Repowering with Yanmar turbo-diesel etc

Recently I have my hooks into a Yanmar 4JH4-HTE turbo diesel. This Yanmar has 2000 hours on it, new alternator, engine mounts, etc and a rebuilt KM4A transmission. The price is $5700 complete. Question: Has anyone installed a 4 cylinder Yanmar as a repower ? If so I would like to hear all about the issues a project such as this can produce. Best wishes, Jeremy and Jane Parrett (#101, Two Pelicans).

a. Some loose thoughts re: your repower …….. Having repowered ( former #186, Visitant ) to a new 50 HP Beta BV2203, the big issue with me was the mounting. Specifically: Compatibility with existing engine bed, incl. the final alignment of the shaft with the boat’s Stuffing Box.

In my case, since I did not want to do this at the boat, I had the time to duplicate the existing engine bed in my shop and only minor re location of the Beta engine mounts were needed to meet up with the old engine bed. Obviously you need to research the Yanmar foot print prior to …….. or have the Yanmar engine on hand. By having the duplicate engine bed off site, allowed me to align everything incl. the final height ( angle ) of the drive shaft / engine before-hand and all that was done on site was re drilling the engine mount in the boat’s bed. In my case, there was a 3/8″ thick s/s flat bar moulded into ( inside ) each length of engine bed stringer. You can re drill and re tap it, or some people just lag bolt the engine mounts.

Regardless how you proceed, I would strongly suggest installing a ” squeeze ” bulb on the fuel supply line. This will allow you to prime the fuel filters etc. by hand until you hear the fuel returning to tank. Doing this I have NEVER had to air bleed the system, esp. after filter change.

You may also want to service your Stuffing Box, ie. new or double clamps, shaft seal, packing ( put 1 xtra ring of it ) incl. tightness as this will NOT be accessible after the engine is mounted.
Hope that helps, good luck Jeremy & don’t hesitate to write if you need more. Frank Bryant (#186, Visitant).

b. Before taking my Corbin down through the South Pacific I replaced my old Volvo engine with this same Yanmar. The engine ran beautifully for the whole 4 years but there were problems with the installation. The transmission is a 2 to 1 ratio. My existing V drive is also with a 2 to 1 ratio. One had to be changed. New V drives would not fit into my boat without major changes so a ZF hydraulic transmission was added to the Yanmar. The transmission failed several times until I got it properly overhauled in Australia. (Another problem with a hydraulic type transmission is that it does not stop the free wheeling of the prop under sail.) My Yanmar now has over 2500 hours and runs very smoothly and dependably. It is a very common type of engine in the South Pacific so parts and help is available. The price sounds great, I ended up with a total bill for $25,000 for one installed new. Good luck, and great sailing. Nick Fenger, (#038, Dragon Star).
c. We just repowered with a Yanmar 4jh5e, not the turbo but the naturally aspirated version. Am ecstatic about the result, now doing 8 knots at 3,000rpm if needed, cruising / motorsailing at 6 knots with 1500 rpm. In my case the transmission was too long and had to be replaced with a shorter one so that the front of the engine could be raised so that the shaft would meet the transmission flange. Engine bed was redone twice at my expense although the installer screwed it up. Make sure your prop matches the engine too. Write if you have questions. Gerry S. (#087, Octopus I).

d. Yes, I have recently repowered from a Westerbeke 38B to the bigger Yanmar. Also with the km4a tranny with zero angle. We had to modify the bed rails slightly and raise the doghouse about 3 inches. The exhaust had to be upgraded to 3″ and a new prop fit to handle the horses. What a difference in overall close handling and backing! If you do go ahead with it make sure you are prepared for a major upgrade and not just a motor swap… Fair Winds Keith B. (#025, Agape).

e. The specs state that the Yanmar 4JH4 HTE is a 110 HP Turbo. For what it’s worth, Beta is Kubota based, a simple & uncomplicated ” Cast Iron ” engine that is widely used in mining equipment etc. or where the eqpt. runs 24/7 for days on end. I was not involved in the calculations regarding the HP / Transmission or the Prop Size / pitch etc. for a given boat, It is done by people much smarter than I. Suffice it to say that the Gearbox ( if it comes with engine from the factory ) is always sized to accommodate the HP of the engine, the important variable being gear ratio. That is important with regard to the output shaft speed for a given type of prop. That’s why it’s worth looking at adjustable pitch prop, as no matter what one calculates, it will NOT be the right thing and would need to be field adjustable. Cheers, Frank Bryant (#186, Visitant).