What prop for 1989 Yamaha 40 ETLF?

[hotkey]

Just bought used boat. Prop is chipped and I want to get a new prop. Existing prop has stamped "10 1/4 x 14-g. . . 0708" on the prop hub. It appears to be aluminum.

I'm a boating noob so I'm not sure what I should get. In browsing catalogs, like iBoats.com, I don't find a 10 1/4 in the Yamaha 40 listing.

Maybe someone can educate me on this process and suggest some replacements. Thanks.

 

[steelespike]

Re: What prop for 1989 Yamaha 40 ETLF?

Don't worry too much about the diameter if it is about the same 1/4" either way.
Now is the time to fine tune your selection.Do you now your present wot rpm and speed.If you read the stickies at the top of the page and the helps on the prop store page it will help you understand props a little better.We can help with any confusion.We'll be glad to help with a selectio.

 

[hotkey]

Re: What prop for 1989 Yamaha 40 ETLF?

Don't worry too much about the diameter if it is about the same 1/4" either way.
Now is the time to fine tune your selection.Do you know your present wot rpm and speed.If you read the stickies at the top of the page and the helps on the prop store page it will help you understand props a little better.We can help with any confusion.We'll be glad to help with a selection.

I dont know any rpm setting. WOT? Not sure what that means. And speed seems to be 27 MPH best. The folks at www.tacomapropeller.com recommended 11 3/8 x 12 to get out of the hole easily and not lose any speed.

 

[steelespike]

Re: What prop for 1989 Yamaha 40 ETLF?

I dont know any rpm setting. WOT? Not sure what that means. And speed seems to be 27 MPH best. The folks at www.tacomapropeller.com recommended 11 3/8 x 12 to get out of the hole easily and not lose any speed.

wot = wide open throttle.What boat do you have?Year,size,Brand,model.
Dry weight? Your rated rpm is 4,500 to 5,500.
wot should be close to 5,500.Depending on the boat your speed seems a little slow. You really need a tach to make a prop selection.Is your speed by gps? The antivent plate(just above the prop) should be visable on plane.A Tinytach is about $47 and easy to install.Is the hole shot slow?A 12" prop would improve hole shot.May or may not affect speed.

 

[hotkey]

Re: What prop for 1989 Yamaha 40 ETLF?

wot = wide open throttle.What boat do you have?Year,size,Brand,model.
Dry weight? Your rated rpm is 4,500 to 5,500.
wot should be close to 5,500.Depending on the boat your speed seems a little slow. You really need a tach to make a prop selection.Is your speed by gps? The antivent plate(just above the prop) should be visable on plane.A Tinytach is about $47 and easy to install.Is the hole shot slow?A 12" prop would improve hole shot.May or may not affect speed.

Aha! I'm learning tons from the forum!

15.5' Javelin 350A bass boat. I don't know any of the specs on the boat. No manual available either. Speed is from on board speedometer. The hole shot (with 2 riders) does not occur unless 1 rider moves forward.

 

[steelespike]

Re: What prop for 1989 Yamaha 40 ETLF?

Your boat is about 780lbs. Rated for 48hp.Do you trim in/down(prop closer to the boat) for hole shot?Is the battery(s) and tank in the stern?
It would seem that you do need less pitch;but without your max wot rpm and speed.Can't tell how much or if there is an underlying problem.Also can't tell if the prop change was successful.Check your motor height(antivent plate visable on plane)Prop calculation is only as accurate as the input.In the extreme correct motor height cold add rpm and 2 to 3 mph.

 

[hotkey]

Re: What prop for 1989 Yamaha 40 ETLF?

Your boat is about 780lbs. Rated for 48hp.Do you trim in/down(prop closer to the boat) for hole shot?Is the battery(s) and tank in the stern?
It would seem that you do need less pitch;but without your max wot rpm and speed.Can't tell how much or if there is an underlying problem.Also can't tell if the prop change was successful.Check your motor height(antivent plate visable on plane)Prop calculation is only as accurate as the input.In the extreme correct motor height cold add rpm and 2 to 3 mph.

Wow - did Google turn that up for you? Info plate reads rated for 50HP but I spose 488-50 is no big deal.

I do trim down to start out yes. 2 batteries and 6 gal tank are in back yes.

I did some Googling on what the antivent plate is but I'm still not totally sure. There are a few "surfaces" on the lower unit so I'm not sure which one it is. I did find forum posts suggesting using a straight edge to line up bottom of hull and the plate for best results but I guess I need to make sure I'm lining up the right part of the motor!