7.4 Mercruiser issues

[jth21usa]

I recently purchased a 1996 Crownline 250 Aft cabin this is my first cruiser. I think I?m having some performance issues:

1. Max RPM is about 4200 (7.4 Merc)
2. Has trouble staying on plane below 3400 rpm
3. Cruises at 3600 rpm about 25 mph
4. Seems to be burning a ton of fuel

Is this how this boat is supposed to operate? Could it be propped wrong or is there some underlying engine issue?

Justin Hafner

 

[jtruth]

Re: 7.4 Mercruiser issues

I have a 1996 wellcraft 33 coastal with twin Merc 454 s efi. Yep they are gas hogs. WOT at 4250 RPM they such about 60 gal per hour. Merc says they should turn between 4000-4400 at WOT. I normally cruise at 3000-3200 rpm at 26-30 gal per hour....Hey, there ain't no way to push 16000lbs through the water cheap. Good strong engines if you take care of them but they do like fuel.