I am looking for a Sailfish 1990 vintage. I am wondering what the difference in fuel burn and cruise speeds between a single I/O and twin 150's outboard might be. Any comments appreciated.
yb
yb
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IO VS OB
- Thread starter Yellow Boy
- Start date
Oceanbean
GreatGrady Captain
I have a 1993 Explorer with a 5.7L VP DP. The Explorer is slightly narrower and shorter than the Sailfish of that year. As such you will see small blocks (350's) in the Explorer's and Big Blocks (454's or twin small blocks) in the Sailfish. At 3000 rpm, I burn 10-12 gph (depending on load and seas) at 26 mph. There are members on this site with I/O's Sailfish - that will most likely reply as well.
OceanBean
93 Explorer VP DP
OceanBean
93 Explorer VP DP
Amigo
Well-Known Member
I have a 1988 Sailfish 25 ft. hardtop with a Mercruiser 454 - 7.4 Liter. It is rated at 330 HP. I have a FloScan on it for accurate fuel readings.
Here is a typical cruise speed for me - 22 / 24 MPH at 3200 RPM using 12 GPH. I usually run with 50 - 60 gallons of gas on board, three downriggers, rod holders, lots of salmon fishing equipment, etc.. I also usually run with the plastic curtains in place.
I troll with a 9.9 Merc 4 stroke.
Here is a typical cruise speed for me - 22 / 24 MPH at 3200 RPM using 12 GPH. I usually run with 50 - 60 gallons of gas on board, three downriggers, rod holders, lots of salmon fishing equipment, etc.. I also usually run with the plastic curtains in place.
I troll with a 9.9 Merc 4 stroke.
SmokyMtnGrady
Well-Known Member
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Typically, outboard's power to weight ratio of an inboard is better and given today's lighter 4 stroke outboards, I would think you would fare better with outboards. My f150 on my previous Grady was a fuel sipper compared to the 2 stroke 150. In terms of maintenance ease of accessing the prop when in the water and generally getting the lower higher or completely out of the water, outboard would be the way to go. The other way to look at it is Grady is not building boats with IOs any longer. My opinions are based on never owning a boat with an IO.
JUMPNJACK
Well-Known Member
I/O!
Yellow Boy, You can dig up some of the previous discussions that most of us I/O guys have been involved in recently. Some good reading and information in them. My '87 Sailfish runs the small block Mercruiser 350 MPI Horizon 300 hp. My performance is similar to Amigo's. I do about the same speed at 3200-3400 rpm. I rarely ever run harder than 3600 rpm which gives me around 25-27 mph. 4000 gets us up to 30mph or a little better. My fuel burn for a typical Gulf of Mexico offshore trip 12-14 hours is usually 65 to 70 gallons. The most I have ever burned was on a 16 hour trip where I spent half of my time running at 4000 rpm trying to outrun some nasty Gulf thunderstorms. The fuel burn for this long day was 87 gallons. I figure an average burn of 6 gph on a fishing trip for planning purposes. You will find that all of us I/O guys love our setups for various reasons! Don't know what a pair of 150's will burn fuel wise but I bet they would be hard pressed to match that 6 gph that I average and the V-8 do sound sweet! I bet you get some good comments on this subject from the other I/O's! 8)
Yellow Boy, You can dig up some of the previous discussions that most of us I/O guys have been involved in recently. Some good reading and information in them. My '87 Sailfish runs the small block Mercruiser 350 MPI Horizon 300 hp. My performance is similar to Amigo's. I do about the same speed at 3200-3400 rpm. I rarely ever run harder than 3600 rpm which gives me around 25-27 mph. 4000 gets us up to 30mph or a little better. My fuel burn for a typical Gulf of Mexico offshore trip 12-14 hours is usually 65 to 70 gallons. The most I have ever burned was on a 16 hour trip where I spent half of my time running at 4000 rpm trying to outrun some nasty Gulf thunderstorms. The fuel burn for this long day was 87 gallons. I figure an average burn of 6 gph on a fishing trip for planning purposes. You will find that all of us I/O guys love our setups for various reasons! Don't know what a pair of 150's will burn fuel wise but I bet they would be hard pressed to match that 6 gph that I average and the V-8 do sound sweet! I bet you get some good comments on this subject from the other I/O's! 8)
richie rich
Well-Known Member
I have 200's on a '91. I'll never average 6 gph for a trip but we run faster, usually 25-35 and get 1-1.5 MPG (depending on sea conditions). In the bay when it's like glass it's closer to 2 but those time are few and far between.
