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What RPMspeed do you cruise your 454s at

R

rmm

Regular Contributor
"Curious at what RPM/speed oth

"Curious at what RPM/speed other people are running their 454s at your normal cruise? Boat type and size and if you know what kind of GPH are you seeing?

We typically run 3050rpm at around 21kts, 26gph, 31', around 14,000lbs, 1988 454s 1,100 hours, 18x22.5 props"
 
"We run 3400 RPM @ 18 knts, 28

"We run 3400 RPM @ 18 knts, 28 GPH, 36' ~22,500lbs, 1991 454s 950 hours, 19x16 props (3 blade Nibrals)"
 
"Cruisers 3380, 33-foot, displ

"Cruisers 3380, 33-foot, displacemt about 13,000 dry, props are 18x19 I think, running at about 3100, about 21 gph. Makes maybe 20 knots."
 
"35' Trojan 16,000 lbs 454

"35' Trojan 16,000 lbs 454XL xts. We run 32-3500 rpm and get 23-25mph. There is a thread with all of our numbers. It was a fuel saving thing. I think it depends a lot on trim, tide/current, wind, load, and engine tune. My best advice is run her till she sounds right and the speed feels right.
Capt. Kevin Z"
 
"That's called the "sw

"That's called the "sweet spot". Gotta be a mechanical person to "feel" it, however.

A note on boat weighs: The advertised hull weight (and we see them listed above) does not include full tanks (fuel, water and waste), all the junk we take along, or the people. For example. My 32 footer is listed at 10,500 bs. I'll bet it's closer to 14,000, and with no one aboard.

Jeff"
 
"For my 2 cents : 34 C Silver

"For my 2 cents : 34 C Silverton Carb 454's 18x 21.6 3 blade probably 15500...3200rpm 22kts about 20-24 gph...WOT currently 5000+..might be 4100 this spring
"
 
"Al .
Help me translate that

"Al .
Help me translate that RPM range. & do tell,,,why is that WOT RPM going to drop so drastically. Are you going to pull a couple of spark pug wires off?

Fred 156-M"
 
"No Fred.... I am desperate to

"No Fred.... I am desperate to locate a set of 4 blade props. If not...I have access to a set of well tuned larger props. When the boat was repowered, the previous owner used the original props which are a bit small ... I re-read the note weight is about 15000lbs, 3200 is about our normal cruise where in the right conditions we may hit 22 knots...Sorry for the lack of clarity Gee 15000 rpm would really be something"
 
"What year is your boat Al?
W

"What year is your boat Al?
What size shafts do you have?
It was 270 hp , 350's?

Fred 156-M"
 
"Fred...We run a 80% WELL rest

"Fred...We run a 80% WELL restored '80 34C which was 270hp/350. The 1 1/4 shafts have been replaced along with rebuilt drive line and bearings. The 454's cause a bit more squatting at speed but she does run well in all but those 6+ footer's and larger rollers in our man made sluice box called Barnegat inlet.

Propscan did make a remarkable change in our running performance and vibration. I believe this has to contribute to our total top end but it is still not enough prop since WOT can go to 5000. I diligently look for correct bore 4 blade props and the very few I find, still go for near new pricing. We launch in 35 days or so and I would like to get this part resolved. If you knew how much work there has been in 3 years between engines and electrical, you might question the sanity of it all ...but when we go out...I get sane again !"
 
"Yup, You are correct...They w

"Yup, You are correct...They were 350cuin and were repowered with the 454's a few years ago. The boat was not really maintained well but being a restoration nut... I figured we would try to bring it back...More work than I thought but she runs so so nice now. I was even thinking of bringing a portable crank up Victrola into the saloon but the needle arm would never track well enough in rolling waters. "
 
I didn't know that...a sma

I didn't know that...a small block in that boat doesn't do it any justice.

a gyro-stabilizing system will keep anything level. you could save a fortune and trade thte vinyl for them CD things my kids use or an MP3 thing...they don't seem to mind the motion
 
"Hey Mark,

Vinyl came out a

"Hey Mark,

Vinyl came out about 25 years LATER !..Some of these things are like bakelite and shatter as if a glass dropped on a ceramic floor... There is a certain charm though listening to Al Jolson and foxtrot music thru a wall of white noise and crackling ! I am too young to have experienced the originals but I do have a great appreciation for that era"
 
I used to have Elvis Presley s

I used to have Elvis Presley singing "All Shook Up" on Bakelite. No idea what happened to it. I think my brother sold it!!
 
