Am I over propped?

[Sdfish]

Hi guys, just got my motor service at 174 hours. I asked they print out the engine data and was surprised at the RPM numbers. No data in 5,000 to 6,000 rpm range. I don't run the boat hard, but I think I may be over propped?

I will take it out in the next few weeks and push it to the higher RPM.

Not sure what my current prop is, it is stainless with a 15-M marking on it. There are no stamped numbers in the hub.

Boat is a 1999 GW Adventure 208, with a Yamaha F150
I typically fish with a full tank of gas, full 32 gallon bait tank, located near the transom, 60 lbs of ice and 2-3 adults.
It gets on plane fine and I can run 4200 rpm and get 20-24 mph.
Average MPG is 3.
My max recorded speed is 37.5 mph.
This is lower than the performance data that GW has posted.
My trips are all offshore, so I hardly ever go full throttle.

Am I over propped? Any suggestions?

Thanks in advance!

 

[Doc Stressor]

You are running quite a bit heavier than the factory test boat. With only 150 hp, performance falls off fast as you increase the weight of the boat. Try running the boat with just yourself and a half tank of gas. As long as you can turn over 5500 rpm at WOT, you are not over-propped.

If you have not accumulated at least 1 hr at the higher RPMs, the engine log will read 0 hr.

 

[seasick]

The specs for the prop are often stamped inside the inner hub. That means that you have to remove the prop to see them.
My 208 with similar motor and same prop barely makes 5000 revs WOT. It's been like that for many years. Top speed is about 32 knots (GPS speed). If I play with the trim I can get maybe 5200 revs.
I rarely and I mean rarely run at WOT. Most cruising is at 3600 to 4200 revs. 3900 revs makes about 23.7 knots with half tank gas, two persons total.

 

[Sdfish]

good point less that 1 hour over 5000 rpms. I dont push the boat that hard at all and only can open it up in the bay.

 

[trapper]

Before installing my F200 I was running an F150 on my 208 with a Reliance 3 blade 141/2x 15 p prop. Getting 42 mph at WOT of 5800 rpms. That was with a full tank fishing gear and my wife. No bait tank and no ice. No hardtop.

 

[Sdfish]

OK - I ran the boat this weekend and with a full fuel tank, full 32 gallon bait tank, 2 adults and 50 lbs of ice - I was able to touch 5,600 rpm (38.7 mph). This is my typical load. Thoughts? Would you suggest a prop change? Thanks in advance.

 

[glacierbaze]

No

 

[Ky Grady]

Agree with glacierbaze. With that load and a 150,,, sounds like you are propped correct. You and half a tank, you should have no problem hitting 5800-6000 RPM, trimmed out correctly.

 

[Sdfish]

Thank guys! Appreciate the feedback!