Boat only planes out after shifting weight forward?

[jackmorgan]

Hi,

I'm new to boating. Just purchased a 2007 four winns vista 258 with the 5.7Gi penta engine. With 4 people on board (650lbs), full water, full fuel, and minimal gear the boat will not plane out without moving people forward in the boat. Basically, if I'm driving and 3 people are sitting in the back the boat just plows with the bow up. I tried playing with the trim and trim tabs to no avail. The boat just stays at 2800 rpm and won't go any faster. When i move two people towards the front of the boat the rpms gradually increase and then the boat planes. Is this normal for a boat of this size and engine? My friend who used to own a similar boat says it's normal, but I think i'm missing a lot of power. Any comments from someone with a similar sized boat / engine would be greatly appreciated.

Jack

 

[Scott Danforth]

are you trimming in all the way for your hole shot?

where are your trim tabs set?

 

[jackmorgan]

are you trimming in all the way for your hole shot?

where are your trim tabs set?

I have tried trimming all the way down (is this in?), tried trimming up a bit once the bow goes up, tried full trim tabs as well - nothing seems to work unless i ask people to move forward in the boat.

 

[mr 88]

Once you get up on plane what RPMs are you hitting ? The previous owner may have put on a overpitched prop thinking he would save on fuel. Most of the time a boat like that is running a 19" prop. If your over pitched it will take forever to get up on plane and never hit the specified RPM range, you just end up lugging the engine and actually burn more fuel.

 

[garbageguy]

I have tried trimming all the way down (is this in?), tried trimming up a bit once the bow goes up, tried full trim tabs as well - nothing seems to work unless i ask people to move forward in the boat.

By full trim tabs, do you mean all the way down? On my 25 ft Wellcraft with carb'd 5.7, it takes a bit more effort to get on plane with everyone astern, but just outdrive down all the way, don't needs tabs down all the way. Agree, check your prop to start

 

[oldjeep]

Either prop or your engine is just wore out. Did you have a compression check done when you bought it?

 

[Scott Danforth]

I have tried trimming all the way down (is this in?), tried trimming up a bit once the bow goes up, tried full trim tabs as well - nothing seems to work unless i ask people to move forward in the boat.

Your tabs should just be down a bit from horizontal. All the way down starts adding drag.

Regarding outdrive, yes, all the way in.

Assuming you have a single prop. Which ratio and prop are you running?

 

[boatman37]

i have a 1986 sea ray sundancer 250 with the 5.7. i have a 1.47 ratio outdrive with a 14.5x17 aluminum 3 blade prop. we had 6 of us (~1000lbs) on the other day with a full tank of fuel and about 10 gallons of fresh water. with 4 of us at the back of the boat and full tabs it took about 1/4 mile to get on plane. its a big boat for a 5.7 and full load.

FWIW i run full throttle at about 4000 RPM and about 33 MPH with 2 people on board so my prop is pretty close although i the next step in pitch would likely get me in max RPM range

 

[WIMUSKY]

What is the max range? Sounds like full tabs is not the way to go. They work like tabs on a airplane. I "think" they say 10deg on takeoff for a Cessna.... Maybe try 1/2 tab or even a little less...

 

[GA_Boater]

What were the results of this thread? Starting a new thread without referring to the old one means you will be getting the same suggestions again. :doh: http://forums.iboats.com/forum/engi...boat-will-not-plane-when-heavily-loaded/page2

 

[jackmorgan]

Once you get up on plane what RPMs are you hitting ? The previous owner may have put on a overpitched prop thinking he would save on fuel. Most of the time a boat like that is running a 19" prop. If your over pitched it will take forever to get up on plane and never hit the specified RPM range, you just end up lugging the engine and actually burn more fuel.

won't go past 4300rpm - should hit 4800. The prop is a stock stainless F4 so it's not the prop.

 

[jackmorgan]

What were the results of this thread? Starting a new thread without referring to the old one means you will be getting the same suggestions again. :doh: http://forums.iboats.com/forum/engi...boat-will-not-plane-when-heavily-loaded/page2

Was trying to get other opinions from people with similar boats to see if my issues are 'normal' and not an engine issue.

 

[jackmorgan]

Either prop or your engine is just wore out. Did you have a compression check done when you bought it?

Engine is 195psi on all cylinders (only has 70 hours) and prop is stock - perfect shape.

 

[Scott Danforth]

Isnt the F4 a duo prop designation?

if you have stainless F4 props, they were either added by the dealer or prior owner.

with duo props, your boat should shoot out of the water.

 

[jackmorgan]

Isnt the F4 a duo prop designation?

if you have stainless F4 props, they were either added by the dealer or prior owner.

with duo props, your boat should shoot out of the water.

Really? The person i bought it from said they were stock. It's a DPS-A drive (yes duoprop). They didn't come with stainless? Now i'm wondering if the props aren't in fact F4 as recommended by four winns (i have a box that says F4, but it looks like some spare aluminum props may have just been shipped in that box). I top out at 42MPH at 4300RPM ... Boat test logged 42MPH at 4800RPM in the same boat / engine. This would seem to me to indicate a more aggressive prop like an F5 or F6. Looks like i'm jumping in the lake to check!

 

[Scott Danforth]

look at the numbers on the prop to see what you have. however at 4300 RPM, I would say either your down a cylinder, or your over-propped.

FWIW, my pig of a boat would hit 46mph at 4600rpm with 6 people on board (or 4 people and 4 dogs) with the 5.7 and 290DP drive running B6 props, a full fuel tank, and 40# of ice and 6 cases of beer. hole-shot was about 50' long to be up and on plane. the B5 props would have a greater hole shot, however I had a lower top end.

 

[Chris1956]

A boat that large with a SBC is underpowered, IMHO. I have seen so many boats that large powered with a 305, which is considerably worse. "Everybody forward to get on plane and then back to their seats" is a standard operating principal, unfortunately.

A BBC would solve the issue. Anyone with a mid-20s cruiser, who can get a 454 V8 should seriously consider it, IMO.

The best the OP can do is tabs all the way down, and motor trimmed down to start. As plane is achieved, back off the tabs and trim the motor until optimum speed is achieved.

If plane cannot be achieved, a lesser pitch prop would need to be used.

 

[WIMUSKY]

Maybe you're not achieving WOT? Linkage adjustment?

 

[bruceb58]

A boat that large with a SBC is underpowered, IMHO. I have seen so many boats that large powered with a 305, which is considerably worse. "Everybody forward to get on plane and then back to their seats" is a standard operating principal, unfortunately.

A BBC would solve the issue. Anyone with a mid-20s cruiser, who can get a 454 V8 should seriously consider it, IMO.

The best the OP can do is tabs all the way down, and motor trimmed down to start. As plane is achieved, back off the tabs and trim the motor until optimum speed is achieved.

If plane cannot be achieved, a lesser pitch prop would need to be used.

Agree 100% with everything in this statement.

 

[redneck joe]

Waterlogged?