[mondofromredondo]

Hi all,

Been trying to figure out my fuel burn but after all these years am realizing I've paid very little attention as I only fill up twice a year.
Can anyone give me an idea of my fuel burn per hour or range?
I have a 3HM30F engine I belileve on a PSC 34 with a 35 gallon tank and I average about 3k RPM.

Thanks
Keith
PSC 34'
S/V Charity Rose

 

[JohnRPollard]

Keith,

A lot of variables there, especially when trying to calculate range. Such as your prop; transmission; adverse or beneficial wind and current; how laden the boat is; clean or fouled bottom and prop; etc.

Burn rate should be a bit more predictable, based on the consumption curves provided by Yanmar and your own measured experience. If you could record the number of engine hours each time you fill up your fuel tank, that would be one of the best indicators.

We've typically averaged about 1/3 gph burn rate with our 3gm30f. We push it hard when we use it, but that figure also includes some warm-up and cool-down time at idle. With your larger engine, you can probably expect to use about 1/2 gph at 2800-3000 rpm (but check the Yanmar website for their calculated figure, too). Then you can plug that in and figure your range, recognizing that the variables I mentioned above will affect the final figure.

 

[mondofromredondo]

Thanks John,
I certainly realize that by paying attention to burn time versus fuel consumption shown at the pump will give me the value I'm looking for. But I could spend the next 3 months waiting for enough opportunity to burn enough fuel to make that calculation. I was just looking for ball park value.
I'm hoping someone with a 34' with the same engine would have that number they've been working with.

Thanks again !
Keith

 

[johnharch]

Fuel burn

I have a Yanmar 3HM35F on my 34. I keep a log of my fuel usage, but due to use of the diesel heater and time running the engine at anchor to charge batteries and holding plate, it is kind of hard to come up with a good figure. I think I use about 3/4 gal/hr when under way.

John

 

[wsmurdoch]

The only thing I know about the fuel burn rate is that it varies.

This year in late January and early February on the way south to the Bahamas via the ICW we filled up at NW Creek Marina before we left. Call it 20 miles from the marina whch is near New Bern, NC to Cedar Creek (SM 187.5) and 394 miles to Savannah Bend Marine (SM 582.3) where we refueled taking on 43.1 gal in the tank and the three jugs we carry on deck. That is 414.8 statute miles on 43.1 gal or 9.6 statute miles per gallon or 8.5 nautical miles per gallon. We usually run 2500 rpm and most of that was in flat water with little wind. The bottom and prop were both clean. We made only a few side trips to anchor and sailed very very little.

Three or four years ago we burned almost 3/4 tank crossing the Albemarle Sound from the Alligator River to Elizabeth City when we had no business at all doing it. A large Silverton behind us separated its hull to deck joint, sank, and the two on board were picked up by a USCG helicopter. It was a seriously rough day.

Bill Murdoch
1988 PSC 34
3HM35F Yanmar (5272 hr)
Warderick Wells, Exumas, Bahamas

 

[mondofromredondo]

Bill,
Great info ! Thats exactly the kind of info I was looking for.
I see u have your engine showing 5272 hours. Thats an amazing number. These motors are amazing. I have about 700 hours on mine. Any tips above and beyond the required maintenance you'd reccomend to get that kind of life out of my motor?

Thanks
Keith
1988 PSC 34
S/V Charity Rose

 

[wsmurdoch]

Only the last 1000 to 1200 hours are mine. The two previous owners would be a better source of tips. It is obvious that this boat has not been a dock ornament for much of its life. It has Kollmann engine drive refrigeration (with a backup 125v system) and in the past had a watermaker leaving me to guess that the engine has been run daily for long periods of time.

As for preventative maintenance, I changed the oil and oil filter every 150 hr and the fuel filters and antifreeze once a year. I've cleaned the fuel tank once. I replace the raw water impeller and clean the air filter yearly.

On the fix-what-broke side, the biggie was replacing the transmission which failed shortly after we bought the boat in 2004. I had a new one installed and the old one was not dismantled and inspected. It had was filled with 30W oil rather than ATF, and the mechanic guessed that had hastened its demise. I have replaced ALL of the original corroded engine wiring, the alternator and its regulator, the engine mounts, both fuel pumps, the control cables, and the starter solenoid. The cover plate at the back of the engine head corroded through, and I replaced it. I tightened down a loose injector a few weeks back.

The valve lash should be checked, and I have a replacement rocker arm cover gasket to do it, but I have yet to get the roundtoit.

Bill Murdoch
34' PSC 1988
Irish Eyes
ex Jester
ex Diastole

 

[mondofromredondo]

Bill,
Pretty impressive!
It has been 2 years since I've had my raw water impeller changed. Probably due. It puzzles me why Yanmar would have made the access plate face aft rather than fwd on this engine. U need small fingers and the ability to read brail unless you want to remove the entire pump which may be the way I go.

Alas my fuel shutoff cable has corroded to the point where it no longer has any mobility at all. I've not seen one out there for purchase as of yet. Did u go to your local marine supply for this item? I've also heard that they are sometimes available in different qualities ie; sealed, teflon coated etc; I'm guessing the standard run of the mill unit will work. Did you go this route?

Thanks,
Keith

 

[wsmurdoch]

My failed (corroded) control cables, all three of them, were standard red Teleflex cables. For each one I just pulled out the old cable, took it to West Marine in one case and to Roy's Marine in the other two, layed them out on the floor, and the sales chap picked out the perfect match. They kept the old one, and I took the new one. More time driving than fixing.

My wife tells me, and she is right, that I also replaced the shaft seal on the raw water pump, the cover plate, gasket, and the cam (the little hill) in the pump last year. I forgot. Not a hard job either. I already had the pump off the engine to replace the impeller. No big deal taking it off. Only two bolts and two hose clamps hold it on. It was, however, a two hour drive to Oriental and back for parts.

Bill Murdoch