bertram31.com

The engine specs say fuel consumption is 11.2 GPH at "rated conditions".
Does that mean I should expect to burn somewhere around 22 GPH at cruise? (Twin 210's in a B28)

I know weight, hull type and props are variables but how is the 11.2 GPH arrived at I wonder? Is that under some kind of maximum load I never approach or is it a realistic indicator of what I'm burning?

I cant see how it would burn that much. My Yanmar 315s burn 11 gph a side going 28knts 22 gph. My buddy has the 6bta in his boat and they burn the same as me and his are 300 or 330 hp

I have 210's in my 31 Sportsfisherman with 20X20 cupped props. I cruise at 21-21 at the end of the season with a dirty bottom, but I don't burn anywhere near 11 gph per. I burn about 8 gph per and almost always get 1.5 mpg. The engine's WOT is 2600-2650. My cruise is at 2350-2400. Mine is an early model with a heavy hull, heavy teak deck, gin pole and big tuna chair. I would think you'd do a lot better with your 28. Walter

The Cummins 210 fuel flow chart is available @ Cummins.com Here is what i found:2600-12gph 2400-9.2gph 2200-7.2gph 2000-5.9gph 1800-4.6gph 1600-3.5gph 1400-2.7gph 1200-2.0gph 1000-1.6gph 800-1.3gph. These specks are @ prop load which means under normal/propped correctly load. This engine may actually burn less if propped light or more if overpropped. Hope this helps. Troy

Thanks guys. Troy, the numbers you provided were more like what I was thinking (low teens total per hour). I usually cruise between 2100 and 2300, though the hull seems happier the faster I go.

Steve,

I used to cruise at 24 knots @ 2400 and would see around 1.25 MPG. Since adding 1500 lb. of lead to the boat I have lost about 1.5 knots of cruise and now get between 1.0 and 1.25 mpg.

Dan

Dan,

Do you have the same boat/engine combo?
Why did you add 1500 lb of lead to the boat?

Any concern w/ running the engines at over 90% WOT?
(I've come to the realization that for as much as I run mine I might as well run it at 2300-2400 since I have little chance of wearing them out)

Thanks for the info.

-Steve

Steve,

All my hours are running charters, 1000 hrs this season alone, and customer comfort is one of my top concerns. The boat rides WAY nicer with the added weight especially in our average 3 ft. seas. I decided it was worth the trade-off to give up the knot or two in calm seas to have the smoother ride in the choppy/rough stuff. In my 95+ trips this year I could count on two hands the days that were calm enough to run over 23 knots comfortably anyway. As for longevity, I turn 2580 at WOT. I hear guys saying that's not enough, my engine hours, almost 6000 say otherwise, and they are still running strong. These engines are arguably the toughest that Cummins ever built. A freind of mine has a pair in a 38' wooden Carolina hull that tips the scale at nearly 35K lb. His engines have nearly 12000 hrs and still run fine.

Dan
www.finchasersportfishing.com

The engines properly propped should WOT under load at 2600. With no load at the dock and in neutral, it should turn up 2850. If not, the injecter pump full throttle stop is not set properly, or your throttle cable isn't throwing far enough. That being said, mine were set improperly from day one and I hit 2600 with every prop I tried from 20 x 18 to 20 x 20 cupped. The insanity of that had me finally find a Cummins trained mechanic who solved it. The adjustment is easy, but is usually wired with a seal that has to be cut off. Obviously, you are better off with being a bit underpropped. In the case of our 210's, we have the most bulletproof of the 6bt series. Walter

Walter how did you know it was set incorrectly if you reached 2600 no matter what wheel you had on it? I reach 2650 with a full load, 20 x22, 4 blade wheel, 6bta's, 270's. Is it the 2850 in nuetral to see if it's set properly? thanks Russ

Russ-Your 270's may have a different no load top rpm. The spec (according to what the Cummins Mechanic told me was 2850 for the 210's. Being conditioned by gas engines, I never even considered "red lining" my engines to maximum rpm's at the dock. Thus, when I briefly ran to WOT under load and hit the 2600-2650 rpm's, I thought I was OK. Being dissatisfied with my speed, when I reconditioned my wheels, I decided to add an inch of pitch to the wheels. I immediately added speed and still could hit 2600 rpm's. After doing that twice and going from 18 kts cruise to 21 kts and still hitting the proper max rpm's, I questioned the whole process as it related to my engines. It was then that I was told that my max at the dock under no load should be 2850 and that I would not damage my engines by revving them to max for a short period. That's when I discovered that my engines were governed to 2600. That governing is really just a set screw that stops the forward thrust of your throttle cable. It can be easily adjusted...but mine were adjusted incorrectly and sealed to stay that way, so I never questioned it. If your engines at no-load hit 2850, you will have the proper props if under load at WOT you turn 2600-2650. If you don't reach those numbers, you're over propped and should cut back on pitch or diameter. If you exceed those numbers, you are under propped and can add pitch or diameter (or cupping). It is better to be a bit under propped than over propped in terms of engine longevity. Without your engine being able to go over the 2600 rpm's, it's almost impossible to figure out the proper prop until you over prop and then cut back. Hope this helps. I found out far later than I should have. Walter

Capt Walter....Have you ever tried larger than 20X20X3 and found out where is too much wheel? Troy 31Tiara"DRIFTER" Lafitte,La
I am using 210 re-mans for this Tiara express and have a 20X22X3 and a 20X22X4 to play with to start. They are both probably too big. 15000lbs 12ft wide 16degreeV. The 4 blade is in perfect shape and the three is pitted real bad and just for testing.

Troy- As of this moment I haven't. Having just made the rpm adjustment, I will see if I can add more pitch this weekend. Your props can have pitch added or removed by a good prop shop. Given the price of props nowadays, try them and then adjust accordingly. I would suspect your boat, not having the real deep V of the B-31 might not have a problem with one of those sizes.

Troy- I ran the boat to Fischer's Island after the no-load adjustment to 2850. WOT jumped to 2725 with my existing props. This means (to me), my 20x20 cupped props can be upped to 20X21 cupped or 20X20 super cupped. Since I do a lot of Bass trolling, I'm not inclined to do anything that would effect my "slow" end so I will discuss the degree of cupping with Bosler and Sweezy, my prop shop. I would never have known had I not run into this Cummins Mechanic. Waler

now now lets not let the cat out of the bag walter.phil the owner of B&S said super cupping is top secret!!! remember my 31 bert "phoenix"at montauk doing 33knots in the ocean.well that suppercupping had a part in it.walter don`t ask him about "skewing"the props you may have bluebeard leaping out of the water!! ------tell phil i said hello

Thanks Capt Walter.