Boat projects

We travelled directly from Rodrigues to Reunion, skipping Mauritius, mainly to spend more time enjoying Reunion’s incredible natural beauty. But we’ve also been taking advantage of being on a little less of a tight schedule to complete a few boat projects.

Trip highlights from October 6th follow. Click any image for a larger view, or click the position to view the location on a map. And a live map of our current route and most recent log entries always is available at

Valve adjustment

The valves on our John Deere 6068AFM75 require adjustment every 2,000 hours. We last did this in New Zealand not even two years ago but it’s due again.
Drive belt

Checking the main engine drive belt, accessory, and idler bearings. James is feeling for rough spots or noise when rotated, or free play.
Pressure test

We pressure-test the cooling system every 2,000 hours. It’s one of those jobs that seems like a waste, as we never find a problem. But this time we did—the pressure test indicated a very slow leak.
Coolant leak

We found a coolant leak where the hoses connect to the main engine keel cooler. The installed clamps were too big and had bottomed out rather than clamping with full force. James replaced the two clamps with four high-quality clamps of the right size and stopped the leak. The corrosion visible at the keel cooler is from a small saltwater leak that will require hauling the boat and removing the keel cooler to properly repair. Ironically, the leak showed up just after our last haulout in New Zealand. We’ve temporarily sealed the leak with epoxy, which does work, but it appears to cause some surface corrosion.
Oil leak

We also investigated a small oil leak at the main engine power take-off cover. The sealing o-ring was hardened and cracked. We don’t carry a spare, but successfully sealed it up with Permatex orange and will get two spare o-rings on our next Deere parts order.

Time to change the bag on the central vacuum.

Show locations on map Click the travel log icon on the left to see these locations on a map, with the complete log of our cruise.

On the map page, clicking on a camera or text icon will display a picture and/or log entry for that location, and clicking on the smaller icons along the route will display latitude, longitude and other navigation data for that location. And a live map of our current route and most recent log entries always is available at


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7 comments on “Boat projects
  1. Alex Benson says:

    Hi J & J: Wondering how the main engine drive belt is holding up with both those BIG alternators? Have you changed the belt it out? If so how often?

    Great blog and photos. Alex

    • Great question and a timely one since I just finished checking the belt. Belt and idler pully failure can lead to rapid engine overheat so we check ours every year. I look at each bearing and spin looking for noise or rough spots. On our engines, in 6,400 hours we replaced one idler. On our previous engines (Cummins B-Series) in 4,100 hours we never had to replace any of them. The Cummins would wear out belts every 3 years or so. The Deere seems to be super kind on the belts. Perhaps just accurate routing and good heavy duty brackets. We have only changed one belt in 6,400 hours and that one was in pretty good shape.

      The “trick” is to use serpentine belts. They can take incredibly high loads and just run for ever. These are roughly inch wide belts where the back is smooth and the other side that engages in the pullys have small groves. These belts have a spring tensioner maintaining tension, they are wonderful to work on, and they can drive heavy loads without issue. On our engine, we have two alternators each capable of 4.5kw and the belt life is unaffected.

      I’ve never liked V-belts but you can drive big alternators with V-belts. You just need to have them paired and they need to be good quality belts well of matched size and well adjusted. If you have a choice, go serpentine.

      • Alex Benson says:

        Great info! We have 4950 hours on our Cummins QSL with no belt issues, but reverse mounted the 2nd alternator with double-V’s off a pulley. Just amazed to see both Dirona’s BIG alternators on the serpentine belt. So I guess when installing the 2nd alternator, you just get a longer serpentine. Did you have just the serpentine on the previous Dirona?

        One other question regarding Dirona’s hydraulics. As I recall, Dirona needs an auxiliary engine to power the thrusters? Wondering if there is a way to use a different power take off the John Deere main to drive the thrusters?

        I continue to learn a bunch from you guys. Thanks for sharing.


        • Yes, we head serpentine beltes on our two 5.9 liter B-series Cummins. We put 4,100 hours on that pair of engines and just loved them. They are really solid and reliabley work horses.

          When adding the alternator to the Deere, Cascade Engine in Seattle (the supplier) just changed an idler, added an idler, and installed a longer belt. It’s a pretty nicely engineered belt run and the serpentine belt can drive high loads without issue or excess wear. We have only changed one belt in 6 years and more than 6,000 operating hours.

          Good question on the hydraulics pumps. We have identical hydraulic pumps on the main engine and the Wing. Both are 45cc Rexroth pumps and both are capable of running the entire system. Underway the main runs the stabilizers. When at the dock, anchoring, in in close quarters, the wing runs the thrusters and windlass. Technically both engines can run eiher but in close quarters the main engine is at idle so it lacks the power to run the hydraulics at full out put. So we use the Wing in those conditions. But, we have redundancy and the main will do the job even in close quarters if needed.

          A few of advantages of depending upon the wing: 1) it actually gets used and, by far the biggest killer of wing engines lack of use, 2) the wing is running and ready immiediatly if the main fails, and 3) if the main fails and we need to limp home on the wing, it can both drive the boats and also keep the stabilizers operating. It’s much easier to fix things in a stable boat. The Deere is reliable and has never skipped a beat in 6,551 hours but when operating a thousand miles from help, it’s good to have redundancy.

  2. steve says:

    Hi J&J
    James what is the procedure for adjusting the valves in your engine? It looks a specialist job to my untrained eyes.

    • Valve adjustment is surprisingly easy Steve. The main is the a 6 cylinder 4 valve per cylinder engine but it’s only done every 2,000 hours. The wing is a 4 cyl 2 valve head, that I do every 750 hours and the generator is a 3 cylinder variant of the same engine as the wing and it gets done every 1,000 hours. The procedure is fairly simple for all of them and is described on a single manual page for each. Put theh engine at top dead center (TDC)#1 cylinder and adjust half the vales (the manual lists which ones) and then rotate the engin exactly 360 degrees back to TDC and adjust the other half. Lossen the lock nut and wiht an allen key in the valve ajduster, ajust the clearance such that a feeler guage of the appropriate size for your engine just barely fits with noticable drag between the rocker and valve (or bridge if a 4 valve engine). The feeler guage is just a strip of metal of very accurate thickness. The thickness is usually different for Intake and Exhaust valves and is specified by the manufacture.

      It’s a fairly easy under 2 hour job for a 4 valve 6 cylinder.

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