14.5x19 aluminum vs 15x17 stainless

[hollywoodwayne]

I have a 1976 seacraft masterangler with a 1995 johnson oceanrunner 150,the performance i'm looking for is a little better fuel milage the 14.5 x 19 alum is on there now and its got great hole shot and throttle responce oh yeah I have no tach.Will the larger diameter less pitch of the 15 x17 stainless give me a little better top end current top end is about 45 mph or will they be about the same

 

[Silvertip]

Re: 14.5x19 aluminum vs 15x17 stainless

Lets see -- you want more speed and better economy. What's wrong with this picture? No. You will raise the rpm about 400 revs and likely lose speed. At the same time you will likely burn more fuel. And just so you understand, 400 rpm does not translate to more speed. the 400 rpm increase is due to the fact that the prop is taking less bite on the water so it is moving you forward less than the 19 at the same rpm. Sort of like downshifting your car. Since you don't have a tach we can only speculate as to the result as I just did. Changing props without the information provided by a tach is a waste of money.

 

[steelespike]

Re: 14.5x19 aluminum vs 15x17 stainless

You could get a Tinytach It will work on yours and any other motor.
get us the prop size and the wot rpm and gps speed.We evan tell how well your setup works and what if any changes may help.