Cruising RPM's?

[magicalbill]

Great thread magicalbill started,

I suppose I do not have to push my engine like the rest of you sea bearing sailors, but I like to cruise at 4000-4200RPM. I am frugal when it comes to fuel burn.

Thanks for you that said you will push the envelope to get rid of carbon.

A final thought on this, you mostly have Yammies, and I have a Honda. The Coast Guard use Honda's and pretty comfortable saying they push them hard at time and get 5000-6000 hours from the engines, so I think the new generation of engines have hiccups here and there, but they in general can take a beating for a long time.

Hey Lee; thanks, I was just curious for the most part.

My Grady Club had several 330's with F250's and they have to be spun above 4700 to run 30 MPH. That's underpowered to me, but it makes a strong case for long life even with hi RPM use, as many of those 250's clear 1000-1200 hrs and haven't even hiccupped.

As mentioned, I'm more conservative with my revs, and I just wanted to see what everyone else was doing.

Mr_mbuna has an interesting point, as I have 350's on my Marlin. Running them at 4300 keeps them out of flywheel degradation range. I usually can't run that setting as 4300 puts me at 39-40MPH and I seldom have a calm enough sea state for that speed. I also concur that above 4500, your really burning fuel. Above 5000 RPM I would suggest looking anywhere else but the fuel flow info.

Thanks again for all the input!

 

[leeccoll]

Yeah love threads like this where everyone is welcome and free to add their two cents.

Thanks for getting it started magicalbill!

 

[Fishtales]

4200-4600 depending on conditions.

 

[mr_mbuna]

I also concur that above 4500, your really burning fuel. Above 5000 RPM I would suggest looking anywhere else but the fuel flow info.

I can feel the money draining from my bank account at WOT. 5800 RPM = 33.3 GPH = $150/hour at current California marine gas prices. At least I'm moving 45 MPH (1.35 MPG).

At 4300 RPM I burn 14.3 GPH. That pushes my boat at 32 MPH, which works out to 2.2 MPG. Not bad for a 27' boat.

 

[SmokyMtnGrady]

Absolutely! You will find more issues from lack of use and boats that idle for long periods of time. Motors that didn't do proper break in and now "make oil". I will say I was a bit nervous on my first oil change on the new motor. lol

When I repowered in 17 with a 4.2 liter I followed the manual for the first 3 hours then ran it like I stole it. I got a lot of good advice here on breaking it in hard.So that's what I did and thus far no oil making .

 

[wahoo33417]

Well I'm gonna be near the low end again. Sweet spot for 2007 3.3L F250s pushing a 282 with poor bottom paint is around 3400-3500 rpm. Will open her up once in a while, but that only gets to about 5500 rpm and 45 mph - with a tail wind .

I mostly drift live bait, usually with a kite out (when its not frustrating the hell out of me). So I alternate between port, starboard and no engine running, just enough to replenish the drain from the livewell pump. Trying to minimize the hours at idle and total number of engine hours.

Rob

 

[magicalbill]

Well I'm gonna be near the low end again. Sweet spot for 2007 3.3L F250s pushing a 282 with poor bottom paint is around 3400-3500 rpm. Will open her up once in a while, but that only gets to about 5500 rpm and 45 mph - with a tail wind .

I mostly drift live bait, usually with a kite out (when its not frustrating the hell out of me). So I alternate between port, starboard and no engine running, just enough to replenish the drain from the livewell pump. Trying to minimize the hours at idle and total number of engine hours.

Rob

If you will re-read my original post, you'll see that you got an Honorable Mention...Hope all is well!

 

[mleads310]

I'm in the same boat as you wahoo, 2005 f250s , m19 props and I max out at 44-45mph with light load, fresh scrape/paint and tail wind. But I do cruise at between 3800-4200. For some reason my engines hummmm so beautifully in that range.

 

[dogdoc]

We were out offshore the other day and it was flat as a pancake on the return so I thought I would open her up and burn some carbon. 4900-5000 rpm, 39 mph and 40 gal per hour fuel burn. Boat ran great, but burned almost twice as much fuel per hour for that extra 10mph. I will stick with my 3800 rpm cruise.

 

[Uncle Joe]

Single 225 E Tec on a 24 Offshore.....I like to run at about 4100-4200. This usually gets me apx 27mph. All I need to get to my fishing areas. I do however....try to run for a few minutes at WOT on each return trip...I troll a lot and I feel this will burn out the accumulated carbon or whatever.

 

[Triton2300]

I run my 300 Zuke on average between 4500 to 5000. Redline is 6300 at full trim. What will kill an engine is excessive idling. I plan to decarbon this spring with a Sea foam shock. Dump a can of sea foam in with a gallon of gas, add oil if 2 cycle. start the engine and let it idle for 10 minutes. Shut it off and let it soak for a half hour. Start it back up and see if any carbon burns off. Repeat if necessary.

 

[PointedRose]

I run my 300 Zuke on average between 4500 to 5000. Redline is 6300 at full trim. What will kill an engine is excessive idling. I plan to decarbon this spring with a Sea foam shock. Dump a can of sea foam in with a gallon of gas, add oil if 2 cycle. start the engine and let it idle for 10 minutes. Shut it off and let it soak for a half hour. Start it back up and see if any carbon burns off. Repeat if necessary.

When you say ‘see if any carbon burns off’ what do you look for? When I’ve done seafoam before it exhausts white smoke.

 

[Triton2300]

Exactly. White smoke.

