I have been looking at a used 31SS with 502 MPIs.
What can I expect for Cruse, Max Speed, and fuel
burn on these engines?

I had a 99 31 with 502 mpi's and it ran right around 78 mph with low fuel and trimmed out.
Not sure on gph,but it wasn't too bad......very nice boat!

Thanks,

That is good speed! I want a range of 200 miles.
As I remember Jay Ross tole me that the 502's got
1.5 MPG which for me that will be good enough.

I'm in a 31 Formula w/ 502's. I willing to bet that 78 on speedo is closer to 72-73 on GPS. (that is what mine does) The fuel burn is in the correct range, but that depends on how hard you run it.

I had a 98 31ss with 502 MPI's, labbed props and the most i ever saw was 71 on GPS. I had an Arch on my boat also, so, maybe a few more pounds.

Also, I took a run from Ft. Lauderdale to Key West, about 190 miles, I think I cruised about 50 mph and my gas burn was a gallon per mile.

my guess is you will burn all the fuel you put in it.....just buy it and start paying the arabs!

Oh I will burn the fuel. When I had my 28SS I put
about 250 hours a year on it. My main reason for the
fuel burn question is that most of my long runs are
150 miles, and I don't want to stop for fuel.

How are your engines coming?

Real slow Kaamas are on the dyno now mine are next, the 31's carry 150 gallons of fuel you can run 150 miles easy.