4 stroke cruising revs

[Good_as_Gold]

gday
just wanting to see anyoneelse crusies at above 5500rpm with their 4 stroke.
I constantly do so if conditions suit .
since mine is only 60 HP fuel economy is not a real issue.
I have 280 hours clocked and it has never missed a beat.

[thylacene]

Our redline is 6100, revs to 6000 @ WOT, 5500RPM is just over 35 knots for us, and that is too quick for South Coast NSW seas on all but 1 day a year. Usually run our 175 @ 4000 RPM thereabouts when seas allow, but spend more time between 3000 & 4000RPM.

[MikeyS]

My DF-150 cruises most comfortably and economically a bit over 4000 and that's where I tend to stay.

[FNQCairns]

Rule of thumb is the very speed that gives you the best km traveled for the litres used is your ideal cruise speed. however much extra fuel you choose to use with higher cruising speeds is up to you.

Another rule of thumb because while technology changes the physics still has not and until mass produced technology changes enough....cruising at above 80% of total HP output is doing your engine more harm than good.

[Flex]

Thats one advantage of two strokes thats often overlooked, The ability to run at redline all day long. No valves,belts,rods etc to mistime and cause issues.

im sure if you have your motor serived often I cant see you having any problems what so ever, only issues with 4 strokes is "If" there is somthing wrong then its made worse through their running mechanisms,like a car engine, its a hard life if your running it close to redline all the time.

But Im sure for 99% of 4 stroke owners, its in their design to run at that range so you shouldnt have a problem IMO.

[Micadogs]

My best cruise range is 4800 - 5000, best Klm / litre etc at that RPM. Approx 45 - 48 klms / hour.

[Good_as_Gold]

At 4000 to 4500 Im doing about 40km/hr at 12lt per hour , but I try not to look at the fuel flow when wot some times you just need to get to the spot as quick as you can .Or more important when your three hours late getting home.

[PADDLES]

my 140hp, 4 cylinder suzuki used to seem happy at 4200rpm, my 220hp, 6 cylinder mercruiser seems happy at 3500-3800rpm

[odes20]

I run my Suzuki 175 4 stroke at 4400 -4600 for cruising to and from the reef. It can WOT at 6100 on my boat so my revs are OK do you think??
John

[GLXMAN]

I have a 60 HP 4s Merc pushing an Allison 4.95 SC
I have been concerned about the same thing,

To achieve an reasonable plane and cruising speed, I require 4200 revs, sometimes I can squeeze it at 3800 but the conditions have to be glassed out

WOT is about 6500, asked the dealer about 4200 and he said it was OK, lets hope he is right

Regards,
Gary

[OPTI]

i would think 4000 rpm would be max cruising rpm ,anything over that will be using lots of fuel .one of the problems with the 4 stroke is its weight and we are now seeing boats being under powered to keep the heavier 4 strokes on the transom,some boats would be much better off with a di 2 stroke ,peformance wise and economy wise.