Gulfstream with Twin F150s

Finatic

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Looking for some feedback from any Gulfstream owners with Yamaha twin F150s. What hole are your engines mounted on? Also, what props is everyone running? Lastly, I'd like to hear what the real world performance numbers look like. What's your average fuel economy with a crew of 3 and full gear for a day offshore? Looking forward to the feedback,
 

cgmiller

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Finatic,
I have a 1990 Gulfstream with a pair of 2004 F150's (with a flowscan meter) and they are pretty sweet setup on this hull. I average about 2.3 miles per gallon. I spinning counter rotating 17P stainless props. At 3400 rpms, I run 24-25 mph burning about 5 gallons per hour per engine or about 10 gallons per hour total.

At 4000 rpms, I am running 30 mph and burning 7 gallons per hour each engine or 14 gallons per hour combined. 4500 rpms sees about 35 mph and wot just touches 40 mph..I dont recall off hand what the WOT is, but it is right in the Yamaha recommended range.

I just went out and looked at the boat (she is still in the driveway) and they are bolted at the top bolt hole, but I had the tranny replaced last spring and they remounted the engines. I looked at the back of the boat and the anticavitation plates are level with the bottom of the hull....
 

Finatic

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Chris,
Yeah that answered my question. I'm hanging a pair of F150s on the back of my 2000 Gulfstream. Looking forward to the better fuel economy.
 

gwwannabe

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I have a 93 Gulfstream with twin 140 Suzukis 4 strokes. My speed/rpm numbers are nearly identical but I don't have a way to measure fuel consumption. All I know is that I use less fuel now than I did when I had the Overnighter with a 200 hp Johnson 2 stroke. Love my Gulfstream.
Gary
 

ioffe

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Two weeks ago I became a proud owner of 2007 232 with '06 F150s. My performance #s are pretty much inline with cgmiller's, but we had full tank and 4 big dudes riding her. I couldn't get her moving faster 40.5 mph. The boat is in a fiberglass shop for some cosmetic repairs. Once it's out, i will update you with more accurate numbers.

Just for the reference, I was once on '08 232 with F350 which did 45mph with ease, and 32mph @ 2.1 mpg.
 

cgmiller

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Ioffe,

The 232 with the single 350 had 50 more horsepower and half the drag with only 1 engine in the water..the drag of the outboard makes a big difference...
 

magicalbill

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Just to add to the conversation...

My 2007 232 has twin 200's(4-strokes) I get 1.9-2.0, rarely 2.1 MPG at 3600-3800 RPM's cruising between 28-31 MPH.

This comes in handy when you want to get somewhere..
I run 4400-4500 and maintain 35-36 MPH. Mileage drops to 1.6-1.7 or so...

It'll turn just South of 50 MPH firewalled and trimmed out.