Diesel Power

Jedcraft · 08-11-2007, 07:37 PM

How about some feedback on diesel marine power. Yanmar or Volvo? Any ideas on average on how many hours can be expected on a well maintained-not abused engine? More weight than gas inboard? Reliabilty?

colbachlaw · 08-11-2007, 08:27 PM

Jedcraft,

Go to www.yachtsurvey.com and read the article on gas v diesel.

Diesels are ungodly expensive (70-80K to repower my boat with cummins remans) and require more upkeep.

Mike C

nunyet · 08-11-2007, 08:42 PM

I have had 2 diesel jets....one a 315 cummins and a 274 pump ....big boat 27 feet with a 101/2 beam .....carried a very heavy load ....ran very well easy on fuel.....a little more cavitation than I like, but very manageable in the Deschutes, Snake and Salmon....worked well in the ocean....cruise at 22 hundred rpm 27knots about 8 gallons per hour.wot 28-hundred rpm 40 knots...very good commercial application ..

My present boat has a 315 yanmar with a 241 pump......25 feet long ...7 foot bottom and legal on the road. The yanmar gives gas engine performance ...cruise at 3000 at 27knots and wot at 3900 and 42 knots. boat runs like a sports car...fuel consumtion is a little less but the boat is much lighter...no cavitation... Probably will not run the hours that the lower rpm engine will...the safety of the diesel and economy make it work for me....gas engines are so good now and so dependable there is probably not reason to go to diesel....but how many decisions do we make on want over need?

I would have kept my first diesel if I was not retiring and wanted a smaller boat legal on the road, plus the builder found a mining company in south America that really wanted a boat like it and he did not have time to build it.....this will probably be my last jet boat.....thats a joke with my wife as I have had everything from outboards.....I still keep a little 19 foot alumaweld with a 115 jet on it.......up too twin v8s and each boat was the last one we will ever need. Darrel Bentz has build my last 7 inboard jets and if I ever build another he will be the builder.

nunyet

8knots · 08-11-2007, 09:20 PM

I know it doesn't really relate and they are low horsepower and naturally aspirated, old tech engines...but, I have twin Ford Diesels from 1973 on one of my boats. They have over 4,500 hours, about at their half life. Means I should get another 34 years out of them. Rock solid and easy to maintain.

Grady252 · 08-11-2007, 09:46 PM

Yanmar all the way.... high rpm thousands of hours, not much chance of a fire... way more efficient.....

Mark the Captain of the Pacific Mistress in Depoe Bay, just put a new Yanmar in his and he is real pleased.... jus did the 100 hour service..... I have always heard good things about the Yanmars.

backlash442 · 08-11-2007, 09:56 PM

If not mistaken the Yanmar is lighter than the Volvo. Very quiet. Friend had one in a heavy glass boat ( easily over 6k lbs dry). You could barely hear it when standing next to it. Lots of power. He loved it.

Another friend has the new D4 Volvo. Very impressive performance. His boat probably weighs over 5500lbs dry. He can cruise at 26 knots or so and only burn 8gph. He really likes it. Only thing is it idles at over 4 knots.

Hard to say how many hours you can put on them. I'd say thousands though. Both are pretty reliable but do know of Volvo having problems with valves. KAD 42 I think. Overall though I think pretty good. Know several with them.

Sea Jypzee · 08-12-2007, 03:36 AM

My current boat has an AQD-40 Volvo Diesel and I am extremely pleased with it. It's not fast, can cruise out at about 14-15kts, but it is extremely fuel effecient at about 3-4mpg.

I can't really tell you anything about how it (an older diesel) compairs to the newer Volvo diesels. It's not nearly as loud as gas engines I've had in my prior boats, and everything is much more accessable.

With a little maintenance on it, it will last thousands more hours than a gas engine as well.

As for safety, Diesel is far better than gas on a boat.

Tower Todd · 08-12-2007, 07:00 AM

The yanmars are nice engines but IMHO not on par with the current common rail technology like Cummins or Volvo D Series. If you really serious, then pay the $25 membership to boat diesel dot com. You will find more than you ever wanted to know plus some.

nunyet · 08-12-2007, 08:14 AM

Yanmar does not recommend using the light weight lp series for commercial use. I have a friend that ran them in a triple on the snake. Motors where run at 34 to 35 hundred most the time and starting having valve problems at 350 hours.....also make sure you change the antifreeze every year or serious corrosion problems will cause you to loose a engine. The early 315 had a serious valve problem but yanmar has stood behind them and the engines built after 2002 have not had that problem.

