not sure were to post question ?

[recoil]

hello all
its a ski / prop question we have a 1978 winner wild cat ?

we've done a lot of work on the engine originally 260 hp mercruiser 5.7Lt v8 now nearly 400hp
the boats got a 5 bladed SS prop 14 1/4 by 23inch pitch , i would think having this horse power the engine would not be over propped but it struggles on the deep water starts , its dragging me about 100 yard on the mono , if you don't push the throttle full open , and just push it 1/2 it pulls a bit better , the boat tops out at 50mph , should we prop it down ? i don't wont to lose too much top end as next year wanting to start bare footing
any help

 

[skibrain]

Re: not sure were to post question ?

Lots of places to tie on to that rig!

You will have more engine/prop specific input posting this elsewhere. Knowing what your current RPM is at wide open throttle would be helpful and is the first question you will be asked.

Dropping to a 21" pitch is likely going to help hole shot. Even if it compromises top speed a bit or if you have to watch rpms up top, 50+ is plenty of speed for footing. if you're not getting the upper rpm range with the 23" maybe it would even be faster with a 21"

Not many ski-specific boats running i/o's so I don't know how the final drive compares, But the older outboard-powered (mostly 200 hp 2-strokes) barefoot boats commonly run 19" 5-blade props. This limits their 65 mph potential to closer to 50 mph, but gives a mighty hole shot.

Is the prop in decent shape?
Trim down all the way?
Modified engine is soft at lower rpm and makes it's power up top?
8 big friends sitting in the back of the boat?
You weigh 350 lb and are on a 62" ski?

I would think 400 hp should get your skier on plane in about 2 seconds.

 

[rabiddawg]

Re: not sure were to post question ?

I don't know a whole lot about prop stuff, but I do know a good bit about small block chevys. Since you modified the engine you will certainly need to modify the carb and ignition to take advantage of all the extra horses.

Without know more about your setup any advice will be a shot in the dark.

 

[recoil]

Re: not sure were to post question ?

rabiddawg
hi m8 maybe i can pick your brains
260 mercruiser small block ,
here's a list of what we've changed
eagle crank billet steel
high lift cam
flat top piston
dart cylinder heads ported 30 degrees i think one 2in one 1 1/4 i think
edelbrock manifold
no alteration to crab or needles
felpro gasket set
i think the head alone gave use 40 extra hp
maybe the engines turning out 350 not 400
any help would be appreciated

 

[snaggle]

Re: not sure were to post question ?

hi im recoil's bro the only mistake he has made with this if i remember right is stating its a high lift cam if i remember correctley its a marine cam and it also has a torquer 2 inlet manifold and is fitted with the standard ( if brand new ) mega flash ignition system and a holley fuel pump . i also seem to remember that the cylinder psi when tested cold was around 210 psi

im sure recoil will correct me if im wrong on this look forward to your thoughts