Mercruiser 3.0L 140 HP Prop Suggestions

I am in need of a better performing prop for my application.
Specifics:
Boat: 1982 Thompson Sea Lancer 184, 2200lbs
Motor: 1982 Mercruiser 3.0L 140HP 170hrs (yes that is right, original & mint)
Current prop: Mercury SS Vengeance 21p
Current test results: WOT 4400 with 39.8mph (GPS)
4 adults and 5 kids holeshot is terrible

Needs:
I am in need of better acceleration with passengers in the boat. I am aware that my WOT range is 4400-4800 so I can pitch down and not overrev the engine. What are people using for props that are helping holeshot but not necessarily killing top speed?
I do travel the bay of Green Bay to Door County (45 miles) several times during the summer and would not like to have be turning 4000rpm to get 30mph.

All suggestions welcome.

Re: Mercruiser 3.0L 140 HP Prop Suggestions

First, you need to understand the propeller is the transmission for your boat -- and it only has one gear. So -- you can't have it both ways. You either have hole shot or top end. Anything in between is called compromise. Although I'm not familiar with your boat, four adults and five kids is a pretty good load for an 18 footer (if that's what the 184 stands for). Not only that, but its a load for the engine as well. To give you better hole shot, you need to pitch down (probably to 19P to get revs up to 4800. Given those two numbers, speed stays the same. Yes -- the engine runs faster but remember, you just downshifted like you would in your car. Revs go up but speed stays the same if you hold the same throttle setting. Also be aware that when you prop for a heavy load, the engine will easily over rev when there is only one or two of you in the boat.

Lastly, even though the engine only has 170 hours on it, make sure it is tuned up properly. Running well is not an indication of proper tune. Things like the throttle not opening fully is just one thing to check. Ignition timing is another.

Re: Mercruiser 3.0L 140 HP Prop Suggestions

A bolt on Doel fin (hydrofoil), or Smart tabs, will put you on plane quicker, and hold it there easier, and improve your holeshot some. I'd say a well designed 19" pitch prop will give you better holeshot, maybe even more speed while staying within your rpm range. There are prop guru's here who could probably turn you on to exactly the right prop if they chime in. good luck