"Thanks, again, for the educat

"Thanks, again, for the education...shows even us old dogs can learn a few tricks"
 
I paid $10 for "April Show

I paid $10 for "April Showers" in 1999...I would think Elvis is worth alot more...Call your brother
 
"I hear he's living in Ala

"I hear he's living in Alaska now, and it's so cold up there he's "All Shook Up!"

Jeff"
 
"My brother used to swap, buy,

"My brother used to swap, buy, sell records from under our noses all the time. It could be anywhere now if it even exists any more. He brought home Sandy Nelson playing "Teen Beat" I loved it and played it all the time, a few weeks later I was looking for it and he had already traded it without saying anything! I think he got Lonnie Donigans "My Old Man's a Dustman" for it!
This was all in the early sixties."
 
"Ah, the '60s!

I uplo

"Ah, the '60s!

I upload my old records and tapes to the hard drive of my PC, then burn them to CDs. My entire, 50 year's worth of records, tapes and regular CDs fit on 9 CDs in the mp3 format. Amazing.

Jeff"
 
"Hi, I am a new member. I stum

"Hi, I am a new member. I stumbled upon this site while trying to find out what kind of RPMs my 1989 454 (350hp) crusaders should be hitting at WOT. Boat is a 1989 41' Mainship convertible. I currently max out at around 2800-3000. I dont know the pitch of the props, they are 3 blade. Boat weighs 22000lbs dry. Love the boat but want to go faster!!!! Please help"
 
"Sounds to me like those engin

"Sounds to me like those engines are way overloaded. 454's should turn 4200-4400 RPM WOT. Do your engines backfire, or do they just not run any higher than 3000?

Sounds to me that the props are too large, and your lugging the engine (not good).

I'm sure others will chime in! Good luck!"
 
"what does the previous owner

"what does the previous owner say?

My dad over propped everything, he wasn't interested in fast.
His theory was, big reduction & swing as big a wheel as you can. He figured that 11-13 knots at 850 rpm was efficient as heck. & he was right, as long as your not in a hurry.

Fred 156-M"
 
"Oops thought I posted this ea

"Oops thought I posted this earlier, guess not. The engines run great. the boat gets out of the hole just fine I had even thought the tachs may be wrong but they both read the same. I am thinking now that maybe it could be a linkage problem. If I disconnect the throttle cable at the carb, should I set the linkage to whereever the carb linkage is maxed out?"
 
"THe throttle handles should b

"THe throttle handles should be wide open along with the carbs. Easy enough to check.

Jeff

PS: I've seen it where, do to wear or (??), this is nOT the case."
 
"Robert: PLEASE make sure tha

"Robert: PLEASE make sure that the carb throttle blades close when you bring the throttle levers back to the idle position <font size=""+1"">BEFORE</font> you restart the engines.

Fred 156-M"
 
"A bit of History maybe but de

"A bit of History maybe but definately not a science. Over the years, many prop repair houses, prior to the high tech industry of MRI readings, used to rate 80% of the RPM required for cruising. Don't ask me where this average came from but here's an example. If you throttle up to plane off the hull at it takes an RPM of say 4000 then 80% or 3200RPM whould equate to a reasonable crusing speed. Although this method was not a true science and would rarely be used today except boat owners in the Bayou of Louisianna, (LAUGH) it was somewhat a standard method in the days of large block long stroke gasoline carberated engines. We can chalk it up to a "Moment in Time" or "Heresay Gone Wild"."
 
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