260da 6.2l river run

Yea but at 3000 I'm pretty much plowing. My 260 runs best around 4000. I just had a few people tell me that running at that rpm for extended times would be hard on the motor. Outside of normal wear and tear would I be (for lack of a better term) beating my boat?
 
keets said:
Yea but at 3000 I'm pretty much plowing. My 260 runs best around 4000. I just had a few people tell me that running at that rpm for extended times would be hard on the motor. Outside of normal wear and tear would I be (for lack of a better term) beating my boat?
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What is your speed around 34-3500RPM.
I know your boat is heavier than mine, but your 6.2 is more powerful. I cruise at 34-3500RPM and 25.7 knots. 4000 for that length of time certainly will be more wear than desired.

4000RPMS is:
500RPM X 60Minutes x 12 hours= 360,000 RPM
more than 3500RPMS
 
my boat wants to fall off plane around 3,500. Not sure of speed tho. So I guess what your saying is to run the rpms up just high enough to stay up. I understand your math, however running at 3500 rpms would take me longer to get to my destination so that would increase the overall rpms also. Well my speed will vary anyway timing the locks. Sometimes I will have to run wide open to get to an open lock and other times I will have to slow down waiting for a lock. This summer may be the perfect time for a long river run. just don't want to destroy my motor doing it.
 
keets said:
my boat wants to fall off plane around 3,500. Not sure of speed tho. So I guess what your saying is to run the rpms up just high enough to stay up. I understand your math, however running at 3500 rpms would take me longer to get to my destination so that would increase the overall rpms also. Well my speed will vary anyway timing the locks. Sometimes I will have to run wide open to get to an open lock and other times I will have to slow down waiting for a lock. This summer may be the perfect time for a long river run. just don't want to destroy my motor doing it.
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my boat wants to fall off plane around 3,500.
I'm very surprised at that number. Is it propped correctly?

however running at 3500 rpms would take me longer to get to my destination so that would increase the overall rpms also.
The RPM's will stay the same, the amount of revolutions will increase but at a much less stressful level
 
dpvandy01 said:
.........The RPM's will stay the same, the amount of revolutions will increase but at a much less stressful level
Click to expand...
This is the point right there. A constant run at 4000RPMS is pretty high for that long of a duration.
 
You didn't say what river? You could update your signature so we don't have to ask.

I'm planning a trip on the Ohio next summer in my 180. Apples and Oranges, but it likes 2700 to stay on plane and 3000 is a nice setting to get somewhere with a nice attitude, adequate speed and low noise/vibration.

My Silverton likes 3300 RPM and up for planing, so I try to stay closer to 3300 for less noise and wear.
 
I would suggest running your boat in the 3600 to 3700 RPM's range. I have the same motors in my 320 Dancer. Ideally you want to run your boat at 75% of WOT or less. I run my 350 Mag's around 3600 RPM's most of the time. My 260 with a Big Block - liked to run around 3300 RPM's. 4000 is a bit much in my mind.
 
Ok updated my signature. Ohio river. Yea, once I go under 3,500 rpms the boat starts to fall off plane. I like to run 3,700 to 4,000 just feels right. I run with my tabs all the way up. just use one or other to balance boat. My wot is 5,200
 
keets said:
Ok updated my signature. Ohio river. Yea, once I go under 3,500 rpms the boat starts to fall off plane. I like to run 3,700 to 4,000 just feels right. I run with my tabs all the way up. just use one or other to balance boat. My wot is 5,200
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You need to prop up then. If you are @ 5200 at WOT you're way to high. There is your problem. What is your props pitch? What Drive do you have?

If 24" you need 26". You may even have 22" The higher prop pitch will lower your RPM and allow you to cruise at a more reasonable RPM.

Usually a 2" prop uptick will lower your RPM 200 or so.
 
Todd is right, check your diameter too. You could have a combination of things limiting your speed. I think your WOT should be closer to 4800 right? That would suggest a 4 inch pitch change. What drive are you running and what year is the boat? Did I miss that somewhere?
 
Keets,

3 years ago I ran a new 2005 260 DA from Charleston to Beaufort which is about 140 miles round trip. This one had a 350 MAG B-III with a generator. Here's what I noticed, 3,600 rpm was required to maintain somewhat of a clean plane, 3,800 rpm felt better and 4,000 rpm felt best. WOT was 5,200 rpm. This was with just two people on board with minmimal gear. For what it's worth we generally ran around the 3,800 rpm mark. Check your owner's manual and I think you will find that wide open throttle is 4,800-5,200 rpm. This is also the WOT for newer 350 mags.

On a different note, if you go up a couple of inches in pitch with a B-III, I think you will find that you will lose something 300-400 rpm. Your holeshot will suffer as well.
 
The 350Mag/6.2MPI are both 5200 RPM's WOT. So he is propped correctly.

Fast Facts Propshaft HP 320-hp
Configuration V8
Displacement 6.2 L / 377 CID
Bore & Stroke 4.00 x 3.75
Fuel System Multi-Point Electronic Fuel Injection
Base Engine Weight 933 lbs.
Length/Width/Height 32 x 30 x 22
Max RPM@WOT 4800-5200
Warranty 3-year
 
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Thanks for the info. Learning alot. I was able to get her up on plane with 8 good sized adults and loaded with supplies, took a little extra time tho. I learned how to best use the tabs for my 260da on this site. Great bunch of people here.
 
skolbe said:
The 350Mag/6.2MPI are both 5200 RPM's WOT. So he is propped correctly.

Fast Facts Propshaft HP 320-hp
Configuration V8
Displacement 6.2 L / 377 CID
Bore & Stroke 4.00 x 3.75
Fuel System Multi-Point Electronic Fuel Injection
Base Engine Weight 933 lbs.
Length/Width/Height 32 x 30 x 22
Max RPM@WOT 4800-5200
Warranty 3-year
Click to expand...

I knew the 350Mag's had a 5200 WOT, but I didn't know that about the 6.2s'. If that's the case I retract my statement. But, for what it's worth, I still think for that long of a day/run you'll be kinder to your engine to run at lower RPMs
 
Keets - How much is your drive trimmed out at 4,000? The more your drive is trimmed out, the more difficult it will be to maintain on plane as you reduce your rpm.

Oh yeah...what's the hurry man? You know river travel is hurry up and wait! It is always funny when I leave a lock the go fast crowd goes like a bat outa hell, and then I catch up with them waiting for the lock 90 minutes later....waiting for a tow to lock through for the next 2 hours.
 
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Well not so much in a hurry, I like how it feels running at 3,900 to 4,000 rpms. I was just wondering if that was going to beat the boat over a 12 hour run back to back days. When we all go up river to pittsburgh, we fill up the locks, if I'm one of the first out of the lock I do run fast and hard. Alot of boats come out at the same time and most are bigger than me and they take off so if your in front it's better to stay in front. If I come out in the back of the pack I just lay back and take my time.
 
Don't want hijack the thread but what is the difference between the 6.2MPI and 350MAG???
 
Green balls for SeaRide! Oh wait, we don't do that anymore. lol

I have a 240da with a 5.0 w/BIII, and I run 3800 to 4000 rpm as my comfort zone for hours at a time on my run to the Bahamas every year. To me the boat feels right at that rpm. Yes I can stay on plane down to 2800 rpm, but I'm in a hurry! (I kid) I talked to the merc tech and he tells me the newer motors can handle thoes revs because the motors are built to tighter tollerances.? I don't have anything to back his statement up, but you have to trust someone.? GPH at that rpm runs between 10-12 gph, depending on wind and waves.
 
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