cruise RPM

[zelatore]

Just wondering, what RPM do you normally cruise a 502 at? Most of the BB gas motors I deal with are in heavier applications, and I ususally recomend a cruise of 3500. I've found I like to run my 22 at 4000, which puts me a little under 60 mph on the GPS depending on conditions and trim. It does seem a little high, but I don't have much experience with a light boat/stern drive to judge against.

Any thoughts?

[fegettes]

I usually cruise at 3,000, or a little above that, some times as much as 3,500. And on occasions, I may run WOT a short distance just to see how the boat performs. This is how I run my Blackhawk and Sport.

Steve

[Dr. Dan]

:smash:When we were running South on Lake George... this year we had a Squadron of a half a dozen or so boats... just running... this was not during the Poker Run.... we were cruising about 60 also. I guess it's all relative to water conditions and the group you are boating with...

I think running 45 to 60 mph for distance travel in a 22 Classic is a very comfortable range.... now when I had my smaller motor... the 60 would have been pretty close to WOT for me so again it's relative.

I can also cruise at 70 or 75 now... but to "Cruise" kinda implies a "Prima Face' Speed"...(not clear on the spelling...) so whatever the conditions & circumstances allow for a safe speed & operation of the Boat under those general conditions.

Glad you're getting some time on the water... nice pics... your 22 makes a great looking Dinghy against those big boys.:wink:

Doc :bonk:

[Barry Eller]

Here is a Powerboat Magazine test on a 22C with the HP500. There is a PDF file at the bottom on the page that shows MPG at given RPM'S. If cruising for fuel economy, the test results showed 3.2 MPG @ 2500 RPMS. The test also shows speed at given RPM'S, 2500 =34 MPH. I know several of us with 502's run faster than their test results show in this report. My motto; "When in Doubt, Trim it Out"!


http://www.powerboatmagazine.com/2002tests/jan1.php

[Carl C]

I have a 496, not a 502, and I cruise over 4,000 rpm. I vary the speed and occasionally run up to full speed and back down a bit but usually turning at least 4,000 rpm. Fuel economy???? Can't worry about that in a performance boat. If I wanted to cruise at 2,500 rpm I'd have bought a day cruiser with all the ameneties.

[Barry Eller]

I have a 496, not a 502, and I cruise over 4,000 rpm. I vary the speed and occasionally run up to full speed and back down a bit but usually turning at least 4,000 rpm. Fuel economy???? Can't worry about that in a performance boat. If I wanted to cruise at 2,500 rpm I'd have bought a day cruiser with all the ameneties.


I don't cruise at 2500 RPM'S either, just information in case you are low on fuel and NEED economy to get back in. I have NEEDED to do that before!

All boat tests I read show 2500 RPMS vs Speed to be the sweet spot for BB Marine engines for FUEL economy.

I am nearing completion of my 502 rebuild, it will see 2500 RPMS for approx 30 minutes to break-in the camshaft, then 2500 on its way up to 5000 or so!:yes:

[zelatore]

It's not that I'm looking for economy, more that I'm wondering how the 502 will stand up to running that RPM for say 30-60 minutes at a stretch. I wouldn't want to run it at WOT for an hour, but even though this is a higher RPM than I would normally turn one of my engines, it doesn't seem to be an issue with this set up.

Obviously, I could get better economy and longer engine life if I just got it up on plane and then kept it there...maybe at 2500 or so. But that's not why any of us bought one of these boats, is it? :propeller:

I have noticed that I'm burning a little oil, about a quart per tank of gas. That doesn't seem excessive for a 120 hr motor given the way I'm driving it. But never having owned a 502 before, I just wanted to make sure one of you with more experience didn't say 'oh- a 502 will grenade after 50 hrs at those RPM....'

[BigGrizzly]

The 502 is pretty stout. I cruise about 3200 to 3500 Rpms. I don't cruise higher unless I have to to keep up with Doc and Road trip. the engine will hold up at 4000 Rpms rather well. This is a very durable engine in the marine application.

