planing problem

[zack]

I have a '07 Crownline 220EX w 5.7 GI DP and when i put more than 6 people in the boat it struggles to plane out. Is this a prop issue or is thersomething wrong w my boat? Any advise would be appreciated.

 

[ne7800]

Re: planing problem

well i am no expert at this but how big are the people? and where are they sittin in the boat? mostly in the back? you might need to move them around

 

[zack]

Re: planing problem

i should have also mentioned that the DP is a stainless steel F4 which according to Volvo is the smallest pitched prop available for this engine. Is it safe to put on an F3 prop? When I had a full load of about 10 people I could only get the rpms to 2900. My dealer claims I should max out at about 4800-5000 rpms. I realize the large load would affect this, but 2000 rpms less seems like something else is wrong. The dealer cant find anything wrong and I am quite frustrated to think I will only be able boat with 4-5 people on my boat if i want it to plane out. thanks for all of your suggestions in advance!

 

[zack]

Re: planing problem

I had everybody in the bow and i still could only reach 2900 rpms

 

[zack]

Re: planing problem

do you think trim tabs are the answer?

 

[ne7800]

Re: planing problem

i would probably try trim tabs but like i said i an NO expert i'm sure someone with more knowlage about this than me will chime in soon

 

[rndn]

Re: planing problem

Your boat weighs in dry at 4400#. With additional weight for fuel, supplies and people I would guess that's all you're going to get with the 5.7 engine.

 

[zack]

Re: planing problem

i appreciate you trying to help! I bought the boat new last year and I just started noticing the problem this summer. I almost wonder if the elevation here in salt lake(4500 ft) is also playing a big role.

 

[zack]

Re: planing problem

My boat is heavy, but last summer I was able to get it up to 4400 rpms w 4 people in it. will the extra weight really have that much affect on the rpms?

 

[ne7800]

Re: planing problem

well i guess you need to think of it like this if you had a chevy truck with a 5.7 the truck would run good with three people but add 1000 lbs in the bed it would squat down and strugle a little

 

[zack]

Re: planing problem

would trim tabs or an F3 prop make a difference? the boat is rated to hold 10 people, but even 6 makes it struggle some.

 

[rrhodes]

Re: planing problem

What are your RPM's with a normal load? If you are not getting the correct WOT RPM's then a lower pitch will help a bit. Trim tabs will allow you to plane at lower speeds so yes they will help but unless you are getting on plane I can't really answer your loaded prop question.

 

[zack]

Re: planing problem

4400 rpms is at wot with a normal load. the problem is Volvo has a chart that says the F4 prop is the lowest pitched prop available for the 5.7GI. The F3 will fit, but is it safe since Volvo doesnt mention it as being an option for this engine?

 

[zack]

Re: planing problem

is losing 1500-2000 rpms normal with a heavier load?

 

[rrhodes]

Re: planing problem

I would say you are propped corectly however since you can't get on plane with a heavy load there is no way to tell what your loaded WOT RPM is. Think of it as you are pulling uphill and never reaching the top. I would think Tabs would allow you to plane loaded at a lower speed and then your Engine RPMs will increase as the stress on the engine is lightened,

 

[zack]

Re: planing problem

2900 rpm was my loaded wot at plane with 10 people in the boat, it just took me 10 minutes to get to plane with the help of the wind at my back. I was at about 7000 ft of elevation that day. I have also been able to plane out with a heavy load of 6 people at 8000 ft elevation and my wot was 3900 rpm. It changes quite a bit with only a few hundred lbs difference, thats why I almost wonder if there is some other underlying problem?

 

[steelespike]

Re: planing problem

I would think that at 4,500 ft you would need to rejete or calibrated for that altitude.
Should be a big help.If this is a new developement you may have a motor problem an 8 cylinder could have a dead cylinder and not be obvious except for poor performance. Is the throttle opening all the way?Bottom clean?Is it trimming in all the way? What is the pitch on a F4 and F3?If a F3 is less pitch and fits your setup it would help.It sure seems to me that setup could plane with 7 people.Trim tabe would help. But I think you have a motor problem.
We had a brand new outboard on here the other day with a dead cylinder.
Sometimes boats will absorb water sometimes in the flotation foam other5s in the fiberglass itself.Not likely on your new boat but you might weigh it and see what you get.

 

[zack]

Re: planing problem

it's really weird because the boat will pull a wakeboarder out of the water just fine, but then it will start losing power all of the sudden until the boat slows down enough and the wakeboarder sinks.

 

[rrhodes]

Re: planing problem

You very well may have a misfire, dead cylinder, or other issue. The fact that you could pull the wake board up and then you lost power leads me to agree with the others. Not a prop or tab issue.

 

[steelespike]

Re: planing problem

How is the engine temp?oil pressure?You could have a sparkplug failing under stress.