Considering Prop Chg. on MERC 900

[kfrei]

I have a 78 Merc900 and am experiencing slow starts with skiers and a maximum of 4500 RPM at WOT. I have a stock propeller (I think 19P). Would a 15P or 17P help this at all. I believe that the Max RPM is suppposed to be 5000-5500. Does anyone know what the OEM prop is supposed to be and if Mercury has any official recommendations.

 

[JB]

Re: Considering Prop Chg. on MERC 900

Howdy, Clipper.<br /><br />Yes. A 17" prop would help a lot.<br /><br />Good luck.

 

[Kenny Bush]

Re: Considering Prop Chg. on MERC 900

Try the 17p and see if helps. You got the right idea. Get the max rpm's up to operating range.

 

[kfrei]

Re: Considering Prop Chg. on MERC 900

Thanks for the replies. Would a 15P or a 4-blader be out to lunch since we use our boat usually for watersports. Thanks again.

 

[Kenny Bush]

Re: Considering Prop Chg. on MERC 900

No: a 4 blade is used to get more bite. Tugboats use 4 blades. Personally I have not felt the difference in the 4 or 3 blades(I have both). If you use the boat for watersports all the time, then use the 15p. You should be able to pull your skiers right up and out of the water. You just lose the top speed. Are guys skiing up there already? We are just now getting the wetsuits out. Water temp is about 50 degrees this week and climbing.

 

[kfrei]

Re: Considering Prop Chg. on MERC 900

Thanks for the info Bushcat. You have a heatwave there compared to our 38degree high for today. Where we ski the ice should be off early May and all we can do is fish until end of june/beginning of july for water to warm up. Kind of pathetic, huh!!

 

[Mercury140-I6]

Re: Considering Prop Chg. on MERC 900

I thnk it's + or - 200rpm's for every size pitch you go up or down (Down = + rpm's and Up = - rpm's)<br /><br />Craig

 

[Clams Canino]

Re: Considering Prop Chg. on MERC 900

Id go with a 15p SS - 3 blade.<br /><br />-W