mph , well if you now cruise the boat at 60 mph and don't go past 90 I think they will live a lot longer , but we all no how hard that would be

1 MAIDEN AMERICA

I'll swap you my 700HP 575's for the 850's. See how easy that was.

mcprodesign

Just don't use the top end and keep the hp!!! 1075's need top end matinence I have heard but not so much the 850's. What kind a boat are you looking at?

Young Performance

The problem with them is the solid roller camshaft. That's why they have the short top end rebuild intervals. When the top end needs to be done, switch them over to a hydraulic roller and they will live for 200-300 hours. The bottom end can certainly handle it. You can keep the power and have the longer interval. Us, along with others, are getting 300+ hours from 1000+ hp with hydraulic rollers. There is no reason that the 850 can't do the same.

Let me know if I can help.
Eddie

glassdave

iTrader: (1)

Just curious because I'm not an engine guy but why don't they have hydraulic rollers OEM if there better? Thanks

Young Performance

Honestly, I couldn't tell you for sure. I never understood why Merc used a dry sumped, solid roller 557 ci with a quad rotor to make 850 hp. It makes absolutely no sense to me. Hell, I don't see why they put a solid in the 1075.

The only reason that makes any sense to me is so they can get the money on the rebuilds do to the short rebuild interval. I hate to think that anyone would deliberately do that, but I can't think of any other reason.
Eddie

BONDO10

Thanks for the response's guys.Don't really have any hard interest in any one particular boat,but I do like the 2005 Outerlimits 42 Legacy in the classifieds. Blue/Lime Green.I understand running the 850/1075 at a lower rpm for longevity,just didn't want to pull them apart every year.
Eddie (YPM) great info on the hyd vs.solid set up.
What would be an estimated cost on changing over 850's to hydraulic at top end re-fresh time?
Thanks,Jeff

smiklos@sunprint

iTrader: (1)

Not to Hi-jack this thread but......Eddie have you put closed cooling on a 850? There are some good buys out there on 850 and 1075 boats. For what I am looking for I would need closed cooling and hydraulic lifters.
Thanks
Steve