Isuzu 55 fuel consumption

[blackrose]

I'm outside white mills marina on the Nene heading for Lilford marina near Oundle. Canal planner says it's a journey of 10 hours 40 mins using their default settings and it's 17 locks, but I'm single handed on a widebeam so I think I'm a lot slower than that. 

 

I'm down to about 100 litres of fuel and I've never really known what the fuel consumption of my engine is. Getting into white mills to fill the tank tomorrow morning looks like a pain as I'm towing a dinghy. 

 

Even if the journey takes me 15 hours (2 days) I should have plenty of fuel right? I can't be burning anywhere near 6 litres/ hour at the low engine revs I'm using on this river.

 

[Tonka]

do you know how far down the pickup pipe goes as it may not go as far as you think

[blackrose]

This is also true. I can see the pipe from the outside of the tank but I've no idea what level it stops at inside the tank.

 

I guess I'll have have to make the difficult manouvre into white mills tomorrow morning to be on the safe side.

[blackrose]

I've roughly calculated that I used about 53.5 litres of fuel over a 17 hour trip so my fuel consumption was about 3.15 litres/hour at between 1000 - 1800rpm

[Tony Brooks]

7 minutes ago, blackrose said:

I've roughly calculated that I used about 53.5 litres of fuel over a 17 hour trip so my fuel consumption was about 3.15 litres/hour at between 1000 - 1800rpm

 

That serves you right chasing a huge engine up/down rivers

 

I think you have a Beta engine and if so its indirect injection, so you trade the clean idle combustion for inferior consumption at higher seeds.

[Alan de Enfield]

8 minutes ago, blackrose said:

I've roughly calculated that I used about 53.5 litres of fuel over a 17 hour trip so my fuel consumption was about 3.15 litres/hour at between 1000 - 1800rpm

 

That seems quite a lot for an inland waterway boat.

My 6-litre, 'straight 6' Ford 2725E engine uses ~5 litres per hour at 5-6 knots (1200-1500rpm)

[Tony Brooks]

18 minutes ago, Alan de Enfield said:

 

That seems quite a lot for an inland waterway boat.

My 6-litre, 'straight 6' Ford 2725E engine uses ~5 litres per hour at 5-6 knots (1200-1500rpm)

 

Bet you engine is direct injection, so won't suffer anything like the pumping losses at speed that an indirect injection engine will.

[Alan de Enfield]

4 minutes ago, Tony Brooks said:

 

Bet you engine is direct injection, so won't suffer anything like the pumping losses at speed that an indirect injection engine will.

 

 

Right again - you are good at this boat engine stuff.

 

Edited June 20, 2021 by Alan de Enfield

[Machpoint005]

Just a thought, but if the prop is optimised for canal speeds, won't that make matters worse on a river? (Always remembering that a widebeam has the hydrodynamic properties of a floating brick, not that a narrowboat is much better.)

[blackrose]

28 minutes ago, Tony Brooks said:

 

That serves you right chasing a huge engine up/down rivers

 

I think you have a Beta engine and if so its indirect injection, so you trade the clean idle combustion for inferior consumption at higher seeds.

 

Isuzu. It's in the title of the thread.

 

Is 55hp a huge engine? I'll try telling that to some of the people I've met in grp cruisers on rivers with their 320hp engines. Costs them 20 quid just to start them up.

[blackrose]

13 minutes ago, Machpoint005 said:

Just a thought, but if the prop is optimised for canal speeds, won't that make matters worse on a river? (Always remembering that a widebeam has the hydrodynamic properties of a floating brick, not that a narrowboat is much better.)

 

My prop is optimised for increased revs and power. It was overpitched previously was losing a lot of revs in gear. Reducing the pitch has resulted in more revs and more power. The torque curve for my engine is pretty flat so increasing revs hasn't resulted in a loss of torque.

 

I wouldn't argue with your point on the hydrodynamics of canal boats.

 

38 minutes ago, Alan de Enfield said:

 

That seems quite a lot for an inland waterway boat.

My 6-litre, 'straight 6' Ford 2725E engine uses ~5 litres per hour at 5-6 knots (1200-1500rpm)

 

Yes it does seem like quite a lot, but it's pushing a big boat.

Edited June 20, 2021 by blackrose

[Tony Brooks]

13 minutes ago, blackrose said:

 

Isuzu. It's in the title of the thread.

 

Is 55hp a huge engine? I'll try telling that to some of the people I've met in grp cruisers on rivers with their 320hp engines. Costs them 20 quid just to start them up.

Its still indirect injected I think.

[Mike Adams]

Most diesel engines when working in their optimum rpm range burn a similar amount of fuel for the hp produced. I find my Isuzu 55 reasonably economical. If you have a slug of wide boat in a shallow canal or small river then anything over about 2mph is going to use a lot of fuel. Remember they are not designed to move except a short distance every 14 days!

[blackrose]

35 minutes ago, Tony Brooks said:

Its still indirect injected I think.

 

Yes, that's right.

 

From the fuel I just used it was somewhere between 2.9 - 3.1 litres/hour.

Edited June 20, 2021 by blackrose