Recomended RPM for 70 Evinrude

[stacer_seagull]

Hi Guys, i have a 70 evinrude on a 4.75 metre stacer and when i got the boat, i was told that the max revs i want to stay on is about 3800 to 4200, maybe up to 4500 wheni trim the motor, from what i have read,alot of people say i should be up around the 5500, if anyone has any ideas or opinions that would be great.
Cheers Brad

[Kerry]

Around 5500 is not what you really want to "stay on" but at least be able to achieve, which will indicate if the prop is correctly matched to the boat/motor combination.

If you can "achieve" around 5500 (or whatever the max WOT spec is for that motor) then running in the 4000 to 4500 range is a reasonably good operating (cruising type) rev range.

Cheers, Kerry.

[drevil]

;D

[stacer_seagull]

Cheers Kerry, it was what i was thinking as i can cruise comfortabley on about 4200 and get about 43 kpm on the gps, plus i will save a tad on juice as well.
Brad

[littlejim]

NS,

I reckon kerry has hit the spot.
My 70 evinrude (1989 or 1990 I think) seems to like sitting on 3 to 4 K revs. On the odd time I've left it on full throttle to hear the loud noise and show off, the overheat system has come into operation and spoiled the effect.

Most of the time (Jervis Bay) surface chop or swell mean that going at high revs just slams the boat, and its contents, unmercifully.

Usually I just get up on to the plane and throttle back to where it just stays planing, usually either side of 3000 revs. If it's rougher than allows planing just keep slowing the motor until the comfort level is reached.
Despite the dire problems mentioned recently on plastic 'trim tabs' fitted to the cavitation plates, until I fitted a pair, my old 4.5M f/g hull really took a lot of revs to get on to the plane. The wings took about a 1000 revs and a few seconds off the time to get on the plane.