The yanmars that are a little heavier and have a top rpm of about 29 hundred make a great commercial application .

One of the things to consider in putting a diesel in a jet boat is the cost of the pumps......the 241 and 274 hamilton jets run between twelve and sixteen thousand......so your looking at over 35 just for engine and pump.

nunyet

Jedcraft · 08-12-2007, 05:41 PM

Am looking at a 2000 Osprey 24' with a 190 hp Yanmar with prop drive.
400 hours on boat.

Reelentless · 08-12-2007, 07:45 PM

Quote:

Originally Posted by Jedcraft

How about some feedback on diesel marine power. Yanmar or Volvo? Any ideas on average on how many hours can be expected on a well maintained-not abused engine? More weight than gas inboard? Reliabilty?

I have twin Yanmar 4LH DTE 170's in my 28 Bertram. I burn 9 gallons total at 18-20 knot cruise. Not a rocket, but at 2mpg, its relatively economical and has twice the range of a gas powered version. The engines have over 2000 hours on them and run like new. Just like Volvos, parts are very expensive. I just replaced both mixing elbows at $800 each. Cummins are cheaper, but the 6 cylinders wont fit. The 4's are too shaky.

A diesel in a 24' boat isnt real cost effective unless you can buy the boat cheap. A gas powered version will have plenty of range and power to do everything you want.

In summary, the 4 cylinder Yanmars are great little engines if they are maintained. Get a good survey before you buy.

Edit:

I would be a little concerned about a 7 year old diesel with only 400 hours on it. Diesel engines dont like to sit around. They need to be run. Again, make sure you have a qualifed diesel mechanic look over the engine.

Pelagic Captain · 08-13-2007, 05:37 PM

Quote:

Originally Posted by Jedcraft

How about some feedback on diesel marine power. Yanmar or Volvo? Any ideas on average on how many hours can be expected on a well maintained-not abused engine? More weight than gas inboard? Reliabilty?

My boat , a 96 model 24 ' seasport is powered with a volvo DP 41 in line 6 cyl. The boat has under a 1000 hrs. of service and I'm told to expect at least 3000 plus hrs. of service . I change oil and all filters every 50 hrs. It does not burn any oil and runs great. This engine is marine quality and will hold up for a long time. They are heavy ...my hole shot is non existant...slow wind up is frustrating but it will haul a load and gives excellent economy.They are loud even with a sound insulation pak which I have but not much worse than my old gas powered seaswirl.The folks at Boondocks in Bellingham can can give you some specifics and comparisons.

tomictime · 08-13-2007, 08:29 PM

the I/O is the weak link
you can get close to 3 MPG with Yami F4-250 or Suzy on a 24' Osprey..and more cockpit space, and a MONSTER fishbox where all the iron was.
oh and an idle speed that is fishable for salmon, subtle docking, etc..
Diesel inboards are a different story.

Pau Hana · 08-13-2007, 09:48 PM

Diesel I/Os are fine- they're fuel efficient, fairly quiet, and robust. A few friends in San Diego repowered from gas v-8s to the Merc 1.7 diesel- in both cases, mpg went to between 5 and 7, with the major tradeoff being a loss of top end (a few mph).

Well worth it in my opinion.

Chrome Bumper · 08-13-2007, 09:49 PM

If you can get the new one with the douprop. Great power plant/outdrive.

The Yammars are fine engines, but get the volvo douprop package if you can.

Pau Hana · 08-14-2007, 06:03 AM

Quote:

Originally Posted by Chrome Bumper

Volvo does not build their own engines. If you can get the new one with the douprop. Great power plant/outdrive.

The Yammars are fine engines, but get the volvo douprop package if you can.

Huh? VP doesn't build their own engines? They sure do.....

Think you're a bit misled on that...

MyHarbor · 08-15-2007, 06:43 AM

Yanmar does make a common rail technology in the BY series.

Quote:

Originally Posted by Tower Todd

The yanmars are nice engines but IMHO not on par with the current common rail technology like Cummins or Volvo D Series. If you really serious, then pay the $25 membership to boat diesel dot com. You will find more than you ever wanted to know plus some.

Chrome Bumper · 08-15-2007, 08:35 AM

Quote:

Originally Posted by Pau Hana

Huh? VP doesn't build their own engines? They sure do.....

Think you're a bit misled on that...

My bad