Boat Will Not Plane or Even Take Off!!

[Sundancer280]

Hello fellow boaters,

I have a 2005 Sundancer 280 with twin 4.7 Mercury Engines. I just encountered a very unusual problem and needed some help. My boat used to take off and plane within 30 seconds at around 3500 rpm, however, as of about a month ago this has stopped. When I floor the boat, it barely moves. If I'm idled, it runs fine. The lake was as smooth as glass yesterday and was pushing it full throttle and still looked like it was on 1000 RPMs, even though the reading was at 4000 RPM. The boat won't take off at all or plane, and was wondering if this something I could fix myself. Any thoughts on what could be the issue and how to fix it?

Note: The boat only had me and one other person on there, so it should've taken off. Also trim tabs were down.

 

[Woody]

Where do you boat? How long ago since the last time it planed off properly?

 

[Jeff Delbuono]

Trims down, drives tucked in ? Condition of bottom?

 

[Sundancer280]

Where do you boat? How long ago since the last time it planed off properly?

I boat in Lake Erie. The last time it planed off properly was about a month ago

 

[Sundancer280]

Trims down, drives tucked in ? Condition of bottom?

The trims were indeed down and the drives were tucked in. I'm unsure what the condition of the bottom of the boat was. This is the second year I've owned a boat and people are saying that algae gets built up and it may need a power wash. Do you think that's the case?

 

[Wanderer 290]

Coupler or spun prop hub? Tilt outdrives to trailer position, place in gear (assuming you have alphas) and see if the prop will turn in the opposite direction of the gear selection. It it is in forward rotate the crop in the reverse direction.

 

[Jeff Delbuono]

My boat jumps out of the water at the start of the season. If i dont use it for a week or 2 it starts to get sluggush. Im in salt water so its always fighting barnacle and scum. I will take to the shallows and scrub the bottom and scrape the drives.

This start: 4500 rpm planes at 10 sec and cruise at 3800 29 mph.

Aftet a 3 week no use: 4500 rpm planes at 30 sec and cruise at 4000 rpm 24 mph

Always clean the bottom before anything

 

[Wanderer 290]

The trims were indeed down and the drives were tucked in. I'm unsure what the condition of the bottom of the boat was. This is the second year I've owned a boat and people are saying that algae gets built up and it may need a power wash. Do you think that's the case?

I boat on Lake Michigan and while algae will slow a boat down I have never seen the growth keep is from planning. Not saying that it can or can’t just haven’t seen in 25+ years of fresh water boating.

 

[Sundancer280]

Coupler or spun prop hub? Tilt outdrives to trailer position, place in gear (assuming you have alphas) and see if the prop will turn in the opposite direction of the gear selection. It it is in forward rotate the crop in the reverse direction.

I had a mechanic take a look at the engine coupler and spun prop and he said that they were fine. That's where I got completely thrown off too

 

[Sundancer280]

I boat on Lake Michigan and while algae will slow a boat down I have never seen the growth keep is from planning. Not saying that it can or can’t just haven’t seen in 25+ years of fresh water boating.

Okay I will wash the bottom and see where I can go from there

 

[Sundancer280]

My boat jumps out of the water at the start of the season. If i dont use it for a week or 2 it starts to get sluggush. Im in salt water so its always fighting barnacle and scum. I will take to the shallows and scrub the bottom and scrape the drives.

This start: 4500 rpm planes at 10 sec and cruise at 3800 29 mph.

Aftet a 3 week no use: 4500 rpm planes at 30 sec and cruise at 4000 rpm 24 mph

Always clean the bottom before anything

Perfect. I'll go ahead and get it lifted so I can wash the bottom, and then I'll keep you posted so you know what's going on and how things went!

 

[Tim Fila]

I can almost guarantee its algae on the bottom

 

[Jeff Delbuono]

I can tell ya. In nj all boats fight this problem through the season. If i am in the water enjoying the day. The first thing i do is scrub the waterline, clean the bottom and scrape the drives. You will see the difference. My friends laugh at me tho, i put on a life jacket, snorckel, tie a rope to me and go to work. Takes about 15 minutes but well worth it and no need to take boat out. On any given day you will see other boaters doing the same

 

[Espos4]

Hello fellow boaters,

I have a 2005 Sundancer 280 with twin 4.7 Mercury Engines. I just encountered a very unusual problem and needed some help. My boat used to take off and plane within 30 seconds at around 3500 rpm, however, as of about a month ago this has stopped. When I floor the boat, it barely moves. If I'm idled, it runs fine. The lake was as smooth as glass yesterday and was pushing it full throttle and still looked like it was on 1000 RPMs, even though the reading was at 4000 RPM. The boat won't take off at all or plane, and was wondering if this something I could fix myself. Any thoughts on what could be the issue and how to fix it?

