another Prop help thread

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Sdfish

GreatGrady Captain
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Model
Adventure
Hi all,

I have a GW Adventure 208 with a Yamaha F150 on it. Current prop is a 3 blade stainless steel 15 1/4 X 15, max RPM at full throttle is 5300 (this is with my boat fully loaded).

Any suggestions to get me more RPM, closer to 6000 at full throttle?

Thanks!
 
Hmmmm.... others with that boat can speak more intelligently than me (well, many, MANY people can!). But you're running a 15" pitch and are 700RPM shy. I guess this depends on what "loaded" means, but that doesn't seem right. You'd have to drop down too many inches. Are you basing that 5300 on totally WOT and also trimming up as much as possible before ventilation? It just doesn't seem right to start with - as if there's another issue. How's the compression?
 
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Hi Dennis - compression and engine are fine, low hours and runs great. just took a look at the picture I took and I did NOT have the engine trimmed up correctly, it was showing 1 bar. Looks like I'll have to go back out and retest!

Fully loaded, I had my boat loaded with 2 adults, full bait tank etc. As I would on a typical day of fishing.
 
best advice i can give is to call ken at prop gods.

beyond that, id call grady and see what they put on the boat with that motor. im guessing you will have to drop to a 13 pitch based on your current numbers, but that seems low
 
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I should note, that the current prop was from my previous 2 stroke motor. My dealer recommended a new prop and will suggest one, but i wanted to get opinions from the board as part of my research.
 
Sdfish said:
Hi Dennis - compression and engine are fine, low hours and runs great. just took a look at the picture I took and I did NOT have the engine trimmed up correctly, it was showing 1 bar. Looks like I'll have to go back out and retest!

Fully loaded, I had my boat loaded with 2 adults, full bait tank etc. As I would on a typical day of fishing.
Click to expand...
That sounds like a good plan - and that load is a good load to test with it (not "overloaded"). I suspect you're going to see those RPM's jump up quite a lot. Hey, there's worst things than having to go out for another boat ride! :)
 
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Attached below is the Grady White performance bulletin for a 208 Adventure with a single F150, in which they used a "14 1/2 X 15 Reliance SDS" prop for their test boat and got a top speed of 40.4 mph @ 6,000 rpm. I'd maybe start off with a prop more similar to those specs, though a quick call to Ken @ Prop Gods wouldn't hurt either.

208 Adventure performance test F-150.jpg
 
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Thinking you will gain 200-300 rpm just by trimming out. Do you have a hardtop, were you running with canvas, were you running with a full tank of fuel, clean hull?

On my 208 hardtop with F200, canvas up, full tank of fuel, normal load, fresh bottom paint I run 39-42mph at 5600-5800 trimmed fully out using a Powertech SCE4 4-blade 14x14p. Recommended by Ken at Prop Gods similar to the black Yamaha semi-cleaver design. Good all around performance, hole shot, reasonable low planing speed, holds when running Barnegat inlet. Not super responsive around the dock without giving a bit of gas. Had a 14.5x15p Solas HR4, tons of grip but overpropped. Mechanic at Marina tried 14.25x17 Reliance but said it didn’t do noticeably better than the SCE4 (that’s the factory-listed prop for an F200).

Am guessing that the 14.5x15 Reliance or the Powertech equivalent would with the F150, or even the SCE4. 4 blade I am using. The 14.25x15p is used on the bigger/heavier Adevture 215 with an F200.

I’d ask your mechanic what they would reccomend and also get Prop Gods input before buying.
 
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