Upgraded to a Stainless Steel Prop..

[Kylersk]

I had an aluminum merc prop, 13" with 19 pitch. If I was alone, in a 1750 Sportfish with 115 Optimax, I could get about 5200 RPM's and about 42-43mph on GPS. On the rare occasion I actually hit 44mph. With my family in the boat (wife and 3 younger kids) I'd barely touch 5000rpms and maybe 39mph.

So, I brought the original prop back and upgraded it to a stainless Merc Vengeance prop (13" with 18 pitch). I wanted to try it out tonight, but the weather didnt wanna cooperate.

I'm anxious to see what the drop in pitch and change to Stainless does....

[LMITOUT]

I went from a 4-blade 17P Trophy SS to a 3-blade 16P Vengeance SS and it totally changed my boat's performance. Gained around 600 RPM and 3-4 mph from my 90HP Yamaha. Best thing I did.

I was low on RPM's too and the drop in pitch with one less blade changed that for the better. You should see an improvement too I would think.

[JDM]

Let us know what it does for you. I have been thinking about doing the same thing for my 115 Opti. I am really curious how it affects your low end trolling speeds as well. Please report back.

[marine_man]

The upper limit on your opti I believe is 5750 - moving up in RPM's will definitely help you out in performance.

This information should be printed on the serial number tag that's located on your motor.

marine_man

[beeonkey]

Playing with props is the best way to get the best performance from your boat and motor. Look up the top rpm and match a prop that hits that rpm to just over it, you then have the prop matched to the boat. Check cornering and trim you will find a lot of difference in props and prop designs. A good dealer will be able to tell you about the prop size that will get close to the rpm’s. Different prop companies will also make a big difference, try them out. If you have a good dealer they will let you try it and if you don’t do any thing to it they will take it back and let you try another pitch or brand. Outboards today will cut out when the rpm’s are going to hurt the engine. Dealers love to put a prop that will not reach the max rpm’s because people don’t usually know, and a soom that what they gave you is all there is. Play with props and you can really make a boat come alive.

[Kylersk]

Just got off the lake and I think this prop is a big improvement. I was able to get on plane much faster with my family and solo. The boat also would hit 5500 rpm solo and 5200 or so with family in boat. I had a loose connection on my GPS so it kept kicking out on me so I didnt get a MPH with family, but solo I hit 43 mph.

So, It looks like I gained accelleration and didnt really lose any of the top end.