2001 180 Diablo with 3L Merc Specs?
 

Hey guys, does anyone know what the RPM range should be at WOT? I am currently running this prop:

Diameter: 14 - 1/2”
Pitch: 19”
Blades: 3
#992004

as it came with the boat. I had it out last weekend and the boat seems slow to get up on plane with 3 people on board. Also my max RPM was somewhere close to 4900. I didn't have the gps to check speed.

Any suggestions with regards to a different prop, pitch/size/4 blade, would be great.

thanks :wink_thumbup:

Re: 2001 180 Diablo with 3L Merc Specs?
 

4400 - 4800rpms is the range for the 3.0L. If you are at 4900 it will be difficult to change the prop to get more holeshot because you will need to decrease your pitch which will cause your rpms to rise. And increasing the number of blades will do the same thing unless you increase your pitch to offset it.

Have you installed a set of Smart Tabs? That would be my first recommendation. Second is to move any unnecessary weight (ie stored items or 'heavy' passengers) from the stern to the bow of the boat. Third, when was the last time that engine had a tune-up?

Re: 2001 180 Diablo with 3L Merc Specs?
 

Thanks Mikeyt,

I think your right about the weight, most of it is in the stern which would account for the slow to plan. Do you think I should move to a 20+ pitch prop to lower the RPMs? I bought the boat at the end of last season so I am not sure when the last tune up was. I did the oil change and winterizing myself. Replaced the thermostat and the plugs and added a water fuel separator thus far. I also cleaned the flame arrestor and lubed everything.

Thanks

Re: 2001 180 Diablo with 3L Merc Specs?
 

The problem with inceasing the pitch to lower the rpms is that your holeshot will suffer & it will be even more difficult to get onto plane. You could go to a 20" 4 blade prop which would keep your rpms about where they are and you might even gain 1mph at top end but i suspect the extra drag of the 4 blade will offset the 1" increase in pitch and any gain will be very small. I would suggest if you can borrow such a prop from a friend or find a prop shop that will let you try one out though, it might be worth while doing.

Other than that, i suspect the Smart Tabs installation and reorganizing your weight distribution will provide the most improvement.