Fuel Consumption

[Aus Dave]

Hi guys I just bought a 2017 Barcrusher XS535 with a Suzuki 100A outboard. I took it out on the weekend and was a bit disappointed with the fuel consumption. Running about 4200rpm on calm seas the best I was getting was 2km/L. But the funny thing is we copped it on the way home, over a metre of choppy as, wind vs current and that didn't really change the consumption, only going down to 1.9km/L. My old boat with a yamy got me 4km/L at full noise. My fishing spot is 100kms away from the ramp so at this rate I'm looking at using the full 100L just in travel.

I'm thinking of getting a smaller prop as unloaded I'm maxing out at 5400 rpm.

Any ideas?

[Junky]

See if you can borrow a prop first. 

What is the rev range suzuki recommends?

If it's in the mid range now then you can try both bigger and smaller pitch props.

What size is on it now?

 

 

[Aus Dave]

Suzuki state the max range as 5000 - 6000rpm. At the moment it's got a rapture SS prop but I can't find the numbers on it. I like your idea about borrowing some other props, I'll ask around and see if someone has done spares and go for a quick run up the river. Cheers junky

[Aus Dave]

Ok I've found the size, it was on behind the nut. It looks like 13.25 X 21. I'll attach the best photo I could get

[Junky]

Yeah def borrow one. It sounds as though it is correct though. 

 

My merc 150 has the same rev specs but it's sweet spot is around 3700rpm. I get 1.9k's per litre @ 42kph throwing a 18inch enertia . That's pushing a 58 armour plate and they are a heavy boat.

If I increase rpm to 4100rpm then it drops down to about 1.5k's per litre. 

 

So maybe just back off a touch and see what happens there. You won't see the figures your old boat had though. 

Just out of interest, what was your older boat that was getting 4km/L? 

 

[jon]

Yeah what ever you used to have that got 4km per litre will near impossible to match with a 535 bar crusher. I’ve got a 6m centre cab and get any where from 1.4 up to 2.0 km depending on weather and how I’m driving and this generally Considered as pretty economical for my size boat 

[Aus Dave]

The boat I used to have was a 5.2m ocean pearl with a yamy 60 on the back. Very similar shape boat but a bit lighter. 800kgs vs 1200 kgs but the bigger outboard should compensate for that. With my old boat I didn't root around with fuel economy, I ran it at full noise the whole time. I'd love to have seen what I could have got if I tried. I also had a 5m stacer in the past with a 90hp Honda. That got the same if not better fuel economy.

If this is the best I'll get I guess I'll have to go buy a heap of jerry cans. Big boats I expect to be bad on fuel but I didn't realise small boats could be so bad too.

[AUS-BNE-FISHO]

Hey Aus Dave

Sorry, I'm not a boaty so can't help you too much...

Just thought I'd say welcome to the forum! 

Cheers Hamish  

[Aus Dave]

Hey guys I thought I'd give you an update. I had the outboard serviced yesterday and that had a massive affect on the fuel usage. I took her out today I  the river so I could take photos of what I was getting. So now my max WOT is up to 5700rpm and my fuel consumption at 4300rpm is 3km/L. I've chucked a couple of pics on. I have no idea what they did but it's way better. They reckon the fuel filter needed changing so that's their answer. I'm still thinking of dropping a prop size but this is a good start. It's only a new boat for me so I'll work it out. I'll keep you all posted on what happens

[Junky]

Good stuff. 

They must have flashed the ECU. Although flat water will give far better results than offshore in the swell. 

 

 

If you drop a prop size then be very careful of over-rev. You'll gain 300 to 500 rpm. 

[Aus Dave]

Righto thanks Junky I'll keep an eye on it. I think 300 - 500 is about all I'm chasing. I'll give it a go in the salt next time I go out and see what happens. I'm happier now but still reckon there's room for improvement.

[Bobs]

Bar Crusher 535C with a 90HP Yamaha is claimed to get 3.08 km/L at 3800 rpm dropping to 2.8 km/L at 4500 rpm. See

https://www.yamaha-motor.com.au/-/media/products/marine/outboard/power-reports/f90/bar-crusher-535-f90-16p-gp-alloy.ashx?la=en

I get about that with my 535XS in the river.

[Hweebe]

For comparison - I'm in a Bar Crusher 575c with a 100hp Yammie. (2012 model so its a bit long in the tooth now)

Best i get is around 2.3-2.5km / L in the sweetspot. I can only manage 2.5km / L if it is completely glassed out conditions.

Otherwise 2.3-2.4km / L is more the norm.

 

Not that it needs a repower but would be interested to hear if newer outboards run more effieciently by much?