Engine Work

It looks like the problem with the engine has been identified and the front head and injector have been taken away for assement and repair.

After reading the SABB manual a couple of times I realized that what I had thought was the mixer was the manifold (or what SABB calls the "silencer"). The mixer was a tube bolted to the manifold and connected to the exhaust hose. Removing this was a much easier job than removing the manifold.

It took me about 30 minutes to remove the mixer and we could find no blockager or buildup in it. I used a long screw driver and thick wire cabling to ream it out then filled it with water and agitated it. No serious material came out and I could see daylight by looking through one end of it and could see no problem. I looked into the manifold and saw no obvious problem. I then blew into the exhaust hose (That's right, my mouth is a tool for blowing down greasy hoses as it is for tasting bilge water, and after the blow effort I had the benefit a darker mustache.) and though I felt some resistance I eventually broke through and could hear noise from the exhaust outlet at the stern. I think that the back pressure was caused by the fact that the exhaust gas passes through water in the muffler. We then tried several times to start the engine without the mixer in place and it still would not start. To us this eliminated a blockage in the exhaust system as the cause of the engine problem.

I hate phoning up a professional during a weekend, much less Easter Sunday morning, but I forced myself to phone Colin because I needed to know whether I should restore the mixer or go on to another step. I telephoned Colin expecting either no answer or a justified response to bugger off. He answered and I explained what I had found. He then suggested that I remove the injectors (gulp!).

I agreed to have a go at it then I mentioned that I could see evidence of salt water dribbling from the front head gasket, and that section the gasket seemed a bit eaten away. To Colin this was a game changer. To my surprise he told me that he was about to leave the shop and that he would be at one of the boat ramps in 10 minutes where I could pick him up and bring him to the boat. Ten minutes later I met Colin and his small boat-wise bitch (literally a dog, folks) and we piled in the Zodiac and headed for Pachuca.

Colin quickly established that the rear cylinder was OK but the front cylinder was not OK. After various tests and removing bits of the engine it came down to his demonstrating to me that when Arnold hit the starter and the engine turned over we could see vapor from the front cylinder coming back at us indicating that there was a leaky valve, probably the inlet. He took the head off and water started to dribble out and he commented that this was not good.

His analysis is thus: The front cylinder has a valve problem which means that it cannot reach the compression required to ignite the diesel fuel. The engine was not able to start on only back cylinder. When I let the engine breath WD40 I was (a) lowering the ignition pressure and (b) probably helping to seal the valve somewhat. Once the engine got warm it ran better, sort of, but the excess carbon was the result of lots of fuel going in but insufficient combustion in the front cylinder.

Colin took away the head and the injector. The faulty front head is the original rear head that was moved to the front cylinder so that the stronger rear cylinder could take the new head that was installed in Port Townsend. He will have the head and valves worked over and he will have the injector checked. If the front injector is OK he won't check the back one; otherwise he will have the back one checked too. Arnold has suggested that I carry a spare injector and I will discuss this with Colin. The machine shop he works with must be pretty good because he says that they can make new valves for the engine if they have to. He told me that the work should be completed in about 3 days. That's not saying that the engine will be working in 3 days, but I am much more confident that I will leave La Paz with a well-functioning engine.

After lunch Arnold made a short visit to the marina to get fresh water and I tidied up the boat. I then went for a swim and had a pretty good cockpit bath using some of the fresh water that Arnold had brought back. We then enjoyed the luxury of ice cold beer on Pachuca that had cost us only about $1 per can.

The photos are of the engine with its front head removed, the mixer, and my beautifull SABB engine before we defiled it with our wrenches.