Boat will not plane when heavily loaded

[jackmorgan]

Hi,

I have a 2007 four winns vista 258 with a 5.7 Gi volvo penta. When i first put the boat in the water it wouldn't plane out - it bogged and wouldn't go above 2800 rpm - this was with 5 adults on board. I ended up replacing the fuel pump module and went out with two adults on board and it still bogged at 2800, but rpm gradually increased and it eventually got up to plane. From this point forward, there would always be a delay at about 2800 rpm but the rpms would build and once planed out the rpm would reach WOT (4300 rpm - which may be too low for this engine?) I tried to go out yesterday with 5 adults, full water, fuel and some gear and it again bogged at 2800 and wouldn't go on to plane. Is this normal for a boat of this size? Do i have an engine problem? (should the rpm increase smoothly, or will it not go above 2800 until it reaches plane?).

Thank you.

Jack

 

[mklearl]

Are you running with the drive in the full down position?

 

[jackmorgan]

Are you running with the drive in the full down position?

Yes.

 

[mklearl]

Trim up. I can get 3600 rpms at full throttle full down. When you bump the trim up you will hear the rpms increase.... small increments at a time. Just a bump up. Watch the bow. When the bow starts to go up and down or "porpoise" then bump the trim back down until it stops. You should have full rpms. If not, you have a mechanical issue. Google search how to properly trim a boat.

 

[mklearl]

If that doesnt work then check out this awesome checklist... post number 3.

http://forums.iboats.com/forum/engi...drives/570800-1991-4-3-not-reaching-wot-rpm-s

 

[jackmorgan]

Trim up. I can get 3600 rpms at full throttle full down. When you bump the trim up you will hear the rpms increase.... small increments at a time. Just a bump up. Watch the bow. When the bow starts to go up and down or "porpoise" then bump the trim back down until it stops. You should have full rpms. If not, you have a mechanical issue. Google search how to properly trim a boat.

Ok, so my bow is pointed straight up at 2800 rpm. You're saying if i trim up when the bow is all the way up it will help the boat plane out? I thought it would do the opposite and keep the bow high. When I have lighter loads it planes out with no trim adjustment at all - i trim it up a bit after it's on plane.

 

[jackmorgan]

If that doesnt work then check out this awesome checklist... post number 3.

http://forums.iboats.com/forum/engi...drives/570800-1991-4-3-not-reaching-wot-rpm-s

Thanks for the checklist .... I've actually checked all of these items and everything is perfect. The only thing i have left is cleaning the injectors (there may be some clogging from the old fuel cell paint), changing the plugs, wires, cap, and rotor. The engine only has 70 hours on it. Anything else i should try?

 

[mklearl]

Wrong props, boat not properly loaded. Try trimming up. Getting on plane does not mean the boat is as flat as possible. The bow will be up when trimmed properly and you will be puting less of a load on the engine giving you the rpms you are missing. Less boat in the water means more speed and efficiency. Bow up and props pushing forward, not angled up and down. Finding that sweet spot is an art forms but easily obtained once you get the hang of it.
Like I said try trimming first before you go out and buy new props or sink any more unnecessary money into it. Google how to properly trim a boat. Boatus put out a decent YouTube video. Goodluck.

 

[Thalasso]

You need to move some weight forward to get it to plane easier. Tabs down trim down. When it comes on plane then you can move the weight wherever

 

[mklearl]

Thanks for the checklist .... I've actually checked all of these items and everything is perfect. The only thing i have left is cleaning the injectors (there may be some clogging from the old fuel cell paint), changing the plugs, wires, cap, and rotor. The engine only has 70 hours on it. Anything else i should try?

So is this a new issue or has the boat always run like this?

 

[jackmorgan]

So is this a new issue or has the boat always run like this?

I just bought it about a month ago. the previous owner said it ran fine, but he only putted around.

 

[jackmorgan]

just a note - the engine maxes out at 4200 rpm (when it gets on plane with lighter load). Manual states it should hit 4600-4800. The props are original stainless.

 

[mklearl]

just a note - the engine maxes out at 4200 rpm (when it gets on plane with lighter load). Manual states it should hit 4600-4800. The props are original stainless.

What do you mean when it gets on plane? Are you trimming up at that point?

 

[jackmorgan]

What do you mean when it gets on plane? Are you trimming up at that point?

the Engine will not go above 2800 until it gets on plane. If it's too heavy it won't go on plane and thus won't go above 2800 rpm. I have tried trimming up when on plane at WOT and do so until the boat starts porpoising, then go down a touch. this yields 4200 max rpm.

I'd like to thank everyone for the responses while i try to track down this issue.

 

[mklearl]

Ok. There is a big difference between bogging down at 2800 rpm and getting on plane and missing 600 rpm. I would go through the checklist again but I honestly think if you are properly trimming and only missing 600 rpm I would guess a different prop.

 

[larson260]

If you are able to, check your prop set , should be F-4

 

[Jason89sunbird]

That's a big heavy boat. This guy has a 248 vista and says his is a 5.0 GI 270hp, I'm sure he is empty and by himself but who knows. https://www.youtube.com/watch?v=7NDrcnrqh7Q here is a 258 but not a speed test https://www.youtube.com/watch?v=El8DoMM9754 I would want a 8.1 for that big of a boat, but that's me. My 5.0 GL took about 14 secs to plane with a 18" 4 blade. I have now made it to a 6 sec plane with a 21" 4 blade, a lot of tweaking. At the same time if i weigh the boat down to 6 people I'm not a happy captain again, I just bought a 350 block for the low end grunt.

 

[larson260]

JackMorgam: Please verify its a 5.7 Gi. What drive do you have. If its a DPS duo prop with F4 prop set you should'nt have a problem getting on plane and should see 4600-4800 wot with a light load.

 

[jackmorgan]

No Title

I thought this engine had a direct ignition coil, but turns out it just looks like one - it has the traditional cap and rotor. I took it off and found severe corrosion (pic attached). Could this be causing a lack of power? I have one on order anyway.

 

[jackmorgan]

JackMorgam: Please verify its a 5.7 Gi. What drive do you have. If its a DPS duo prop with F4 prop set you should'nt have a problem getting on plane and should see 4600-4800 wot with a light load.

Yes, it's a 5.7 Gi-G, DPS Duo prop with F4. thinking it's a spark issue as mentioned in my previous post.