Mariah Diablo
 

I took my, new to me, 1992 Diablo 18ft out for the first time yesterday and she ran great. I have a mercruiser 4.3 190 hp alpha 1 drive, 14.5x19 aluminum prop. I used the gps on my phone and clocked in at 38-39 mph consistently. Just curious, from someone with the same or similar set up ,is that a average or below average speed? Never did look at rpms at WOT, to busy looking at gps, jet skis and other boats. Should I be expecting more?

Re: Mariah Diablo
 

My 180 with the 4.3 consistently hits in the upper 40's at WOT using a GPS so your high 30's is a bit low. WOT rpms should reach 4800 but your engine could be a little bit tired, prop may not be in optimum condition etc etc.

Re: Mariah Diablo
 

Thanks for the reply. I know there are many variables to take into consideration. With 750 hours on motor, prop is beat up a bit, I’ll do some work and try to stretch another 5-7 mph out of her somewhere.