 

[Triton2300]

When I bought the Triton in 2019 it had an OX66 225 yam with 560 hours. The owner had a stack of maintenance receipts that would make you feel pretty confident. During the sea trial we opened her up and the best she would do is 5200 RPM. 14 1/2 by 15 pitch stainless wheel. I knew the engine was lugging but with 560 hours once I got the boat I could mess with it to get the RPM up.
We left Mystic Island New Jersey at 6 am and ran down the intercoastal to Atlantic City Inlet. In two hours we were looking at Wildwood, New Jersey. The engine seemed to like to run about 4500. I brought her in the Cape May Inlet to gas her before we headed over the Delaware Bay to Lewes. I charted the trip and we were right on 50 miles to Cape May. Took 53 gallons to fill it. Now I knew the engine was really working. I had to refill the oil reservoir in that it was almost empty.
We headed out the Cape May canal and pointed her towards Roosevelt Inlet, Lewes Delaware. She shut off about half way across. Would not even turn over. I pulled the cover and saw metal pieces everywhere. Cooked. Threw a rod right through the side of the block. Thank God for BoatUS. Four hours later he pulled us into the dock in Millsboro. 560 hours and that engine was toast. Improperly set up from day one. .
Repowered with a 300 Zuke a month later. I made sure the engine was installed at the correct height and propped correctly.
It will twist a 16x17 inch pitch stainless at 6250 trimmed up.
It’s equally important to have your engines set up properly to make them last. It really was a fun trip that day and one I will never forget!

 

[blindmullet]

I run my 300 Zuke on average between 4500 to 5000. Redline is 6300 at full trim. What will kill an engine is excessive idling. I plan to decarbon this spring with a Sea foam shock. Dump a can of sea foam in with a gallon of gas, add oil if 2 cycle. start the engine and let it idle for 10 minutes. Shut it off and let it soak for a half hour. Start it back up and see if any carbon burns off. Repeat if necessary.

On my little boat (115 Opti) you drain the fuel out of the pump/filter assembly and do a hot soak with the seafoam. That stuff is amazing! I always used it on my mustangs growing up but works much better on outboards. I could immediately tell the difference in throttle response the first time I did it. I need to service my Zuke next.

 

[magicalbill]

When I bought the Triton in 2019 it had an OX66 225 yam with 560 hours. The owner had a stack of maintenance receipts that would make you feel pretty confident. During the sea trial we opened her up and the best she would do is 5200 RPM. 14 1/2 by 15 pitch stainless wheel. I knew the engine was lugging but with 560 hours once I got the boat I could mess with it to get the RPM up.
We left Mystic Island New Jersey at 6 am and ran down the intercoastal to Atlantic City Inlet. In two hours we were looking at Wildwood, New Jersey. The engine seemed to like to run about 4500. I brought her in the Cape May Inlet to gas her before we headed over the Delaware Bay to Lewes. I charted the trip and we were right on 50 miles to Cape May. Took 53 gallons to fill it. Now I knew the engine was really working. I had to refill the oil reservoir in that it was almost empty.
We headed out the Cape May canal and pointed her towards Roosevelt Inlet, Lewes Delaware. She shut off about half way across. Would not even turn over. I pulled the cover and saw metal pieces everywhere. Cooked. Threw a rod right through the side of the block. Thank God for BoatUS. Four hours later he pulled us into the dock in Millsboro. 560 hours and that engine was toast. Improperly set up from day one. .
Repowered with a 300 Zuke a month later. I made sure the engine was installed at the correct height and propped correctly.
It will twist a 16x17 inch pitch stainless at 6250 trimmed up.
It’s equally important to have your engines set up properly to make them last. It really was a fun trip that day and one I will never forget!

A sad and interesting story in equal parts. This is educational and good stuff to know.,

 

[ItalianAngler]

Well I'm gonna be near the low end again. Sweet spot for 2007 3.3L F250s pushing a 282 with poor bottom paint is around 3400-3500 rpm. Will open her up once in a while, but that only gets to about 5500 rpm and 45 mph - with a tail wind .

I mostly drift live bait, usually with a kite out (when its not frustrating the hell out of me). So I alternate between port, starboard and no engine running, just enough to replenish the drain from the livewell pump. Trying to minimize the hours at idle and total number of engine hours.

Rob

Similar, my bottom paint is not the greatest, but it's lift kept so more of a cosmetic thing for me at this point. 2002 282 with F225's. 3700 RPM nets me around 29mph and 15gph. If I'm heavily laden I'll turn 38/3900 to keep to that cruise speed. If I'm really light i can trim it way out and get up to around 33mph and 4000 without hurting fuel economy. I do run her WOT when i get back in the river sometimes, it really does make a difference. There are times you can tell i haven't done it in a while, these engines like to run and run hard every so often. I have over 1800 hours on mine, they run regularly and get regular maintenance. tops.

 

[mleads310]

Italian, curious which props are you running?

 

[ItalianAngler]

Italian, curious which props are you running?

They are the ones they came with, 19 pitch. 15 1/4 diameter I believe, stamped with 19-M. 3 blade stainless. My only issue with them is that to avoid bow steer in a big following sea with any kind of angle i have to trim up to get the bow higher, but this causes cavitation. If anyone knows how to solve that problem I'd love to know. Aside from that wrinkle it's a great setup for my rig.

 

[wahoo33417]

If you will re-read my original post, you'll see that you got an Honorable Mention...Hope all is well!

Yup, I did catch that!