WOT rpms

[Galvez83]

Hello folks, after some research i have come out blank in trying to find out what is the sweet spot for rpm on my boat at WOT. The boat is a 1998 foir winns 200 horizon with a 5.8 efi. The outdrive is a volvo penta 1:60 ratio and the prop is 14.5 diameter by 19 pitch. Today i i ok it out here in Miami, Fl and the rpms where over 5800 and i was not in wot. The boat moved along but i would say at around 25 mph. No weird noises or anything like that. I had 4 people on board and half a tank of gas. Any idea of how i can get higher speed out of the boat.

 

[Bondo]

Ayuh,...... I'd think 4800 rpms for a 351,.....

The 1.60 gears sounds like to low of a gear ratio,...... I'd sooner think it oughta be 1.50, or slightly higher,......

Or,........ yer tach is off,...... way off,......
Check it against a known good shop tach,.... my timing light does such,.....

 

[Galvez83]

The tach is brand new as i replaced the whole dash as part of the rebuild. All the gauges are Faria. By no means do i say that it is not the problem but the engine does sound like its pretty accurate as i can hear the engine struggling at those rpms.

 

[Scott Danforth]

Still use a shop tach. The Faria gauges are simply cheap gauges like every other stock gauge in boats (the OEM paid about $25 for the tach)

however if you were hitting 5800, the pistons would gave joined you on deck.

If the tach was set to 6 cylinder vs V8, you would be reading 6000 RPM when the motor is only turning 4800