Reassembly and testing
The socket and breaker bar were used to tighten the injectors back up. I couldn’t find a torque value for the nut so tightened them up as hard as I could, using the same pressure as I did undoing them. Normally at this point I’d use a specialised hand pump and pressure gauge to check the injecting (or ‘breaking’) pressure, which is controlled by the shim and the spring. However, I don’t keep those tools on the boat in Portugal, so I decided to check my work by reinstalling the injectors and starting the engine. I’d have them properly calibrated later.
Reinserting injectors
Before refitting the injectors into the cylinder head I cleaned up the apertures with a piece of wooden dowel and some cloth. The copper sealing washers had come out with the injectors and had left a clean smooth seat in the head.
The injectors were smeared with lithium white grease to prevent corrosion and the copper washers on the tip of the injector were held in place by a smear of grease.
I made sure the stainless centralising collars were in place as well and the injector clamps and bolts were torqued up to 43Nm (32ft/lb).
The pipes and raw-water pump were refitted in the reverse order they came off.
After slackening the injector pipes to bleed the air out of the pipes and injectors, the engine started easily enough. It was a lot smoother and the hesitancy causing the vibration had gone. I warmed it up in gear tethered to the pontoon and then ran it in stages up to full throttle.
There was lots of smoke at first – the leaking injectors had caused incomplete combustion and allowed a build-up of soft carbon in the exhaust manifold area – but it soon settled down to a clear exhaust.
The new clean burning nozzles have solved that problem and now full wide open throttle is available without excess vibration or smoking.
I’m also now expecting a much reduced fuel consumption figure.