Lowering engine = loosing speed?

[bigboy]

Hey,

My boat runs 61.25mph down the stream. But sometimes it slips a lot. When I accelerate from start and make a turn it realy slips like hell. I've been thinking about lowering it for 1/2" of 3/4". Would this cost me a lot of speed?

At WOT i realy have to search with the trim where i have the most grip. You can feel it accelerating and holding in so this doenst sounds the best too? Maybe i could gain a mph because i have more grip or not?

Thx in advance!

[chris_lacey]

If you ventilate on turns or you have to fool with the trim to get a grip, you will probably gain speed if you drop the engine some.

[150aintenuff]

if you have a jack dropher about a 1/4" at a time and see what happens..

but you do sound a nudge to high.. atleast for your particular prop.. try others if you can to see if things improve

[chris_lacey]

Actually, yes, I should have said- for that prop.

[pyro]

Hold on, hold on... Why are you guys telling him his motor's too high? You don't even know how high it is yet!!

If he's talking about his Fletcher, which appears in his website photos as being a deepvee like a Larson with a buried stock lower unit and an aluminum prop... that changes everything.

If that's the case, for starters, then the first thing to do would be to try a better prop that can handle some ventilation and height without losing its bite. Aluminum props will gulp air and slip when you turn hard, they're best suited for outdrives. Lowering the engine will sacrifice speed and handling. If it's already in the 60 mph range, it likely needs to go higher anyway if it's on one of the lower hole settings. You may pick up enough RPM that a pitch upgrade may be appropriate.

Tell us more about the current setup. Motor height, measured as the difference between propshaft centerline and hull bottom at neutral trim. Stock lower unit? what kind of prop?

[bigboy]

Here you go Pyro:

Motor: 140V4 Rude (looper)

Stiletto 23pitch, 6100RPM + And 61-62mph with the stream and 56-57 against (there is a lot of stream here ) Gps measured and with 2 persons.

Gear case is standard. Bob's jackplate 5,5"

Propshaft is 4" under the V

Boat has 24° deep v.

[bigboy]

Nobody?

[pyro]

Try some better props, like I said. Or, roll the dice and have yours cupped a little for better "bite", but you may lose some RPM on top because this adds some pitch.