1985 Nanni Kubota Diesel: Marinized Parts

“Do you have a manual for this Nanni Kubota Diesel?”  The first words out of Diesel Don’s mouth sent me to the file where we keep all the boat systems manuals.  We had two big thick books, I’m sure we have a manual.  After pulling out the books, Diesel Don informed me that sadly, no we don’t have a mechanic’s manual but that he’d take a look anyway.  As the diesel fired up, the rumble and boat shaking resumed just as in Hawk Channel – I love it when a problem is repetitive instead of elusive.   Usually when we try to replicate something for an expert, the system decides not to perform at that minute.  Rumble rumble, shake shake.   After spending some time with the diesel on and off, Don informs us he has no idea what the problem might be, but we should start with the transmission.  Unfortunately, the Nanni Kubota diesel has a V-drive configuration because there was no room for a 4 cyl diesel in a Passport 37.  Hmmmm….  our first indication that maintaining this diesel was not going to be easy.

1st Two Photos:  No Wind, Motorsail Crossing from Isla to Charlotte Harbor, FL

1st Two Photos: No Wind, Motorsail Crossing from Isla to Charlotte Harbor, FL

We briefly discussed repowering with Diesel Don and his response was that before he took at look at our diesel, he would have recommended repowering, but the diesel looks in good shape and his opinion was it should run forever given the right maintenance and care.  Hmmm…  so does that mean he BELIEVES what he’s saying … or is it an indication that he has NO interest in repowering this boat given the space constraints.    It’s difficult, but he’s been so highly recommended so we go with our gut instinct which is to trust his opinion and let him remove the transmission and dig into the diesel.

Transmission out and tested reveals absolutely no problem except maybe a leaky seal.  But a leaky seal wouldn’t cause the dramatic rumble that shakes D Dock itself, not just our boat!  Back to square one.  The transmission is reinstalled and a host of diagnostic procedures ensue.  The final diagnosis is a motor mount.  When inspected, it turns out that all of our motor mounts are insufficient size to hold our rumbling powerhouse, even if it is only 30 horsepower.  So, Diesel Don recommended replacing all the motor mounts.  He also thinks that if we’re seriously planning to go cruising in this boat (of course we are!!!), we should replace all the marinized parts on the diesel.  He patiently explained that while the diesel itself will probably run forever, marinized parts wear out.  His recommendation was to replace the marinized parts with new ones and rebuild the old ones as spares to take with us.  Seems like a good plan, but there are a few issues.

In and Out of Marinas Requires a Reliable Diesel, Shelter Bay Marina, Panama

In and Out of Marinas Requires a Reliable Diesel, Shelter Bay Marina, Panama

First, we still need the mechanic’s manual… for a diesel manufacturer that’s been out of business and is French, not US.  The out of business problem also impacts getting marinized parts.  Diesel Don recommends I get online and start researching and see what I can find.  Talk about a challenging research project, thank goodness for the internet!  Days later, I finally locate a place in Ft Lauderdale that could still get original parts that were, for the moment, housed in a warehouse located somewhere in France and yes, there is a mechanic’s and a parts manual available.  We bought the manuals as well as as many of the marinized parts as we could locate and had them shipped to the US.  It took awhile, but we were celebrating when they finally arrived!   SUCCESS, one step at a time!

Don started the process of replacing the marinized parts – including the salt water pump, the thermostat, exhaust elbow, all zincs, glo plugs, fuel injectors, fuel filters, installed an additional Racor fuel filter and added a gauge to show the filter’s status (red means CHANGE the filter),

At the time we couldn’t get the part for a new heat exchanger, so it received a thorough cleaning … or at least the best it could be.  He also cleaned up the exhaust elbow — letting it soak in muriatic acid.

Several years later, participating in the cruising online forums paid off HUGE when an online acquaintenance on the West Coast e-mailed to say they were repowering their Passport 37 (same Nanni Kubota as ours) and did we want to buy a big box of spare parts?   We jumped at the opportunity and as a result have a mixed bag of rebuilt and brand new marinized parts in our spare parts selection.  And it’s come in handy more than once – like replacing the salt water pump in Port Royal, Roatan.

Tricky Reef Entrance in San Pedro Belize Requires a Reliable Diesel

Tricky Reef Entrance in San Pedro Belize Requires a Reliable Diesel

Next … Alternator Agony

Are you haggling with your diesel?  Tell us what you did to extend its life. Leave a comment!  THX!  J

P.S.  If you have an older Nanni Kubota diesel in your boat and are looking for parts, we’ve had good luck with Waterway Power Center in Annapolis, MD.  E-mail parts@waterwaypowercenter.com.  Good Luck!





  1. Nice post, That`s really great information…!!!

Speak Your Mind