2007 Sundancer 260 - got fuel, no plane

V

Vladio

New Member
May 15, 2023
15
Boat Info
2007 Sundancer 260
Engines
Merc 350
Two of my boys came down to the bay on Saturday so we took the boat out - 4 ppl total. I had worked on the fresh water tank earlier that day and had it about half full, the black water tank was going to be pumped out when we got back... was a little over half full. We took on 40 gallons on top of the tank being around a quarter - around 60 gallons total after fueling. Once back in the channel we couldn't get on plane - around 10kts was max. I emptied the fresh water at Hart-Miller and on the way back we were getting 14 kts at WOT. The engine seemed bogged down at wot, I didn't see any misfiring, smoke or any signs of issues.

Would I of got a code if it was an engine issue? Mercury 350 mag with 2 counter rotating 24p

I just got the boat, had the engine rebuilt as part of the deal. The rebuilder is a speed-boat shop, the owner test drove the boat before we picked it up. The first thing he said to me is I might want to have the props checked, "it seems like they're too steep".
 
Personally if it would me I would take it right back to the first and you picked it up from and have him go on aride with you. That doesn't seem right at all
 
Just out of curiosity what was your wide open throttle RPM
 
I would ask the mechanic who rebuilt the engine if he test drove the boat it could be timing it could be anything but that boat should go well well over that mile an hour
 
On the way back from picking it up the Idle Air Valve went out, it gave a fault and beeped. If it was an engine issue should I of got a fault as well?
 
Yeah I would thought that you would have got an alarm or something would have came up on smartcraft a code
 
I'm 90% sure we were on plane for a short period before fuel too.

I will say this boat is a dog out of the hole. Father's day we had all of us (5) out and it was slow getting up on plane.
 
Ok let’s back up. You bot the boat needing an engine rebuild. The engine was rebuilt and mechanic tested and said all was ok, except maybe the prop. You had it out on Father’s Day and it ran ok, except slow to get on plane? Just trying to figure out if the rebuilt engine ever worked properly.
 
Golfman25 said:
Ok let’s back up. You bot the boat needing an engine rebuild. The engine was rebuilt and mechanic tested and said all was ok, except maybe the prop. You had it out on Father’s Day and it ran ok, except slow to get on plane? Just trying to figure out if the rebuilt engine ever worked properly.
Click to expand...

Ran fine since replacing the IAC valve the first weekend I had it (6/2/23 weekend). Took it from Middle River, MD to Kent Narrows the week of July 4th, had 3-4 hours of running with no problems going from the west shore to the east and back. We had a graduation last weekend (7/15/23) and didn't go to the boat.
 
Scott215 said:
Yeah I would thought that you would have got an alarm or something would have came up on smartcraft a code
Click to expand...
Codes aren’t always set.
Low compression…. No codes
Fuel pressure or volume issue……no codes.
 
Sure you didnt accidentally hit something when you changed the IAC motor
 
So it was working fine as of July 4. What has changed since then?

Check the fuel. Maybe you got some bad stuff.
Make sure all the plug wires are securely seated and go to the right plugs.
Maybe check the fuel pump? Is it new or did they reuse the old one?
 
Was the change the two extra people on the boat? Your mechanic mentioned the boat might be over-propped. Odds are he came to that conclusion either based on experience with your set up, or he ran the boat (likely alone) and found it to be sluggish getting on plane.

There may be nothing wrong other than the prop. That is a big heavy boat for a single small block V-8 and four adult passengers. The correct prop will be absolutely vital for that motor to get the boat on plane.

Also, check to make sure the celery stick is located in the slot to achieve maximum trim. That can help considerably.
 
keokie said:
Was the change the two extra people on the boat? Your mechanic mentioned the boat might be over-propped. Odds are he came to that conclusion either based on experience with your set up, or he ran the boat (likely alone) and found it to be sluggish getting on plane.

There may be nothing wrong other than the prop. That is a big heavy boat for a single small block V-8 and four adult passengers. The correct prop will be absolutely vital for that motor to get the boat on plane.

Also, check to make sure the celery stick is located in the slot to achieve maximum trim. That can help considerably.
Click to expand...

We're going down tomorrow evening. We'll take it out first thing Friday for a quick run.

I have to check the weight limit. We had 600+ lbs of humans, 60-65 gallons of fuel, 2/3 black water tank and 10-15 gallons of fresh water. I didn't think about it at the time but the bilge had a good bit more water from flushing the fresh water tank. We followed through on the pump-out as planned when we got back and the bilge and fresh water tank are now empty.

Things went south after getting fuel. Exiting the 6 kt zone I'm pretty sure we got up on plane. A rope came loose so I came off quickly, retied the rope then motored slow to the fuel dock where we took on 40 gallons on top of 20-25 we already had. The guy that told me about the prop races boats, that's all he does and has been doing all his life. I have a lot of confidence in what he says, that was the first thing he said when we pick up the boat. He suggested a place that will scan the prop and let me know if somethings not right. My intention was to do this in the off-season if possible.
 
Quick update incase anyone else with a 260, 350 mag has this issue... it was the fuel pump. Apparently, there was something inside the Cool Fuel unit that was painted. The paint flakes off and clogs everything downstream, injectors were either clogged to stuck open. I took it to a Merc service marina, they diagnosed the issue. Mercury is warrantying everything, I have to pay labor, but, the parts took since July to come in... taking it this weekend to have it fixed.
 
I can also tell you you’re probably overpropped on those 24s unless you have the high altitude package with 2.42 to one gears . I have the 6.2 with 2.2 to 1 gears and I just had my factory 20s de-pitched to 19 inches to get back to that 4850 wide-open throttle minimum. My boat is a little bit heavier than most as it has the generator and the arch option.
 
You must log in or register to reply here.

Forum statistics

Threads
113,253
Messages
1,429,311
Members
61,128
Latest member
greenworld
Back
Top