[Campnc]

I have a 3.0 OMC on a 87 Bayliner. The boat came with this totally worn and busted prop on it with no numbers at all and also one in the boat that looks different with the numbers 13 1/4 X R17. What kinds of props can I use on this type of outdrive? Is there just one size I can use or what?

[WillyBWright]

You have a Cobra drive, so you need an OMC compatible prop. Many brands these days are adaptable to multiple manufacturers. You just need the right hardware kit. Click on the OMC Cobra Props link above.

[Campnc]

How about the pitch? Do I get to choose and how do I know what I need?

[Silvertip]

There are two critical dimensions for a prop. Diameter (the size of the circle it forms) and pitch (the theoretical distance the boat moves with each revolution of the prop). A 17P prop theoretically move the boat 17 inch with each revolution. But since the prop operates in water, that is only theoretical and therefore there is slippage to contend with. Diameter is important because a prop that's too big around will hit the trim tab or the antiventilation plate. The hub is also important (the engine side of it) as it must match your outdrive. Click on the link below which is right here on iBoats. Enter you year, model and HP and you will be given a list of props. You would probably pick one from the middle of the list, unless someone comes by that has the same boat, same drive, same engine, and same year and oprates with the same load you do. Ideally you want to end up with a prop that when you run the boat wide open, the engine operates at or very near the maximum recommended wide open throttle rpm (4400-4800 rpm) for your engine. I don't think the 13-3/4 inch prop you have is correct for that boat.

http://www.boat-props.com/propellers...****=046505787

[kwikrnu]

I'm not a prop expert, but I did buy a boat almost 2 weeks ago. This came out of my omc book.