Fuel consumption from a 225 - 250 hp 4 stroke outboard

[Brian Dinsley]

I am planning to buy a RIB later this year, probably during the winter months. I have priced up a new 6.3 metre outfit with a Honda BF150. With electronics and trailer, I'm looking at around the 30 grand mark. However, I've spotted a few nice used RIB in the 6.8 metre+ range, usually fitted with 225 to 250 HP 4 stroke outboards. Buying one of these would initially be a substantial saving over a new 6.3 metre outfit and would come with other equipment, such as anchors etc, which makes me wonder whether I wouldn't be better off buying a bigger (and better???) used boat. Problem is, I need to know just how bad is the fuel consumption going to be?

I'll be using the boat for family cruising, fishing and diving with mates. Could anyone advise whether a day out with a 6.8m & 250 hp motor is likely to be a hugely costly affair, and what sort of fuel consumption I could realistically expect to see.

Thanks

Brian

[Milo72]

I run a suzuki 250 on a ribcraft 7.5m when estimating fuel I worked on 8-9g/h at full ahead and 4-5 g/h as an average just gently running about [cruising/skiing etc] I now have a FLOSCAN meter fitted which is excellent, very accurate. at full ahead it uses 44 L/H, but at 45kts you can cover a lot of ground!

[codprawn]

Originally Posted by Milo72

I run a suzuki 250 on a ribcraft 7.5m when estimating fuel I worked on 8-9g/h at full ahead and 4-5 g/h as an average just gently running about [cruising/skiing etc] I now have a FLOSCAN meter fitted which is excellent, very accurate. at full ahead it uses 44 L/H, but at 45kts you can cover a lot of ground!

How accurate is that? Someone on here has just reported 85l/h with a Suzuki 300hp - it can't be THAT much different for 250 can it???

If so you could have 2x 250 for the same consumption as a single 300 - doesn't make sense to me!!!

[Brian Dinsley]

Originally Posted by Milo72

I run a suzuki 250 on a ribcraft 7.5m when estimating fuel I worked on 8-9g/h at full ahead and 4-5 g/h as an average just gently running about [cruising/skiing etc] I now have a FLOSCAN meter fitted which is excellent, very accurate. at full ahead it uses 44 L/H, but at 45kts you can cover a lot of ground!

Hi Milo72

I've seen your boat and it does look nice. I've checked other threads, and there seems that different users get a broad range of fuel consumption on a boat/ engine combo of this size. As Codprawn quotes, it seems that some engines typically burn 85 ish lites per hour

I'd like a boat of that size, but this sort of consumption could mean that a days boating could cost 300 quid!!! I would be running at cruising speed most of the time, so hopefully consumption wouldn't be up in the dizzy 80's, but even at 50 litres per hour, a day out could be more than 200 quid. Last RIB I owned was a 5.1 metre Tornado with 60 HP Yamaha 2 stroker. A different animal.... I think.

Anyone else have typical fuel consumption figures for a 6.8 M+ rib with 225 to 250 hp 4 stroke??

Thanks everyone...

[Milo72]

It's not that bad... don't fear the 250...! If I'm out all day [5-6hrs] and working the throttle hard, I reckon on using no more than 130lts.
taking into consideration that it's not 5-6hrs constantly flat out of course, but most of the time she's running at above 4krpm
last summer I was out for 4hrs skiing with a family, the kids wanted to blast about, 6 skied, just a family day on the water. 45lts.

I honestly don't think you'll be disappointed.

[behavin]

i have the df250 (now fixed..!! see electrics) and i get 25-30 litres/hour on the flowscan at 28 knots which i think is pretty good.

when you crack the laughing stick though the needle reads 75-80 litre/hour which gives 48 knots on a 6.8 ribcraft.

I had loads of ribbing about getting such a large engine with ref to fuel consumption but this one is better than my old delta with twin 65's.

[simmons0]

Milo I can't help but think your figures are optimistic.
You can't spend 4 hours water skiing on 45 litres of fuel. I'd expect ours to use more than that, skiing drinks it.

I've been on a lot of boats with 200hp+ outboards and they all seem to use more like 70l/h WOT and about 30l/h at a 30knt cruise.
H

[codprawn]

Seeing these figures makes me realise my "old" 2 stroke efi isn't so bad after all. I use about 85lh flat out and about 25-30 crusing. The fuel injection and twin spark must be helping quite a bit.

[Ferdi]

Originally Posted by Milo72

I run a suzuki 250 on a ribcraft 7.5m when estimating fuel I worked on 8-9g/h at full ahead and 4-5 g/h as an average just gently running about [cruising/skiing etc] I now have a FLOSCAN meter fitted which is excellent, very accurate. at full ahead it uses 44 L/H, but at 45kts you can cover a lot of ground!

let me doubt a little about the 44 l/h with a 250 HP engine.
my Johnson 140 ( = Suzuki 140) 4-Stroke uses 45 l/h at WOT and high revs.

[Mollers]

Originally Posted by behavin

i have the df250 (now fixed..!! see electrics) and i get 25-30 litres/hour on the flowscan at 28 knots which i think is pretty good.

when you crack the laughing stick though the needle reads 75-80 litre/hour which gives 48 knots on a 6.8 ribcraft.

I had loads of ribbing about getting such a large engine with ref to fuel consumption but this one is better than my old delta with twin 65's.

Bearing in mind the cost of 'go go juice' over there it's an important factor. I've short-listed the DF250 for next time. Let's hope the 'lecky' problems aren't going to be an issue. Roy's DF140 has recently been re-loomed.