BACK TO DRIVE RATIO

[BUY_B]

I STOBE-TACHED THE CRANK SHAFT AND THE DRIVE SHAFT ON MY 1986 290XF WITH CRUSADER 270 HP ENGINES. THE CURRENT RATIO IS 2.1-1.
JUST LOOKING FOR INFORMATION HEAR, DOES ANYONE HAVE THE SAME BOAT AND DRIVE LINE, AND IF SO IS THIS RATIO NORMAL?
THE ENGINES WILL ONLY MAKE 3800 RPM, BUT THE PROPS HAVE NOT BEAN CHANGED FROM THE TIME IT WOULD MAKE 4800 RPM.
ANY HELP WOULD BE APPRECIATED, THANKS

[fisheadgib]

I've got a 1988 290 but I have the 265HP mercruisers with Borg Warner velvet drives. the tag on my tranny's says they are a 1.88 to 1, so your ratio sound close to OEM. They only made this boat for a few years and I suspect they did some experimenting.

[fisheadgib]

I"m repeating my other reply that disappeared. I seriously doubt anything was done to your transmissions. 1000 RPM is a sizable difference in speed.
Did you own the boat during or before the rebuild? Or are you going by information that the previous owner gave you? I believe the WOT setting range for those engines (along with mine) is 4000 to 4500RPM. 4800 is kinda pushing it, especially for engines that old. When they were rebuilt, the mechanics probably set them at the safe end of factory spec's. I run mine at 4000RPM at WOT to make them last a little longer. After putting together a bunch of data between speed, RPM, fuel burn, and weight, my prop shop determined that I need 19" props with a 17" pitch. (thats with a generator, full load of fuel and water, and tipping the scales around 15,000 lbs.) I think it would save you more in the long run to get your props retuned and making your engine last longer.