rpm ??

[Tim Powell]

Is there a rule of thum. My 892 turn at the dock no load both of them exactley
2475 by the mechanical tacks. Now what should the boat cruse at i have heard all kind of numbers.
what rpm should top end be and what should be cruse rpm be
what the answer Scott???

[Boatsb]

I think 2150 to 2200 under load but thats a Dave question.

FWIW I know of onethat hit 30 mph wot at a seatrial.

[Tim Powell]

i think 2150 to 2200 under load but thats a dave question.

Fwiw i know of onethat hit 30 mph wot at a seatrial.

do you know what props were under it if not can
you find out??

[saltshaker]

2300-2350rpms WOT loaded. Cruise is subjective. 2150 would be the factory rated cruise but most run them a bit slower. You can cruise at 2150 but you won't get the same hours out of them as if you run them at 1950-2000rpms. It all boils down to the amount of fuel burned. There's a range of gallons burned between overhaul. If you run them slower, you're burning less fuel and therefore will get more hours. If you want/need that extra speed running them faster will burn more fuel and hence give you fewer hours between overhaul. For me I find that as long as you are propped right and you're not running at all hot, 2000 rpms seems to be the sweet spot. They really come to life at 1950. We often cruise at 1750 when running distance but I think that's dogging it a bit. All this is based on being propped right. If you only hit 2200 max then you're running harder even at a slower cruise like 1950rpm. You have to think of it as percentage of full load. RPM doesn't follow load exactly but you get the idea. Tim didn't yours hit 26kt at sea trial? That's just about 30mph.

[Boatsb]

do you know what props were under it if not can
you find out??

I think michigan cncs. Ill try to get the details for you.

[Scope]

2500 rpm no load and 2300 loaded.

[Spellbound]

Tim....I ran my 8-92's @ 1850-1950 cruise, kept the heat out of them and when swapped out for the QSM's had over 3k hrs on them and they were still running strong with no smoke at start-up.

[rsmith]

Is there a rule of thum. My 892 turn at the dock no load both of them exactley
2475 by the mechanical tacks. Now what should the boat cruse at i have heard all kind of numbers.
what rpm should top end be and what should be cruse rpm be
what the answer Scott???

It depends on your load. There is a huge performance difference between full fuel water supplies and people and even half tanks and light loading.

[Tim Powell]

Tim....I ran my 8-92's @ 1850-1950 cruise, kept the heat out of them and when swapped out for the QSM's had over 3k hrs on them and they were still running strong with no smoke at start-up.

Toby do you remember the prop size?

[Tim Powell]

It depends on your load. There is a huge performance difference between full fuel water supplies and people and even half tanks and light loading.

I will agree 100% Scott if i make a long runn and as fuel load decreases speed picks up at the same rpm.