2002 Malibu Response prop key lost

[R44Ryan]

Had a 4 bladed prop on boat with LS1 when I bought it. Threw a blade off prop. Pulled prop off and dropped prop and key to bottom of lake. Any idea what size key ? Was curious what size prop they might of had too. We have a 3 blade to put on that they left to try but really liked what was on it. 

[UWSkier]

Probably had a 4 blade stainless, right?  Does the hub say CVP?  Those things are ticking timebombs.  Yours went off.  Lucky you didn't put a hole in your hull.

Put on an Acme 515 and don't look back.  It'll run smoother, give you way better holeshot, and probably similar top end.

Key is 1/4" key stock, chamfered on the ends that sit down into the shaft.  Square side goes against the prop.

[R44Ryan]

Thanks much on the info. I see the 515 is what is recommended too. I will get one coming. thanks again!

[justgary]

1 hour ago, UWSkier said:

Probably had a 4 blade stainless, right?  Does the hub say CVP?  Those things are ticking timebombs.  Yours went off.  Lucky you didn't put a hole in your hull.

I don't really know for sure, but I thought that CVP only made 3 blade props. 

[UWSkier]

37 minutes ago, justgary said:

I don't really know for sure, but I thought that CVP only made 3 blade props. 

Maybe. Thought there was a 4 blade cvp that came on LS1 boats bicbw

[justgary]

39 minutes ago, UWSkier said:

Maybe. Thought there was a 4 blade cvp that came on LS1 boats bicbw

My friend bought the upgrade 4 blade stainless with his '04 RLX, but it wasn't a CVP, it's an OJ 13x13 with cup.  He still runs it regularly.  I have a photo of it somewhere....

[R44Ryan]

What was the benefit of  a 4 blade? I can't seem to find any good info on that. 

[UWSkier]

12 minutes ago, R44Ryan said:

What was the benefit of  a 4 blade? I can't seem to find any good info on that. 

More blade surface area means more water contact. In some cases they can improve the wake for slalom a bit also. But since the advent of cnc props, 3 blades are really the way to go for most direct drive inboards. They have much larger blades than the older cast props. 

Edited June 15, 2020 by UWSkier

[SkiPablo]

i haven't tried a 4 blade on my boat, but i have the LS1.   The  Acme 515 runs 49 mph and the Acme 525 runs 48 mph.  I keep the 525 b/c we sometimes take the whole family out (7 people).   I'm sure there are some numbers on your old prop, but likely the 515 is the right prop for your boat.

[Pra4sno]

@jgouveia3 has a used 515 for sale

[justgary]

A four-blade prop *may* give better hole shot due to higher blade area. 

A four-blade prop *will* have a lower top speed (all other things equal) due to higher drag.

A four-blade prop might also have less vibration because the load is spread among more blades, but as @UWSkier mentioned, CNC props run fairly true and vibration free.

[justgary]

You may need to trim the key to fit.

Basically, the procedure is to put the prop on the shaft without the key, mark the shaft (a pencil will do) to indicate how far on the shaft the prop rests, then reinstall the prop with the key.  If the prop doesn't fit in the same place on the shaft, the key is too tall and must be ground to lower it.  Odds are that it will fit correctly without modification, but you should check before you run the prop on the boat.