[MOP]

I would not worry about the quart to every tank, I know a few cruisers that treat their boats very well that burn a quart every 4-5 hours on twins. Being a boat broker I have heard so much about 502 oil consumption that has gotten like hull blisters a not to worry issue.

Phil

[Cuda]

I usually cruise between 3200 and 3500. I imagine that a 502 would last a long, long time running mostly at those rpm.

[gcarter]

I've always like the idea that you can use these boats for actual transportation because the cruise speed is so high.
For instance, Ormand Beach to St. Augustine and back for lunch....about 100 miles RT. You can't really go 60 MPH all the time w/ all the other traffic, barges, large yachts, etc...so in the Minx we would cruise @ 3200-3400 RPM @ about 42-46 MPH and get almost 4 MPG.
Another trip I've thought about a lot is Sarasota or Ft Meyers to Key West....from Sarasota to KW, it's about 100 miles (if I remember correctly and FM is much less). Now if you had a place in KW to tie up, like I do at my friends house on Kudjoe Key, it would be an interesting, much shorter trip than towing around the East Coast and down US-1.
Of course you'd have to pick your weather and time of year very carefully. Not much different than KW to Ft. Jefferson though.

[oldandtired]

I usually cruise around 4000, no issues at all. Engine burns a little oil which is normal for 502's.

Rene

[Cuda]

.
Another trip I've thought about a lot is Sarasota or Ft Meyers to Key West....from Sarasota to KW, it's about 100 miles (if I remember correctly and FM is much less). .
Trust me, you don't want to make that trip in a 22 foot boat. Some friends of mine made the trip a few years ago in a 32 foot cruiser. The weather got nasty, and it took them over twice as long to get there as they figured. They thought they were going to run out of fuel, and were in constant contact with the Coast Guard going across Florida bay. One guy on the boat was practically in tears he was so scared.

Another friend of mine recently made that trip in another big cruiser. His wife was so scared, they took a plane back to St Pete.

Florida Bay can kick up with no warning if the wind comes up, because it's so shallow. If I feel the need to take the 22 to KW, it will be behind my F-350.

[The Hedgehog]

I like 3,800 to 4,000. I am still pulling vacuum and not really burning oil.

[zelatore]

All good info. I had obviously felt 4000 RPM was a decent cruising speed or I wouldn't have been running it. As stated above, I rarely find enough clean water to run that speed more than about 30 minutes straight, but it's good to know others have found the 502 happy at those numbers.

In my buisness, we haven't seen a 502 in ages. I think the last set we had was in an older 41 Silverton Convertible - and I wouldn't want to hold that thing at 4K for long....I don't have the wallet for it even if the motors were up to it! That was a boat desperate for a pair of oil burners!

So I guess tomorrow when I take the 22 out and loaf along at a comfy 4000 RPM blowing past all the ski boats I can just smile to myself and wave as they disapear behind... :wink:

[smokediver]

I've always like the idea that you can use these boats for actual transportation because the cruise speed is so high.
For instance, Ormand Beach to St. Augustine and back for lunch....about 100 miles RT. You can't really go 60 MPH all the time w/ all the other traffic, barges, large yachts, etc...so in the Minx we would cruise @ 3200-3400 RPM @ about 42-46 MPH and get almost 4 MPG.
Another trip I've thought about a lot is Sarasota or Ft Meyers to Key West....from Sarasota to KW, it's about 100 miles (if I remember correctly and FM is much less). Now if you had a place in KW to tie up, like I do at my friends house on Kudjoe Key, it would be an interesting, much shorter trip than towing around the East Coast and down US-1.
Of course you'd have to pick your weather and time of year very carefully. Not much different than KW to Ft. Jefferson though.
Sarasota and fort myers are further than 100 miles ... the trip you might want to try is marco to marathon ... you can put in at caxambas pass on marco and head to the marathon light ... later in the summer early morning it's like a lake and you can follow the sticks all the way down ...