Replacement of a marine engine on a Moody 346

Author: Graham Collins

Replacement of Thornycroft T80D engine with a Solé MINI-44 on a Moody 346

Engine supplied by Engines Plus Ltd.
Installed once out of the water at Marchwood Yacht Club in Southampton

marine engine replacement on a moody

Having decided to replace my aging Thornycroft T80D, I was torn between the Beta 35 and the Solé Diesel Mini.  So, I visited both stands at the Southampton Boat Show.  As expected, both companies were extremely helpful and I left being no nearer a decision.

The one nagging issue with going the Solé route was the fact that they didn’t have anything around the same 35HP as the existing T80D.  Their range jumped from 32HP to 42HP.  I, therefore, posted a thread on the MOA website seeking opinions on going to a 42HP.  Unsurprisingly, half thought it was a good idea and half felt it was too big an engine.

In the end, I went with the Solé Mini 44 (in fact 42HP), as it was similar to the old T80D being based on a Mitsubishi engine.  Our extremely useful and knowledgeable Diesel engineer at Marchwood Yacht Club also felt this would be a good choice.  As I was going to rely heavily on his support and help during this project, I went with his advice and plumped for the Mini 44 as the replacement.

We Moody 346 owners are very fortunate to have such terrific access to our engines and also being able to remove the cockpit floor to enable the engine to be lifted straight out of the cockpit.  This made the whole project an awful lot easier.  Also, my gearbox had broken, so I could remove this and discard it making more room for the engine removal.  I did, however, intend to sell the old engine as a working unit, so I was careful not to disturb too much during the removal process.

Firstly, having disconnected the mains power, I removed the batteries completely from the engine bay.  I then disconnected all the obvious water and fuel hoses and the prop shaft.  I then removed the gearbox and taped over the whole left behind in the bell housing.

As the new engine comes complete with a new instrument panel and wiring loom, I removed the earth wires, the old wiring loom and instrument panel.  Again, I was somewhat fortunate, as I was going to have to mark up all the individual wires to say where they came from so the new owner could re-wire it at the other end.  Luckily, a company who specializes in refurbishing engines bought it and said they didn’t need it to be marked as they would probably make up their own new loom anyway.

Removing the exhaust hose proved to be very difficult as it had become quite inflexible over the years.  I, therefore, unbolted the exhaust elbow and removed the hose later once the engine was out of the way.  At that point, I also removed the exhaust mixing pot.

 replacement marine engine on a moody sailboat

In order to remove the cockpit floor I had to disconnect the steering cable from inside the steering pedestal, remove the pedestal and the 2 legs either side.  On the starboard side, the leg houses the Morse controls which operate the gearbox and engine throttle.  Both of these were removed at the engine end and the leg lifted out as a complete unit.

Replacement of a marine engine on a Moody 346

Finally, the floor was lifted and I got my first view of the engine from above.

Replacement of a marine engine on a Moody 346

You can see from the next photo how the T80D was fixed to the engine bed.  The engine bed has an encapsulated metal bar within it.  This is tapped with M10 holes to take the mounting bolts.  There seemed to be very little difference between the specifications of the T80D and the Solé Mini44 so I was hopeful for a reasonably easy swap out.  Sadly, that wasn’t the case.  More on this later.

Replacement of a marine engine on a Moody 346

A fortunate part of being at Marchwood Yacht Club is that it is a proper boat yard, owned and run by the members.  A number of the members are also very experienced engineers and there is nothing they can’t make or fix.  So I just had to ask for help and they were there through the project.  To get the engine out, they put a metal shoe over the forks to the fork truck which had a long boom on it and a hook at the end.  To this, we added a chain block and lifting strop.  The strop was shackled to the lifting eyes on the engine.  The initial part of the lift out of the engine bay was done via the chain block for greater control. Once it was clear of the cockpit, the fork truck took over and, within 30 minutes, it had been lifted clear and put on a pallet on the ground.  It was then bolted to the pallet and a hauler collected it the next day for onward delivery to the new owner.

I had arranged a 2-week gap between the engine coming out and the new one being delivered so that I could paint and tidy up the engine bay.  You can see the before and after photos below.

Replacement of a marine engine on a Moody 346

Replacement of a marine engine on a Moody 346

I used Danbolin bilge paint to achieve this transformation.

As I mentioned, the engine specifications were similar.  The width between the engine mounts was within 3mm but the Solé was longer and had larger feet.  There was also a larger drop in the gearbox shaft compared with the engine.  The old feet were sitting on spacers so, overall, I was expecting to put new spacers under the feet, drill and tap new holes for the engine mounts and off we go.  However, when we dropped the new engine in, it was immediately obvious that it was way too low as the bell housing hit the engine bay floor before the feet were anywhere near the engine bed.  After a lot of head-scratching and puzzling as to how I had got the process so wrong, it dawned on me what had happened.  The T80D had upside down, “L” shaped brackets attached to the engine block which the feet were bolted through.  What the previous installer had done was to invert these brackets thereby raising the engine height.

It was clear at this point that there would be much lifting in and out of the engine before we got this solved.  However, it wouldn’t be necessary to lift it completely out of the boat, just lift it high enough to work.  So, to free up the fork truck, I put a long metal square box section across the cockpit coaming and hung the chain block off this.  I could now maneuver the engine to my heart’s content without tying up the yard’s precious resources.  I erected my cockpit tent over this so it didn’t matter what the weather was going to throw at me.

I used lengths of wood and spacers of varying sizes and kept lowering the engine onto these until I hit upon the correct amount of spacing needed.  The marvelous club members came to my rescue again and made the box sections below.   These were 100mm wide and 60mm high mild steel.

Replacement of a marine engine on a Moody 346

Initially, I made templates so the bottom of the box sections could have holes drilled to match the old engine bed’s M10 tapped holes.  Access gaps were cut away on the inside of the sections to allow a ratchet ring spanner to be used to bolt the new section onto the engine beds.  The engine was then lowered into place and the feet adjusted to get an exact alignment with the propeller shaft and the gearbox flange.  The box sections were then marked where the feet needed to bolted down and the whole thing removed again.  New holes were made and deep inserts welded in place which was then tapped M10 again to take the new engine mounts.  You can just see the deep inserts through the access gaps above.  All of this was done over 2 days by the clever chaps in the yard.

Finally, I painted them, inside and out with Red Oxide paint.  I then painted the outside with spray paint, supplied by Engines Plus Ltd., which matched the rest of the engine.

The whole lot was then bolted down again, having put a bed of Sikaflex under the new box sections.  The engine was then bolted to this and re-aligned with the propellor shaft having now fitted a new R&D coupling.

Replacement of a marine engine on a Moody 346

Replacement of a marine engine on a Moody 346

Replacement of a marine engine on a Moody 346

It was now a case of replacing all the old water and fuel hoses with new ones, properly routed around the engine bay, and fitting the new panel.  The pre-wired wiring looms made this very easy, just connect the 2 multi-plugs together.


The engine has now been fired up and proved to work.  The remaining problem is that the throttle Morse control used to be clamped to a bracket at the rear of the engine and pulled the throttle open.  The new fitting is at the front of the engine so as to push the throttle open.  I will, therefore, need to reverse the mechanism in the cockpit leg and re-route the cable, maybe needing to buy a longer one.

Whilst doing all the above, I took the opportunity to fit a new cutlass bearing in the “P” bracket and a new PSS seal to the inboard end of the propeller shaft.

I look forward to getting back in the water to see how it all performs and would like to thank all those who provided the much-needed help to ensure a successful project.

Replacement of a marine engine on a Moody 346

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