prop question for 500 EL thunderbolt 4cyl

[flatcat77]

i have a 500 merc i'm getting ready to do a prop swap on. its on a 1648 16.5x72"at floor. it weighs about 500lbs without the motor on it. i'm thinking i should be able to push a pretty big prop with my hull considering its weight and my motor having enough power to get it up on plane fast still. the prop i have is the stock 1975 prop. 3 blade...... well 2 1/2 blades. i'm not even gonna go run it with that on there. any suggestions would be greatly appreciated. thank you. Matt

 

[corm]

Re: prop question for 500 EL thunderbolt 4cyl

Hi,

Merc never had a stock prop that came with the engine. It was the Dealers responsibility to put the correct pitch prop on to allow the RPM to be in the 4800-5500 range. So the best way to achieve that is with a tach and a couple of props. I used to have a 50 on a T14XL that weighed in about the same as your FB. I ran a 13" but could turn a 15" I would check the pitch on the prop the rig came with and start there.

btw, my engine was several yrs older than yours. Yours will have a little more power than mine did.

 

[steelespike]

Re: prop question for 500 EL thunderbolt 4cyl

There should be a number on the barrel or under the prop nut.
I would start with the same size. Then get new rpm and speed figures.

 

[hwsiii]

Re: prop question for 500 EL thunderbolt 4cyl

Flatcat, you have not given anybody enough information to help you with your problem. They need more information.


H