FRIB 360 outboards

[pilchardthecat]

Hi All, i'm yo-yoing a bit on outboard choice for my FRIB 360 which i havent actually bought yet because i cant make my mind up!

Cant decide between a 4-stroke (heavy, cant service it myself) or a 2nd hand 2-stroke (lighter, cheaper, can service it myself). I'd pretty much decided on a 2-stroke as weight is important but having done some fag-packet maths on range and weight of fuel it might not be that simple.

Assuming a 2-stroke weights 35kg and an equivalent 4-stroke about 45kg, and the 4s=>1 litre/nm roughly, the 2s=>1.7 litres/nm, then for a range of 15nm i'll need 25kg of fuel for the 2s and 15kg for the 4s..... so the 10kg weight saving is cancelled out by the fuel

I'm sure i'm not the first person with this dilemma - so i'm interested in anyone else's experience/decision

[chris moody]

For an F-rib 360 I'd be looking at the new lightweight Suzuki or Tohatsu 20hp EFI 4 stroke engines. I think they weigh in at just over 40kg, and they are going to manage a lot better than 1 litre per nautical mile.

My 50hp 4 stroke (EFI) manages to average 0.6 l /nm with a mix of cruising at 15 to 20 kts and some full throttle use at just over 30 kts. I'm getting 1.2 l / nm out of a 250hp 4 stroke when cruising at 20 to 25 kts. The new EFI 4 strokes are very fuel efficient.

[Paul B]

My Honwave T38 paired with a Suzuki 15hp 4 stroke did approx 65 miles on 12 litres, oh and the 9.9, 15 &. 20hp Suzuki’s are 44kg

[harrison]

Think you'll get far better economy than those figures. Assuming looking at around 20hp motors.

Even our 60hp/5m rib will give a good 0.5litre/mile for mixed use. I only know this as this as one day this week we did 47 miles and used just under 20 litres of fuel.

Never really worked out consumption on our previous sibs with 20hp efi 4-stroke motor as a 12l tank would last us most of the day. At the very least 0.3litre/mile and probably nearer to 0.25litres/mile unless we were towing.

Not surprised at all with Paul B's figures above - impressive.

As an aside, good practice for passage planning, work on the thirds rule. 1/3rd out, 1/3rd back and 1/3rd in reserve.

[ChrisParish]

Regarding servicing, if you buy a 4 stroke that is a few years old and out of warrentee then there is no reason not to service it yourself. It’s not much more complex than servicing a 2 stroke (unless I am missing something)

My 2007 9.9hp mariner gets around 0.2l/m, and that’s with me using WOT a lot. Fuel economy on smaller engines and light boats is superb.

[pilchardthecat]

For the 4 stroke I would probably buy new, so EFI and warranty I guess I would have to take it in for service (?)

Only needing 12 litres of fuel for the day evens up the weight a lot vs 2 stroke, and yes both would be 20hp as they seem to weigh the same as the 15

Does anyone run a 10hp with the 360?

[ChrisParish]

Yes, you would have to take it in for servicing in order to maintain the warrantee.
I run a 3.8m Honwave with a 9.9, which is a similar size and weight boat to the 360 and honestly, it is a tad underpowered - I have to push it hard, especially in a following sea. Of course, that could just be the boat.
There isn’t much of a weight saving going down to 10hp. Mine is 38kg which is only 6kg less than a Suzuki 20 (I think - it’s something like that anyway)

[chris moody]

Rule of thirds is a good one. This week I'm carrying two 25 litre tanks plus another 20 litres reserve. Should give me a range of 85 nm plus 40 nm reserve

[pilchardthecat]

Has anyone tried sticking V-Power in the new EFI engines?

Presumably Suzuki "lean burn" is electronic injection timing/knock sensing so in theory.....

[harrison]

We generally run Shell V-Power or BP Ultimate for all our outboards, both efi and carb. No performance benefit and in reality probably a total waste of money. Started using it because there were some rumours there is less ethanol in them, although no data to back this up so probably also total boll*cks!

More useful is we stabilise all fuel with Quicksilver Quickare and try to use fresh fuel each time, with any left over going in the other half's car. Last tankfull of the season is treated with Quicksilver Quickstore to protect fuel left in the lines, filters etc. over winter.

Totally OCD but good fuel management won't do any harm!