Prop size question

[snookhooked]

I have a 1976 20ft Mako that I am putting on a 1992 150hp Evinrude spitfire. for this boat Im looking to save on gas use but enough speed for things like bad weather or things of that nature that can rise quickly while in the gulf. I dont was to be sluggish when I need to get out of there. any suggestions would help here is the model number of the motor if needed. #E150ELENC. Thanks

 

[steelespike]

Re: Prop size question

Read the stickys at the top of the page.
We need the present prop size,max rpm and speed.

 

[Dhadley]

Re: Prop size question

Thought you caught this in the other thread but my buddy has that same rig. He's running a 17 or 19 ss Turbo depending on load etc. He really likes the 4 blade 18 Turbo for overall use. We added a Bob's manual jackplate to get the most out of the set up. Without the plate I'd probably go with either the 17 or 19 3 blade. The 17 if you'll be loaded or a 19 if you'll be running on the lighter side.

 

[snookhooked]

Re: Prop size question

It doesn't have a prop so I don't have something to fall back on but wished I did. DH I did but wasn't for sure on which one. the best I can say is that most of the time it would be my daughter and I with the wife when shes off. I need to do more information on props. I just don't want to make a mistake when buying a prop and find out I made the wrong choice. whats the difference between a 17 and 19?

 

[Silvertip]

Re: Prop size question

The difference between a 17P and 19P is two inches of pitch. As DH indicated. The 17P is preferred if the boat is heavily loaded most of the time. Better hole shot but at the cost of reduced speed. The 19 is preferred when lightly loaded. It will provide higher speed at the cost of hole shot. The best prop is one that allows the engine to rev at the manufacturers recommended wide open throttle rpm with what you consider an average load. Again, if the load is heavy, you select less pitch. If you normally run lightly loaded you can use a prop with a little more pitch.

 

[snookhooked]

Re: Prop size question

Thanks, that has really helped me to understand and make a decision on a prop. I need to find out more about what this motor calls for. my thinking is if I add my wife and child and including my weight. that would be around about 550 lbs. that I would think would most likely be a light load for this motor. Im going to try and find out what a 76 mako would run in weight. I think its around 4,000 lbs but I will look it up and see what I can find. Thanks for this information it has given me some insight and a better idea. you guys are great and Thankful for having i boats form to help us rookies in the boaters world. Thanks again guys. Ok I found the Mako website that list this boat. posting it here. this is it. 20 20'-0" 8'- 0" 9" 20" 1775 lbs 44 Gal. 200. 8-0 thats beam and 9" Draft. 1775 is weight( I was way off on guessing it) this is the boat specs.

 

[Dhadley]

Re: Prop size question

If the only weight shift is either you by yourself vs. adding the wife & child, that probably won't require a prop change. If youre more concerned about possible top speed, go with a 19. If holeshot (& maybe pulling a water toy) go with a 17.

All this is assuming the motor will be running corectly, the set up is correct and you're using a good quality ss prop like a Stiletto.

 

[snookhooked]

Re: Prop size question

DH. ok now I have another question. Ive been looking at props on ebay and other places. not they will use the term like 17 x 14 1/4. what would I look for in the other part of the prop size. Im thinking that 19 sounds more like what I would need but would it have to be any certian size like 14 1/4 or is that not a major concern in looking? I ve seen so many difference on that and it does confuse me seeing that I dont know anything about picking a prop for a motor. Thanks

 

[steelespike]

Re: Prop size question

Prop size is allways given in diameter X pitch. diameter first.
Generally diameter is a product of the prop design.If the prop is listed for your motor the diameter is correct.Diameter isn't generally considered except in certain very specific applications.Stainless props are very good but expensive.If your starting without a prop you might considered a prop like a Hustler aluminum.These deliver close to stainless performance at aluminum prices.

 

[snookhooked]

Re: Prop size question

Thanks. that answered my question and I fully onderstand that.cool. this would be the first prop with me. it doesn't have on on it now. I just wanted to make sure I didn't by something that wasn't right for it and what I plan on using the boat for. Thanks