Note: The boat only had me and one other person on there, so it should've taken off. Also trim tabs were down.

Ok, if you want good replies, we need good correct info.
First, which engines do you have? There is no 4.7 mercury engine. It’s 4.3 V6’s or 5.7 V8’s.

Which outdrives do you have?

What do you mean by the 1000 rpms and 4000 rpms statement?

Was one motor at 1000 rpm and the other was at 4000 rpm?

Excessive bottom growth usually has both healthy motors at around the same max rpm.

If one motor was at 1000 rpm and the other was at 4000, you’ve probably got an issue with the 1000 rpm motor. It’s not pulling its weight and dragging the other motor down, not allowing the boat to plane.

Clarify your original post, update your profile info, and you’ll be on your way to getting good feedback on your issue.

 

[Fill Ess]

I considered getting a remora solo to combat this until I saw the price

 

[Jeff Delbuono]

Didnt know what that was so i looked it up. HOLY SHIT $1,900. ill stick with my dollar store scrub pads and harbor freight scraper. But very cool tool and had no idea that made something like that

 

[dwna1a]

Let us know what you find under the boat.

Do both engines run off one fuel tank?

If one is at a 1000rpm and the other is at 4000. It’s a motor issue. Without better info I’m guessing ICM. It controls the timing advance, once it starts to fail the motor won’t go past the rpm that it controls.

 

[Fill Ess]

I'm having a similar issue at the moment so I would also look at the bottom. Salt water only, kept in a slip since May. Both 5.0 engines run great and will rev to at least 4k in neutral. I haven't been on plane for several weeks because either we're taking people out on a slow cruise, with kids in the cabin, usually 1600 rpm -- or I'm out solo in the morning doing the same. Above 2000 rpm the fuel burn is way up along with the wake. For whatever reason, I just didn't see the need to get on plane. The boat doesn't just sit around, I take it out 3-4 times per week. New bottom paint before the season started. The other day, realizing the bottom growth has been building up, I decided to go out and get on plane. Sure enough, max at WOT is about 3200 rpm on both engines and won't get on plane with the drives and tabs down. It could get on plane fine at the start of the season. Other than cleaning the drives and tabs from the back, I should have been keeping up with the bottom and now I'll probably do a quick haul and power wash to enjoy the rest of the season .... or I'm stuck doing the slow cruise

 

[Espos4]

I'm having a similar issue at the moment so I would also look at the bottom. Salt water only, kept in a slip since May. Both 5.0 engines run great and will rev to at least 4k in neutral. I haven't been on plane for several weeks because either we're taking people out on a slow cruise, with kids in the cabin, usually 1600 rpm -- or I'm out solo in the morning doing the same. Above 2000 rpm the fuel burn is way up along with the wake. For whatever reason, I just didn't see the need to get on plane. The boat doesn't just sit around, I take it out 3-4 times per week. New bottom paint before the season started. The other day, realizing the bottom growth has been building up, I decided to go out and get on plane. Sure enough, max at WOT is about 3200 rpm on both engines and won't get on plane with the drives and tabs down. It could get on plane fine at the start of the season. Other than cleaning the drives and tabs from the back, I should have been keeping up with the bottom and now I'll probably do a quick haul and power wash to enjoy the rest of the season .... or I'm stuck doing the slow cruise

That boat should jump out of the water with twin 5.0’s and just you on board. Definitely go for the short haul and power wash or hire a diver to clean the bottom.

Hope you can enjoy the rest of the season.

 

[Stee6043]

Another Great Lakes boater here. I think some of you guys may overestimate how much stuff we get on the bottom of our boats up here in Gods country

I doubt you'd get enough growth on Lake Erie in a month of sitting still to keep a boat from planing. Slow it down a bit, sure, but not stop it from planing entirely. I'm casting my vote for "something else is going on here".