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-   -   Gallons / Hour with a Yanmar 3gm30 (http://www.cruisersforum.com/forums/f2/gallons-hour-with-a-yanmar-3gm30-12272.html)

Dave in Eugene 17-01-2008 17:05

Gallons / Hour with a Yanmar 3gm30
 
...ok I know that different boats / props / loads / RPMS will affect fuel useage...but in general if you have a Yanmar 3gm30 could you please share the following:

1) Value you use for fuel burn
2) your cruising rpm

Thanks in advance,

Dave

never monday 17-01-2008 17:23

.75@2500rpm

Kanani 17-01-2008 17:26

They burn about 1/2G per hour @ 2500RPM on a 36' sailboat with a clean bottom @ about 6.5kts.

That was in a Catalina 36 (with a 3GM30 and 3 blade prop) that I delivered from Ft. Lauderdale to Panama. I motored ever inch of the way. Never saw a bit of breeze. I stopped in Jamaica to refuel because I only carried 50G (including 30G in jerry cans).......what a bumber. I used 80G of fuel to motor approx 1100 miles.

maxingout 17-01-2008 19:17

On Exit Only we had two Yanmar 3GM30 freshwater cooled diesels. We would cruise using one engine at a time - 2200 RPM using one-half gallon per hour. If we were going to motor for long periods, we would use the port engine for twelve hours, and then the starboard engine for twelve hours.

With jerry cans, flexible fuel tanks, and permanent engine room tanks, we reckoned that we could motor 1400 miles on the fuel we carried on our Privilege 39 catamaran.

scotte 22-01-2008 08:04

We have the same boat as MaxingOut - Privilege 39 with 3GM30s - with similar economy. On our recent delivery (3 days straight motoring) we ran at 1900RPM with both engines and estimated our fuel consumption at about 10 gallons per engine per 24 hours.

Charlie 22-01-2008 08:21

My experience is with a 4JH4E and I ran at 2500 to 2800 rpms and I burned around 5/8 to 3/4 gallon per hour.

Charlie 22-01-2008 08:23

Not to steal the thread but my understanding is that it is not good for the yanmar engines to run at lower (say less than 2000 rpms) for extended periods of time. Is this true? Can anyone back it with evidence.

Alan Wheeler 22-01-2008 10:31

Charlie, that depends on many other issues. Is the idling with no load, is it idling with load, is it running at say 1900 under load or is the engine over loaded and so on and so on. If running at low RPM, the recommended procedure is to run the engine at full RPM for a few minutes once every couple of hrs.

Strygaldwir 22-01-2008 13:35

I have 2 3ym30's. They are the replacement for the 3gm30. I cruise at about 2200 rpm with one engine at a time and us just over 1/2 gallon per hour. I cruise at about 6.3 kts at that rate. I will usually alternate engines after about 6 hours of run time on one.

I have a privilege 37 catamaran. Oh, and I am slightly overpitch on my props. Wish I could afford feathering or folding props I think given that I run on one engine it would add significantly to my performance.

Keith

AnchorageGuy 22-01-2008 16:21

Sometimes it will burn 1/4 GPH, sometimes it will burn 1/2 GPH, sometimes it will burn 5/8 GPH. And all of these are right and all of these are wrong. You can get estimates for fuel consumption for that engine from a good Yanmar dealer but sometimes it will be right and sometimes it will be wrong. Only by doing sea trials with your boat under varying conditions and RPMs can you answer your question. Anything else is just a wild ass guess or WAG for short.

Charlie 22-01-2008 17:08

Quote:

Originally Posted by Alan Wheeler (Post 128033)
Charlie, that depends on many other issues. Is the idling with no load, is it idling with load, is it running at say 1900 under load or is the engine over loaded and so on and so on. If running at low RPM, the recommended procedure is to run the engine at full RPM for a few minutes once every couple of hrs.

Thanks Wheels.

never monday 22-01-2008 17:11

Quote:

Originally Posted by Chuck Baier (Post 128127)
Sometimes it will burn 1/4 GPH, sometimes it will burn 1/2 GPH, sometimes it will burn 5/8 GPH. And all of these are right and all of these are wrong. You can get estimates for fuel consumption for that engine from a good Yanmar dealer but sometimes it will be right and sometimes it will be wrong. Only by doing sea trials with your boat under varying conditions and RPMs can you answer your question. Anything else is just a wild ass guess or WAG for short.

Chuck,
I gotta disagree...
When planing I assume 1gpm for a diesel up to about 40hp. Just as, I flight plan 10gph for a C172. Of course your results may vary. I'm comfortable with these number and feel I'll have a nice reserve.

Palarran 04-02-2008 17:45

How much diesel do you guys (maxingout, stryglater, and scotte) carry on your Privilege's. Maxingout, how many miles have you actually motored to get to a destination? Also, if your using the large flexible fuel tanks do you just strap them down in your cockpit? I'm really glad you all are discussing this as I've wondered about the motoring range and fuel capacity of cats.

scotte 04-02-2008 19:03

On ours we've got just over 100 gallons in two SS tanks (something like 52 gallons for each engine). We also carry approx 50 gallons in jerry cans, plus another 20 gallons in a dedicated genset tank.

David M 04-02-2008 19:58

Manufacturers can provide you with fuel consumption curves so you don't have to guess. There are also aftermarket fuel consumption gauges that measure rate and total burned...such as Floscan brand gauges.


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