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F25 Diesel Engine
Posted: Mon Feb 15, 2010 9:43 pm
by Rodman
I have friend that bought my F25 wants to know what diesel engine is best for that boat?
Posted: Mon Feb 15, 2010 11:10 pm
by prowlersfish
It will be tight fit a 6.5 gm may work but I don't think its a great marine engine . Yanmar would be a good choice also as long as there is room . I belive it is a V-drive ?
Posted: Mon Feb 15, 2010 11:22 pm
by Rodman
prowlersfish wrote:It will be tight fit a 6.5 gm may work but I don't think its a great marine engine . Yanmar would be a good choice also as long as there is room . I belive it is a V-drive ?
No its not, It has transmission in the rear . The motor is backwards from my F26. the belts on the motor is facing front of the boat.
This is how the motor looks in the boat. Got this from Paul`s Ca photos.

Posted: Tue Feb 16, 2010 6:15 am
by prowlersfish
You are limited in choices due to height and length . a down angle trans may help on the height some what . The only choices i can think of are a yanmar 4 cly ( I believe a 6 Cly would be to long ) or the 6.5 . Again I am no fan of the 6.5 in a boat ( I like them in a truck) The Yanmar may be the best choice . But I would do a lot of measurements . And remeber there is a lot more to putting a diesel in the just changing the engine
Posted: Tue Feb 16, 2010 7:15 am
by foofer b
Rodman, how much would a used diesel cost. Would you ever recoup the expense in fuel savings? Don't diesels turn less rpms generally so their horsepower is derived from more torque? Would you need a larger prop to put the rubber to the road so to speak? Is a more highly pitched prop do it? Can you fit any larger diameter prop?

Posted: Tue Feb 16, 2010 8:04 am
by Rodman
Ill pass the info along to my brother in law. He is the one that bought my F25.
Posted: Tue Feb 16, 2010 8:12 am
by ready123
I would think on such a small boat the weight penalty of diesel might not be worth it for any real fuel savings over gas installation.
Posted: Tue Feb 16, 2010 9:57 am
by MattSC
When I did my repower I looked into a diesel engine. The yard which specialized in gas to diesel conversions recommended a Yanmar 240HP 4cyl. diesel. It has more torque than the old 318, but there are other things that will need to be changed, including the shaft which will require a 1" 1/4 instead of 1", new strut/cutlass bearing, shaft log, fuel tank etc... The engine/trans was 17 or 18K that was in 2002.
http://www.yanmarmarine.com/index.cfm/g ... t-engines/
from the drop down menu select 4LHA-STP-240
Posted: Tue Feb 16, 2010 10:56 am
by Stripermann2
Matt is on to it... This guy did a repower on his Carver recently and used the Yanmar 4 cylinders with some impressive numbers.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=133902
Diesel repower
Posted: Tue Feb 16, 2010 11:27 am
by gettaway
Please find the attached article regarding this topic, cutting to the chase, diesels are exensive to buy and maintain and you'll have to put hundreds of hours a year on your boat to recoup the savings in fuel.
http://www.yachtsurvey.com/GasDiesel.htm
Posted: Tue Feb 16, 2010 11:49 am
by ready123
I agree that diesel conversions are not worth the time and money... if you want diesel then buy a diesel boat... don't put the money in to convert a gas boat.... it is so much more than just the engine that needs to be modified and often corners get cut.
Posted: Tue Feb 16, 2010 12:04 pm
by prowlersfish
yes it cost more and it may not pay for it self , But it can be worth it only once you have owned one could you under stand . most that have will never go back to a gas boat .
As far as yacht survey goes he is more opinionated then anyone here( incl me) . he clearly hates Diesels has a lot of miss and out dated info on them , and Yet he owns a diesel boat . so take what he says with a grain of salt .
But different stroke for different folks
But would I put a diesel in a F25 ? not unless its was free
diesels
Posted: Tue Feb 16, 2010 12:09 pm
by gettaway
I have had a hard time with this topic, I have owned a 34' CHB sedan Trawler for the past 16 years, she is powered by a single 120 hp Ford Lehman enigne and a pargon transmission. for a trawler semi displacment hull with a displacement of 26,000lbs, and a hull speed of about 7 knots, it is perfect and the enigne just runs and runs and runs. cruise speed of 2100 RPM and sipping a mere 1.7 gallons an hour. Of course my friends that cruise at 12+ knots are all on a mooring in Mission bay or in Catalina hours before me, but I have justified the speed with the incredible journey that it always turns out to be.(you must have autopilot at 7 knots) Life changes and time has become more "valuable", and I just don't have the spare time I used to, nor do I want to spend the extra $ 60,000 a 32-35 foot sedan / convertible sportfisher boat would cost to buy it with diesels. therfore, the trawler is sold and a Trojon F-32 is in my sights and hopefully in my slip within the next month or two. with 250 hp gas crusaders. The search over the past few months came down to; another 34' trawler, a Viking 35 convertible with 300 hp gas and a Trojan F-32. The Trojoan is a lot of boat for the money, they seem well built and a great layout for a family weekend pretty much anywhere. Having a Flybridge trawler with upper and lower helm stations, I operated the trawler from the lower station about 95% of the time, it took heavy seas heading north from Ensenada Mexico back to San Diego that made me appreciate the comfortable ride from just above sea level, operating from 12' above in rough seas is / was a sure path to seasickness. The view is great from above but with the little bridge on the Trojan, the company and crew will be below anyways.
Posted: Tue Feb 16, 2010 12:58 pm
by MattSC
I had wrestled with this decision several years ago. I wasn't nor am I planning on upgrading to a larger vessel which is why I decided to undergo a repower job. I had interviewed several yards before I chose one to do the job, as well as researching the idea of installing a diesel engine. I chose to go the route of installing a fuel injected Crusader and couldn't be happier with it. Another thing to keep in mind is once you start you will find other items that will need to be addressed. I was lucky enough that I had a good yard to do the job. We encountered several issues, which with their help were corrected and the installation has been trouble free over the last 7 seasons. Enough can't be said about sticking to a very strict maintenance schedule and correcting any minor problems before they become major
Posted: Tue Feb 16, 2010 4:07 pm
by Danny Bailey
Back in the early 90's I bought a new Cummins 6BT210 and put it in a 28' Chris Craft. It all worked out great, but I would not do it again. Go find a boat that already has a diesel in it, and buy it. Less cost and less headache.