Mr256 Posted May 16, 2012 Share Posted May 16, 2012 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? Quote Link to post Share on other sites
delaney Posted May 16, 2012 Share Posted May 16, 2012 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 Quote Link to post Share on other sites
Toddler Posted May 16, 2012 Share Posted May 16, 2012 Welcome to the group....... Thats sounds way out of wack......is the outdrive trim working properly?. Quote Link to post Share on other sites
Shepherd Posted May 16, 2012 Share Posted May 16, 2012 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. Quote Link to post Share on other sites
267Bob Posted May 16, 2012 Share Posted May 16, 2012 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. Quote Link to post Share on other sites
Chaparral Web Team Posted May 16, 2012 Share Posted May 16, 2012 Agree with the others, something is definitely out of whack. The 256 with the 8.1 should literally leap on plane. Quote Link to post Share on other sites
Hatchman Posted May 16, 2012 Share Posted May 16, 2012 Agree, that is whack. Run a compression check and change the spark plugs while at it. Quote Link to post Share on other sites
MonkeySeaII Posted May 16, 2012 Share Posted May 16, 2012 My 256 w/Merc 496 jumps on plane in about 4-5 seconds and tops out at 56-57 mph. You definitely have an issue going on. Quote Link to post Share on other sites
Mr256 Posted May 17, 2012 Author Share Posted May 17, 2012 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- Quote Link to post Share on other sites
MonkeySeaII Posted May 17, 2012 Share Posted May 17, 2012 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. Quote Link to post Share on other sites
Toddler Posted May 20, 2012 Share Posted May 20, 2012 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.. Quote Link to post Share on other sites
CPTRON Posted May 20, 2012 Share Posted May 20, 2012 agree with Toddler,came with 28's used 26's for toys etc,but now have tabs and no kids around and put 28's back on for better cruise/fuel..... Quote Link to post Share on other sites
Futzin' Posted May 21, 2012 Share Posted May 21, 2012 Those numbers do not add up to a prop issue. Typically, a sluggish hole shot prop results in a high top end (and vice versa).Get it checked out. Good luck! Quote Link to post Share on other sites
Wingnut Posted May 21, 2012 Share Posted May 21, 2012 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 Quote Link to post Share on other sites
Frank K Posted June 19, 2012 Share Posted June 19, 2012 My 07 SSI with V 8.1 will get up and go, so it sounds like all that you have been hearing from the others may be correct Quote Link to post Share on other sites
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