318's in a 70's-vintage Luhrs 32

I am considering purchasing a 70's-vintage Luhrs 32 sedan with flying bridge that has twin 318's. I am curious as to the fuel consumption of these engines at different boat speeds. Does anyone know of any tables or charts that might correlate engine RPM, boat speed and fuel consumption? Absent that, can anyone give me some idea of what kind of fuel consumption rate I can expect? As old as this old gal is, there must be somebody with experience in this. It is not a deal-breaker, just another piece of data. Thanks.

here's mine...1971 Trojan 31' twin 318's, 1:1 velvet drives, turning 14x13 3 blade props , I generally run around 2700-2900 rpm's ( out of the secondaries), gives me a cruise speed of 25- 27 mph ( gps),depending on wind & waves, flow scan says about 8gph per engine at that speed(brand new Edelbrock 1409 carbs). Bow mounted water tank that is always full, & 36in x 12in tabs ( down just enough to lift her butt slightly)..I think mines a little lighter than the Luhrs, wide open (4250 rpm) she's bumping 37 mph & I'm using the fuel gauge as a dash fan. Hope this helps

lol

Hope you consider alll the other factors of an old boat

Thanks, Pete, your comment does help. Monkey, I sure am considering all the other factors of an old boat, but thanks for the friendly reminder. What would also help would be your giving me some idea of the fuel consumption of your 31' Silverton.

Mighty good performance, Pete.

Jeff

monkey couldnt tell ya ,Aint ran it enough to tell,been down in the doghouse and aint had time to catch some air.................but

I did learn that with a couple turns on the back motor mounts,I aint rubbin n the stern tube and I can turn the prop freeely be hand

This was the problem all along with the stalling and timing nonsense,distributor was sticky

Ill relay some info when shes back in the water, of corse it will have the edlebrocks then and new intake manifold gaskets so it should be a good gauge for you,I did see that the previous owner had just put on 18x19 4 blade props

My V drives are 1.91 to 1 ratio

buddy in my boating club has a luhrs 32' and he said he gets about .7 nmpg at cruise of ~20knots? i don't remember the exact speed, but, he runs his like mine SLOW unless there is weather.

i get 1 - 1.5 nmpg going about 7-8 knots depending on the current, swell, etc, etc, etc. i have a 32' Uniflite w 360 chryslers

JB: Either boat, either way, that sounds like 12-14 GPH, which is about my estimate. Thanks to you and everyone else!

$40 per hour,hmmmm.............not bad!