Generator Working Again - at last

Following the failure of the Mastervolt genset during our Scottish trip, when we returned to base I set about further investigating the problem.

The generator had worked faultlessly until that fateful day when it fired up and then stopped, pumping what I thought at the time was smoke into the engine room. My preliminary investigation found the insulation on the top of the DDC (Digital Diesel Control) box - the electrical gubbins that controls the generator - had partially melted but I could see no other signs of damage or what might have caused the problem. Access to the LHS of the generator is tight and the sound shield further restricts access. However, there is a panel in the third cabin which allows sight of that side of the genset. On removal, this is what I saw:

In the centre of the picture you can just make out where the exhaust elbow has come away from the exhaust manifold. The sound shield, on the right, is resting again the wall of the engine room and needed to be removed; however, the frame that holds the shield in place prevented the shield's removal.

This is a view from the top of the generator looking down on the detached exhaust elbow. In order to gain better access I removed the front and top of the sound shield frame which facilitated full removal of the sound shield. Result: much better access. I also removed the engine bay vent ducting - a large flexible pipe that sits above the generator - and the expansion tank. Access was now good and the offending parts could readily be removed.

It transpired that the 4 studs that should have been attached to the exhaust manifold had pulled out of the alloy flange. It appeared they had only been inserted to the depth of 3 screw threads and, over time, as corrosion took its toll the alloy of the manifold could no longer support the elbow. The local marine engineers milled the flange flat to provide a suitable surface for the gasket and fitted new studs. The result is shown below.

Unfortunately, this work was not completed before the departure date for our trip to Holland (blog to follow) so once again I set off without a generator. The Dutch still have Mastervolt dealerships whereas the UK doesn't. Legacy equipment is now supported by Fisher Panda and trying to get someone local who was knowledgeable about the generator was becoming irksome. Although I could see no visual damage to the wiring I asked some Mastervolt engineers to look over the generator whilst we were in Amsterdam. What I had feared was smoke resulting from burnt wiring turned out to be a mixture of exhaust gas and the molten DDC insulation.  The Mastervolt folks confirmed this and gave the generator a clean bill of health. Or at least as best they could without seeing it run! On return to the UK, the now renovated parts were replaced and it was time to give it a test run. 

All renovated and back together

The generator fired up without hesitation but the output voltage, at 204V, was lower than the 210V minimum required for the set. A bit of investigative work pointed to the capacitor being faulty. The capacitors were tucked away in the depths of the DDC but could be accessed without too much trouble. 

The 2 old capacitors 

I sources new capacitors on line and fitted them. You can just see them in the second picture below tucked into the bowls of the DDC.

Time for a test run. She fired up and produced a very health 224V. Success. I have since run the generator several times and she is back to working like a dream.

As an aside, I thought I'd replace the air filter (below) whilst I had the opportunity. I tried Fisher Panda but I'm still awaiting a price and availability! I sourced it online as a Mastervolt spare and it came in at 53 Euros (plus tax and delivery). I found the exact same filter sold as a car spare for £5 (plus tax and delivery). A good example of the mark up applied to marine goods! Happy days.