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Hey boaters, I purchased a 2006 256ssi with the Volvo 8.1 375hp - f5 duo prop. The boat is a dog out of the hole, plows forever. Top end can hit 45mph (speedo) at 4400rpm. The motor seems to be running strong. Anyone else experience this?

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IMO, both hole shot and top end sound out of whack. if you don't have a improper prop and a merc outdrive change the eccentric bushing on the trim cylinders (rotate 180 degrees) this will lower your drive another 2" or so and drastically improve your planing time. takes about 15 min. I'll guess that your top end should be closer to the 50mph or greater from others on this site. if you don't have trim tabs consider that as a project all are happy with the results from that investment

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Sounds to me like you're down a cylinder. I'd replace the spark plugs...big block MPI power can mask an engine being down a cylinder, and you don't want to have a cylinder washed out from fuel. Bad mojo for the wallet.

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Hey boaters, I purchased a 2006 256ssi with the Volvo 8.1 375hp - f5 duo prop. The boat is a dog out of the hole, plows forever. Top end can hit 45mph (speedo) at 4400rpm. The motor seems to be running strong. Anyone else experience this?

As others have suggested there is definitely something wrong with your boat. I have essentially the same setup with the 400HP Volvo 8.1 and my boat is a rocket out of the hole. I don't know what the top end is yet since it is still in the 2 hr break in period but I test drove a 2007 256 SSX with a 375 HP Mercruiser and we got it up to 54 mph without burying the throttle.

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Thanks for the suggestions. Monkeyseall or Toddler, what prop are you guys running? The plugs are a simple start and trim seems to be lowering correctly (need to look into that adjustment). The Chaparral dealer suggested possibly replacing the prop with a f4 or even a f3. I'd like to know that is the fix prior to dropping the coin. Its not uncommon for us to have six adulst and a few kids when we're out. Appreciate the help-

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I have a Merc but I have 28" Pitch stnd prop set. Even with 6 adults and 2 kids, my boat still jumps on plane. Your RPM should be more like 4800 at WOT too. I don't really think you have a prop issue, it sounds more like you're down a cylinder or something. That adjustment to the bushing only applies to the Merc Bravo III, not sure if the Volvo has the same thing.

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Thanks for the suggestions. Monkeyseall or Toddler, what prop are you guys running? The plugs are a simple start and trim seems to be lowering correctly (need to look into that adjustment). The Chaparral dealer suggested possibly replacing the prop with a f4 or even a f3. I'd like to know that is the fix prior to dropping the coin. Its not uncommon for us to have six adulst and a few kids when we're out. Appreciate the help-

Boat came with 28p set, Picked up a 26p set for an extra set. I like the 26's better they seem to better a slower speeds. But they also put the engine up to the rev limiter at WOT.

.

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Thanks for the suggestions. Monkeyseall or Toddler, what prop are you guys running? The plugs are a simple start and trim seems to be lowering correctly (need to look into that adjustment). The Chaparral dealer suggested possibly replacing the prop with a f4 or even a f3. I'd like to know that is the fix prior to dropping the coin. Its not uncommon for us to have six adulst and a few kids when we're out. Appreciate the help-

Try not to compare Merc and Volvo prop selection as the final drive ratio's are different. The Volvo's do not use the eccentric trailing end trim cylinder bushing either so no adjustment there. Just make sure the drive is going down all the way. I'm with Shep, sound like you are down a cylinder. When you pull the plugs, compare them closely for signs of over fueling on a single cylinder.

W

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