Prop suggestions for 2005 Sylvan V180 3.0L

[Salty Clark]

Hey everyone. New boat owner and have been lurking here for quite a bit to get some insights and general knowledge. In July, I purchased my first new to me, 2005 Sylvan V-180 bow rider with a Mercruiser 3.0L 4 cylinder and an Alpha 1 Gen 2 sterndrive. When I first got it, the tach wasn't working, so I just took it out and cautiously got to know her a little, then eventually ran WOT some. I took it to a recommended boat tech to give it the once over, change fluids, etc and had him install a working used tach he had on hand. Since then, I've had the boat out several times and noticed I am over revved with the current prop (if the tach that was installed is accurate).

Here are some boat specs:
18 foot open bow fiberglass hull runabout
1725 pounds dry weight without gear or fuel
30 gallon fuel tank
3.0l Mercruiser 4 cylinder (rated @135HP)
recommended WOT range: 4400-4800rpm
Alpha 1 Gen 2 outdrive with 2.0 ratio
GPS recorded top speed at 4800rpm: 34mph
current prop: Black Max 14 1/2 X 19 pitch 3 blade aluminum model # 8832830A45 (that is beat up and needs replacing)

With current load of gear, full tank of fuel and 2-4 people (including me) on board, I can easily hit 5000 rpm without being fully open throttle when trimmed up. I don't know what max rpms at full throttle is since I keep it at the top end of recommended WOT(4800) when running at speed. I am not currently pulling any toys, but may in the future. It feels a little lazy out of the hole, planes up decently, and then trimmed up, runs fine. I'm looking for prop help to get those RPMs down into the safe zone. Not looking to go stainless, as I like the safety factor of an aluminum prop. Better hole shot is a plus, more top speed would be gravy, but I'm currently fine with 34mph on the lakes we run on. Any insight or suggestions would be helpful, and thanks in advance!

 

[QBhoy]

I’d think that you could go more pitch on the prop by a couple inches perhaps. Try that and see how you go. You should likely get around 40 gps or a little over if you’re lucky, well trimmed and well propped.

 

[airshot]

I’d think that you could go more pitch on the prop by a couple inches perhaps. Try that and see how you go. You should likely get around 40 gps or a little over if you’re lucky, well trimmed and well propped.

I would agree based on information given. He is pushing a heavy boat so hole shot may not be great. My neighbor has a Sylvan 21' aluminum with the 140 hp 3.0. With a 21" pitch prop he can easily get 42 mph with a couple adults, but his has only a 18 gallon tank so even less weight. He normally only runs a 17" because he likes the hole shot when he has 4-5 adults on board and still gets 28 mph.