volvo penta 250A

[Guest]

my recently aquired boat has a pair of 250A petrols, any one have aprox. fuel consumption figures for these engines ?? has been suggested 6 gallon per hour flat out. unable to check as gauge is a bit rough and ready. also what is the most efficent way to travel with a deep v hull (e.g. just on the plane and no more?)
these point are for the future as with the boat being new to me, it is full speed when possible and a lot of smiles.

 

[Guest]

This engine does not mean anything to me but on the assumption that the 250 refers to horse power (if its smaller what follows will be completely wrong), your 6 gals per hour flat out is very optimistic. You might manage that at a low cruising speed but not flat out. A reasonable rule of thumb for flat out cruising is about 1gal/hr per 12 hp so 250 would approximate to 20gals/hr therefore a twin installation is going to be about 40 gals per hour.

As to economical speeds, thats a bit of a contradiction in terms with large petrol powered boats but you will use less fuel per hour the slower you go. At say 8 knts you will be at the most economical in terms of mpg but faster than that you will lose fuel efficiency until the boat comes on the plane. Once planing the mpg will recover a bit and usually the most fuel efficient speed will be a few hundred revs above minimum planing speed - if you plane at say 15knts, 18-20knts will be the best compromise on fuel efficiency. Faster than that and the fuel consumption goes up exponentially.

If you are new to boating it would be wise to get some training as it will help you enjoy your hobby not to mention others you encounter on the water. Most people on this forum enjoy opening up their boats but just be aware that you make quite a large wash and racket when running at any speed and this is not apppreciated by many water users, especially those in small craft so give them a wide berth.

Enjoy your boating.

Nick

 

[Chris_d]

A good rule of thumb is 7-8gph/100hp(5-6gph for diesel). So your 250's, if that number is their horse power rating, will use 35-40gph flat out, thats £140 to £160 an hour at marina fuel rates, quite scarey!!
Cruising though at about 2/3rds throttle is usualy better, expect to get 1 to 2 mpg at a fast cruise. As for speed, up to about 7knots you will be very economical say 3mpg+, after that as you climb the hump the consumption will be awfull up to about 15-17knots where you start to plane and you start to achieve a reasonable figure of 1-2mpg up to at about 20-25knots, depends on your hull etc.
You will soon start to realise though why there are so many cheap twin petrol powered boats around, usualy with very low hours.

 

[Will_M]

The Volvo Penta 250A, the successor to the AQ151C.

4 cylinder, 4 stroke, SOHC
146hp @ 4800rpm – 5500rpm
2.49ltr cast iron block

Fuel consumption figures are exceedingly difficult to accurately predict, due to the many variables that have to be considered. Hence, these figures must be regarded as an estimate although they were based on actual tests.

Expected cruising fuel consumption per engine.
l.p.h g.p.h
250 / SP 30.00 6.60

Max fuel consumption at full load.
l.p.h g.p.h
250 / SP 43.00 9.46

The 151 / 250 requires a fuel octane minimum of 91, as such will run either Unleaded or Leaded fuel.


Hopefully that helps.

Regs..