Prop question

[TiPo]

I recently bought a 20 Odessey pontoon boat with a Honda 75 hp 4 stroke engine. It had a 14” 13 degree prop but was in bad shape. My tach was not working. I put a 4 blade 13 pitch and replaced my tack and only getting 4400 rpm wot. Any suggestions? I think 11 pitch? Need some advice please. Thanks

 

[jimmbo]

What's the WOT rpm range for that engine?

 

[Sea Rider]

Need to dial a prop that revs middle to max wot rpm range factory stated as usually loaded. Need to check factory mim-max wot rpm range and go from there maximizing props to achieve any of both top boating cond.

Happy Boating

 

[TiPo]

Max rpm is between 5000 and 6000 wot.

 

[WesNewell]

4400 rpm is really low. Are you sure you set the new tach to the right setting for your motor? If so and it's reading correctly, then yes, you need a lot lower pitch prop, assuming your engine is running right.

 

[Sea Rider]

How loaded was combo when tested ? 4200 wot revs as loaded is way low. Engine is 1300 from middle and 1800 rmp from max wot range. Is engine in excellent running cond ? If so, current prop seems is on its way to become fully spun or already shot.

Happy Boating

 

[ahicks]

I recently bought a 20 Odessey pontoon boat with a Honda 75 hp 4 stroke engine. It had a 14” 13 degree prop but was in bad shape. My tach was not working. I put a 4 blade 13 pitch and replaced my tack and only getting 4400 rpm wot. Any suggestions? I think 11 pitch? Need some advice please. Thanks

I have a Honda 90 on a 24' 'toon. The 14x13 Honda prop I have was turning about 6100 rpm with a light load (just me). Just changed to a 14x15 (found a deal too good to pass on) to get 5500 which I like much better for all around use.

Point being, I'm surprised to hear that your 75 on a 20' boat will only turn 4400 - even if your boat weighed more than mine. The 75 and 90 hp engines are nearly identical. I would have expected the 75 to do much better, making me wonder about the accuracy of the tach as well. While wondering, are you sure about the prop size you have now?

Unless you spend a lot of time towing, I would suggest 5500 as a good target rpm.