grzch
New Member
IO vs. OB
I've got a 86 Trophy Pro with Mercruiser 454 330hp. 3200RPM 12-14 GPH 20knts with 100 gallon of fuel. If you looking at an old IO make sure you check out the engine mounts and transom. I had bad engine bed mounts and spun the coupler. With the fiberglass work and some small upgrades I spent $5000.00 repairs. I still love the boat 25' 9'6" beam, nothing like it on the water besides a new Parker 2510DV at $100K.
I've got a 86 Trophy Pro with Mercruiser 454 330hp. 3200RPM 12-14 GPH 20knts with 100 gallon of fuel. If you looking at an old IO make sure you check out the engine mounts and transom. I had bad engine bed mounts and spun the coupler. With the fiberglass work and some small upgrades I spent $5000.00 repairs. I still love the boat 25' 9'6" beam, nothing like it on the water besides a new Parker 2510DV at $100K.
JeffN
Well-Known Member
SmokyMtnGrady said:Typically, outboard's power to weight ratio of an inboard is better and given today's lighter 4 stroke outboards, I would think you would fare better with outboards. My f150 on my previous Grady was a fuel sipper compared to the 2 stroke 150. In terms of maintenance ease of accessing the prop when in the water and generally getting the lower higher or completely out of the water, outboard would be the way to go. The other way to look at it is Grady is not building boats with IOs any longer. My opinions are based on never owning a boat with an IO.
Good point but I don't think you will be able to hang four strokes on a '90 Grady transom without a major rebuild. If the transom is punky and one is looking at a rebuild anyway the OBs would be an option. Make sure you have that transom checked! I repowered my Kingfish (thats what a sailfish with I/Os was called in '83) with a 496 and am very happy with the outcome. I top out around 45 mph and cruise in the 26 to 28 knot range. I did some checking when I first got the boat back and from 20 knots to 28 knots the fuel consumption ranged from 1.8 NMPG to 2.2 NMPG. with the better fuel ecconomy coming at the higher speeds. I check my milage with every tank, total miles divided by total gallons, and I average right around 2 NMPG. Back in the day when my boat was new there was no comparison with the OB powered boats, mine was WAY more efficient. Now, as said, with the four stokes things are more even but I still enjoy my I/O. I did look at perhaps putting a bracket on with OB but it was less expensive to go with the I/O at the time. I am very satisfied with my decision. In regard to the getting the lower unit out of the water in my case the boat is in the water five months a year and my previous I/Os (twin Merc. 470s) lasted 23 years with few problems so I see that as a non issue. But that was just my experience.
kevine
Member
I have had an IO in a couple of different boats and I would not recommend them to anyone. The new outboards are the way to go. The maintenance on an IO is a nightmare depending on the access. A little bit of water on the motor and you will be replacing everything one piece at a time. I t might be easier to do your own work if you knoe car engines, but with a new out board you will be better off. The winterizing alone is a lot of work. Take the outboards if you can.
'84Offshore
Well-Known Member
I prefer the I/O myself.......
If you at all handy with car engines you will be able to work on the I/O.
I rebuilt/replaced my SBC in my Offshore basically by myself in my driveway for <$3K........would be hard to find a 300HP OB for that kind of money.
Yes, maitainance is a bit more......but I don't mind it.....and I too like the sound of a V8.....there's nothing like the sound of the SBC scream @ WOT.
If you at all handy with car engines you will be able to work on the I/O.
I rebuilt/replaced my SBC in my Offshore basically by myself in my driveway for <$3K........would be hard to find a 300HP OB for that kind of money.
Yes, maitainance is a bit more......but I don't mind it.....and I too like the sound of a V8.....there's nothing like the sound of the SBC scream @ WOT.