Omc 60hp triple 1995 rpm's with a 5 inch lift jack plate ?

[phillnjack]

evinrude 60hp 1995 triple
model BE60TLEOC.
once i get a jack plate and get this engine up about another 4 inches what would be the
optimum revs to get for maximum power ??? i will try to get the prop to suit the revs,even if i have to cut it down myself (im thinking about doing that already and take it to 12 3/4x23)
i know its what some call the clubfoot gearbox, but i just want to see what can be done with
what i have.
its not a racing boat its just i want to be a bit quicker than it is.

I take it that the revs will go up once a jackplate is fitted and engine raised ???
what sort of revs more would it go to compared to running fully submerged ?
What i plan is to have the centre of the bullet just 1 inch below the boat for top speed.
at the moment ive got cav plate just 2 inch above, and getting 5500 rpms from a 13 3/4 x23
semi-cleaver.
this prop is not a problem for the engine to spin up from idle, it just dont get full revs top end
and ive been told the prop likes to run high !!!!!

By taking the engine up another 4 inches what rev changes should i expect to see ?

i want to get this to 50mph, just the once would be good.

at the moment with the omc 13 3/4 x 23 semi-cleaver it works out around 19% slip @5500 rpms.:mad:
i am thinking getting it up might get more revs and less slip !!!!!!!!!!!





phill

[phillnjack]

surely someone must know the idel revs for this engine with a jack plate and the engine up to have the
centre of the bullet level with bottom of the boat. ???

Ive been told the rev limiter can be anywhere between 6500 and 7000 so would this be what im trying for
maximum revs ?
or is the powerband at the 5500 to 6000 rpm range.

no point screaming the nuts off the engine if im not going to developing power at the revs.


phill

[shenders]

Check the factory spec’s. They should list the max RPM’‘S for that engine. I would say around 6000. No more.

[phillnjack]

ahh so the raising the engine up dont let me rev more, just allows a bigger pitch prop to spin upto the revs.

any ideas on how much more revs would be by raising the engine up an extra 5 inches or so.

at the moment im getting around 5400 to 5500 rpm swinging a 23 inch pitch x 13 3/4 silver streak semi-cleaver.
would taking it up gain another 500 rpms and would this give more speed or just rev higher with more slip ?

im not looking for crazy impossible stuff that a lot talk about about and dream about, im after the engine running
well within its powerband and getting the max performance from the prop.

at present the 23 pitch is just 1mph faster top end than a 19 pitch sst ,the semi-cleaver is having a lot more slip.


jack plates and running surface props is a totaly alien thing to me, ive always used fully submerged props and
found they were the best for what i used the boat for, like when pulling toys and for ski-ing etc.

Now i fancy going the other way for a change and look for the best top end from what ive got.

[fs5]

is the 23 and 19 the same style of prop?
if your getting 19% slip from your 23 ,i'd try adding some cup,especialy if your goin to raise your motor.
maybe you should try a omc srx prop.

[phillnjack]

high fs5
the 19 inch prop is a omc sst 13x 19 stainless steel prop from the early 1970's, one of the very first omc factory race props with teflon coating.
i took the teflon off and polished the prop due to teflon coating eroding and rusting after all these years.
This prop gave 5700 rpms @38.3 mph = 25% slip


the semi-cleaver 23 inch prop is a omc silver streak 13 3/4 x 23 pitch.
these props were called silver streak when painted with a metalic finnish and then renamed SRX when polished.
So the 23 prop is actualy a OMC SRX PROP now its had the silver metallic paint removed and satin finnish !!!!.
part number of the prop is omc 388884 . this gives 5500 rpm's @ 39.8mph = 19.6 slip

the part number for the alloy 12 3/4 x 23 prop that was realy crap is 390895, this prop gave huge amounts of slip on the holeshot and only got the boat to 5400rpms and 36.1 mph = disgusting 25% slip

all my figures of slip are presuming my gearbox ratio is 2.42 to 1. !!!

the speed results are not as high as using the 19 pitch on the lowest setting for the engine.
also when down much lower i got more bow lift at top speed with the 19 sst.