I know there have been threads on this in the past but I can't get by the security letters to use search,, and when I do, an "engine rpm" query gives me a message that my query is under 4 letters and thus too short so.....
I normally run at around 2000 to 2400 rpm when cruising. and sometimes even lower. I was out with some friends and they said they normal cruise around 3200 rpm, claiming that its better for the engine to run at the higher rpm even for hours on end.
I know for a fact that you don't want to run not under load (to charge the batteries for example) but I was wondering what others cruise at when they have to run a distance?
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Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ
Chuck
Did your friend who cruises at 3200 ever have his gauge calibrated? When mine says 3200 RPM it is really doing 2800 RPM. What is their speed through the water at 3200 RPM? This would be a hint that their RPM's is off.
A timing light is avaiable through the C36 "Tool Box".
__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050
Our M25 has a 15x10 fixed. Our engine goes to 3000 WOT out of gear and in gear. We cruise at between 2450 and 2600, 6+ knots. Anything over that is either an emergency maneuver, "blowing out the carbon," or just for fun seeing how fast we can go to check the condition of the bottom or the latest check on how well our quarterly diver did his work! Very Happy 2650 engine hours.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
and to think I just hit 535 hours; I just hate to motor:D
Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay
Chuck,
I had the same problem with the search engine. You can not use any word less than 4 characters in the search field. That had me going crazy for a while.
"Lori Lee"
San Diego, CA
1983 C36
Hull # 0083
Chuck
Enter "Engine Speed" in the search and you may find some entries that you are looking for.
__/)__/)__/)__Capt Mike__/)__/)__/)__
Punta Gorda Florida
1990 Std WK M35 Hull #1050
Thanks for the input. I was doing 6.5 kts at 3200 rpm, but that was SOG so obviously the tide has an effect. They claimed you should run it about 85% of top rpm... not on the guage, but open it up full, then pull back on the throttle about 1/4 to 1/2". This gave me the 3200 on the tach, whether the tach is reading accurately or not.
Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ
We get 6 knots at 2100 in reasonably calm conditions. I cannot stand the racket and general feeling of busyness at anything over 2400. Lately since we're out for the summer and going nowhwere on any sked we are using 1500 which gives close to 5 knots and outstanding fuel economy. We have used 3 gallons since June 20. I think the people who tell you to run it flat out, or close to that must be engine rebuilders since they are the only ones, aside from big oil, who will benefit from that. I am not worried aboout it not be worked hard enough, there is a big difference between spinning an alternator and pushing 21000 lbs of boat. You can overwork a diesel they do not have a 100% duty cycle, especially these smaller units that were largely intended to do light/medium duty work like cutting grass. But as Stu says, your boat your money.
2100 - 2200 for me @ normal cruise. (Gives me 6.5 kn)
1900-2000 for fuel economy.
I would never run it over 2500 for any extended periods....
---- Howard & Linda Matwick ----
--- S/V "Silhouette" - Nanaimo, BC ----
--- 1999 C36 MkII #1776 M35BC ---
Chuck,
The first think I would do is to calibrate your tach. It is obviously WAAAAY off, as are most tachs on most boats, even fresh off the assembly floor. Then you can compare accurately. Just a thought.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
A note of caution, we have a mixed audience in this post, there are folks with the M25 and those with M35 engines, 2100 RPM will not likely get you 6.5KTS on an M25 powered boat. 5.5KTS Maybe.
Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas
[QUOTE=Steve Frost;13761]A note of caution, we have a mixed audience in this post, there are folks with the M25 and those with M35 engines, 2100 RPM will not likely get you 6.5KTS on an M25 powered boat. 5.5KTS Maybe.[/QUOTE]
True enough Steve; and my 6.5 knots is also with an autoprop, (which gives higher speeds with lower revs) - lots of variables which shows that there are never any 'pat answers'.
---- Howard & Linda Matwick ----
--- S/V "Silhouette" - Nanaimo, BC ----
--- 1999 C36 MkII #1776 M35BC ---