Which is the right prop?

[41 Keys]

Hi guys,

Question for you. I have a 19.5' 1980 Silverline with a Mercruiser 228 with 4bbl carb. My first boat. VERY HAPPY. I am third owner. The boat came with a prop of course but I want to know if the prop I have is the best one for the boat. I currently have a 3 blade prop. I don't know what the pitch is and don't remember the diameter. Thx in advance

 

[agallant80]

Re: Which is the right prop?

You are going to have to tell us the pitch and size of the prop for people to help. It should be stamped on the side you also need to know the gear ration of your outdrive which is stamped on the side of the outdrive. As for the proper prop it needs to be something that will put your boat in to the proper RPM at WOT. If you have a 228 it should be a 5.0L V8 with a WOT of 4000-4400

Try using the merc prop selector
Prop Selector | Mercury Marine


As for 3 blade or 4, 3 blades are better for top speed 4 blades are better for pulling tubers/skiers.

 

[jestor68]

Re: Which is the right prop?

The correct size prop is the one that allows the motor to operate within it's recommended 4200-4600 rpm range.

The ideal wot rpm in this case would be 4400 rpm.

 

[41 Keys]

Re: Which is the right prop?

The correct size prop is the one that allows the motor to operate within it's recommended 4200-4600 rpm range.

The ideal wot rpm in this case would be 4400 rpm.

Thank you. I am tied up at the moment and won't get back to the boat until 18th. Guy I bought it from told me top speed with one operator in is 50 mph. I can only wind it up to only 43 mph wot. Thank you for the quick reply. This forum is excellent. I thought I was on my own figuring things out.

 

[steelespike]

Re: Which is the right prop?

You need to adjust the trim for the best rpm and speed.

 

[scott8058]

Re: Which is the right prop?

People also tend to over state how fast is really is lol

 

[steelespike]

Re: Which is the right prop?

Prop size should be near the base of the blades or under the prop nut.
We need the prop size and the wot rpm and gps speed.Some cells have a gps app.
That setup is certainly capable of 50.