Ford 120HP Fuel Economy

chasroberts

chasroberts

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I wonder if anyone can assist please? We are looking at purchasing a 15m powerboat fitted with dual 120HP Ford marine engines. In the short term at least she would be used to cruise the inland waterways. Now I realise that this is vast 'overkill' in terms of power needed but can anyone give me any sort of idea on consumption figures at minimum revs? I would envisage using alternate engines on alternate days or am I just being a plonker? Any advise would be much appreciated.

Many thanks in advance

Chas
 
2 x 120hp is quite low powered for a 15metre motorboat.
It will not be gong anywhere fast - so might as well go slow. But no so slow that your steering becomes vague.
I guess its on shafts/rudders so running on one engine may not be a pleasant experience.

If you could indicate a make and model of boat it may help to get a response from an owner of something similar.



.
 
We have twin ford 120 sabres and running both engines @ 1500rpm we use approx 20 litres per hour. Our boat is a 15 metre trawler yacht weighing 30 tonnes and at those revs average 7.5 knots. Very reliable engines which are easy to work on and very accessible for parts. Hope that helps.
 
Many thanks guys. As I'm not quite sure what I'm trying to ask it's hard to pose the question accurately. Don't want to say too much about the boat at present but it's a 15mt steel hulled motor yacht (not a true canal boat). Twin Ford motors which look in incredibly good condition and are described as 'immaculate' by the agent. I just think it might be expensive (and possibly damaging to the engines) to run them at virtually tickover in order to attain the sort of 8kph speed limits on most of the inland waterways. From what I've seen the boat appears to have been cruised extensively in open water as well. Just seems to be a lot of power for the canals and I'm wondering if I'll do more harm than good running the engines at that rate for extended periods. All thoughts welcomed - even the shooting down in flame sorts....

Chas
 
Hi Chas
The 120 Fords are naturally aspirated so would be fine at low revs. (The commercial version were used in tractors so good at low speeds). The problem can occur running the larger turbo versions at low revs as you can get a build up of oil in the turbo which then needs them to be opened up to blow the oil through. We have done weeks on the Thames and up on the broads with no problems at all. Personally I think they are fantastic engines as they are so economical.
Jenny
 
There are plenty of boats here on the River Trent with much more powerful engines .
Could I ask where you intend to be cruising?
 
R1chB1ch said:
We have twin ford 120 sabres and running both engines @ 1500rpm we use approx 20 litres per hour. Our boat is a 15 metre trawler yacht weighing 30 tonnes and at those revs average 7.5 knots. Very reliable engines which are easy to work on and very accessible for parts. Hope that helps.
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Hi RichBitch, curious as to what yr boat make/model etc.
 
MartynG said:
There are plenty of boats here on the River Trent with much more powerful engines .
Could I ask where you intend to be cruising?
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Hi Martyn. Cruising would be initially on inland waterways in France but I like the idea of being able to change cruising areas via open water if necessary. The boat was apparently not originally intended to potter around at 5knots hence my questions. Again many thanks for everybody's input and any more thoughts are welcomed.

Chas
 
France sounds good.
I believe the canals there are quite substantial ? If so perhaps there is a chance to give it a work out occasionally?

I would have thought a boat such as you describe would be quite happy going at an economical slow speed.


If its any comfort I have a turbocharged 170hp diesel and based on inland water with much pottering at slow speed and the occasional blast. In 5 years and 500 hours running = no apparent engine issues.
 
I have twin Ford 120hp in a 10mtr Birchwood. I cruised all the way from Le Havre to the Med, on the Paris to the Med part of the journey i alternated engines and ran at just over tick over for the whole journey. The only problem you will get is they will smoke after a few days. This will clear after a bit of a blast on the river sections.
 
R1chB1ch said:
Hi Chas
The 120 Fords are naturally aspirated so would be fine at low revs. (The commercial version were used in tractors so good at low speeds). The problem can occur running the larger turbo versions at low revs as you can get a build up of oil in the turbo which then needs them to be opened up to blow the oil through. We have done weeks on the Thames and up on the broads with no problems at all. Personally I think they are fantastic engines as they are so economical.
Jenny
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Sorry to be pedatic, but where does all this stuff originate from that Ford industrial base units were used in tractors.

Naturally aspirated industrial units used parent bore 107 mm non stressed block with 115mm stroke so were underquare engines.

Ford tractors used the 7A engine which could be linered or parent bore depending on what mood engineering were in, but both with 111mm bore and short stroke so were oversquare which for a tractor engine was simply nuts. However biggest difference was that 7N engine was designed from the outset to be a stressed member so block would be totally unsuitable for use in a marine application.

Tiny number of interchangeable parts.

Reason engines appear so economical is that only ten pennyworth of power being pulled out of them in the duty cycles quoted. Nothing to do with the base engine technology.
 
Latestarter1 said:
Sorry to be pedatic, but where does all this stuff originate from that Ford industrial base units were used in tractors.

Naturally aspirated industrial units used parent bore 107 mm non stressed block with 115mm stroke so were underquare engines.

Ford tractors used the 7A engine which could be linered or parent bore depending on what mood engineering were in, but both with 111mm bore and short stroke so were oversquare which for a tractor engine was simply nuts. However biggest difference was that 7N engine was designed from the outset to be a stressed member so block would be totally unsuitable for use in a marine application.

Tiny number of interchangeable parts.

Reason engines appear so economical is that only ten pennyworth of power being pulled out of them in the duty cycles quoted. Nothing to do with the base engine technology.
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That is what I was told by a marine engineer, and that they were marinised by mermaid, Lehman, Thornicroft and Sabre...
 
R1chB1ch said:
That is what I was told by a marine engineer, and that they were marinised by mermaid, Lehman, Thornicroft and Sabre...
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Typical of many of these guys, know nothing yard numpties, deal with them all the time.

Ford INDUSTRIAL engines were marinised by heap of people C Power, Lister and Watermota as well as those already mentioned however only Sabre and to a far lesser degree, Mermaid did proper engine development.
 
Hi im new . So as were on about ford mermaids im desperatly looking for a workshop manual for the 120hp with 24 volt wiring please mail me if someone got one for sale thanks darren
 
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