I believe I have posted here on this forum, forgive me if it was my "other" forum, about the difficulty of surveying and repairing Gardner engines. While they are still probably arguably the most stout engine ever, service and parts are near impossible.
I would tend to disagree with Judy on this point having been a Gardner owner. Parts are available world wide. especially from Australia, UK. These are new parts and price is not out of this world. And she is right the best marine engine ever built.
The Fiddler boats were built by one couple. The fit out is pretty good, they handle well from all accounts and amazingly have a very efficient hull form as they are usually powered by a Gardner 6LXB but still do their 8 knots and burn about 14 lt/hour.
As a current Gardner 6LXB owner/restorer my experiences match what Tidahapah just said about parts being readily available worldwide and reasonably priced so I just wanted to chime in here quickly to add to those comments.
Michael Harrison who owns and runs Gardner Marine Diesel in Canterbury England is my go to source for both parts and expert advise and I can not speak highly enough of Michael and his crew at GMD. Michael's dad spent most of his professional life working for the original Gardner company and when they went out of business he bought all the remaining inventory, equipment and machines. I've been able visit GMD several times now and would say that GMD is in many ways the "new" version of carrying on the original Gardner Co.
I purchased my original 6LXB when GMD took it in as a trade on a tug in the Thames that was repowering in a refit for a new role and they exchanged the 6LXB for an 8LXB which GMD had also rebuilt for them.
I have completely rebuilt the original engine replacing pretty much every part in it with brand new parts from GMD, other than the major castings of the heads, cylinder block, crankcase and oil sump. This included pressing in new dry liners and boring them out, new pistons, rings, valves, every bearing, gaskets, lift pump, etc. etc. so this is as close to a "new" engine as I think you can get. I keep pretty good records and my total costs for this engine came out to about the same as a new JD 6068 which I see as a very good value for what I believe will be a much longer lasting and dependable engine in our new boat mv Möbius.
A Gardner is clearly NOT the best choice for many/most boats but is definately the Goldilocks just right, just for us single main engine given use case and type of global cruising we do. Might be of interest to some that the Gardner is coupled to a Nogva HC168 servo gearbox turning our 1m OD 4 blade CPP prop which, counter to popular opinion, we found to be about the same price as fitting a standard transmission + fixed prop of equal quality, and the CPPP allows us to dial in the Goldilocks engine load for any SOG we wish.
My experiences with our Gardner similarly refute any notion that these engines are "difficult to assess or work on". Hard to find any diesel engine that is more simple and basic, which is part of what attracts me to them in the first place. Other than the 24V starter and the two massive Electrodyn alternators I'm driving with the Gardner, once started there isn't an electron to be found on this engine; no glow plugs, no electronics, even the gauges for oil temp + pressure and water temp are all simple direct reading thermometers or mechanical oil pressure gauges. Heck, I've even adapted one of the Gardner hand crank systems that was an option and I can hand start this engine if the starter should ever not be working. All normally aspirated so no turbo, fully mechanical fuel injection with priming levers, zero pressure fresh water cooling, all external copper oil lubrication pipeworks, etc. etc.
I am not trying to sell anyone on a Gardner simply showing how simple these engines are and thus how equally easy they are to work on and maintain. I can understand that many modern mechanics would find these Gardner engines "odd" and unfamiliar to the complex modern diesel engines they normally work on, but anyone who knows their way around a diesel engine will find a Gardner extremely easy to understand, test and work on.
If you are a glutton for punishment, there is WAY more info than you would ever want on the build of both the boat and the Gardner to be found in the weekly posts my wife and I have been doing for almost 4 years now of our design and build of our new eXtreme eXploration Passage Maker XPM78 at
https://mobius.world
I apologize for not being able to be contributing here on TF very much for the past few years as I spend pretty much much all my waking minutes (and many sleepy ones too) finishing the building and now commissioning of our new boat/home. Hopefully there is a light at the end of this long and winding tunnel in the coming months and I will be able to contribute more to the great discussions here on TF.