Posted on February 27, 2016
Engine Part 2: Winterizing Mistakes.
After fixing the stuffing box/coupler and fuel supply system, Milou’s diesel motor had a pretty uneventful first season. This was back in the summer of 2014 when we had managed, by Deb’s wiliness, to secure a very good deal on a fancy marina slip.
The engine spent about four hours crossing to Little Sturgeon Bay, maybe an additional 15 hours over the summer motoring in and out of our new marina and then again the four hours back to Hi Seas Marina in Oconto. The motor ran like a top.
I had yet to change the oil–the most basic of all routine maintenance. Every time I went to the boat I was feeling guilty about the unknown age of the oil sitting in the motor. I had meant to change it in the spring, honestly I did. But then a lot of other projects came up, and as crazy as it seems, I simply could not find the time to change the dang oil. I needed to rig the mast, remove and get the rudder repaired, sand and seal the rusting spots on the keel, install the windlass, and pull off all of the items that froze and broke thanks to the not-so-great “winterizing” job performed by the Texas yard where we bought Milou.
That summer, every time I went to the boat I brought the oil and the filter. And still it never got done. Fall of 2014, the boat was hauled out at Hi Seas marina. We had a small issue with the mast. But that would have to wait; the boat still needed to be winterized.
I built a frame, sturdier than the one I made the year before. No flimsy line strung between 2x4s: a solid wooden 2×4 ridge pole supported by the modified stands (no longer needed) I had built to hold the mast, and then I covered Milou with the o-so-chic classic blue tarp. The Perkins 4108 has a built-in, hand-operated oil sump pump. It has a T handle, and after 15 – 20 pumps it removed about three and a half of the four quarts of oil that the engine holds.
For some reason the oil filter is mounted upside down; when you remove it, all of the oil trapped inside the filter runs down the side of the motor and into the bilge. Luckily, I had some oil absorbing mats in place to catch the mess. And now I know about the little drain screw in the oil filter housing that lets you drain the trapped oil into a small paper cup before you unscrew the filter.
Now with the oil and oil filter changed the only routine maintenance item for which I had no record of the last service was the primary fuel filter (well that and the transmission oil, which I have yet to change–it looks good).
Changing the primary filter is a pretty simple affair. You unscrew the retaining bolt, spill diesel all over the place, throw out the old filter, put in the new filter–making sure all of the various o-rings and gaskets are in the correct position–and retighten the retaining bolt. Then–before you run the motor–you open the vent screw on top of the filter housing and manually prime the system until the filter is full of diesel and there in no air at all in the system.
I didn’t talk about it in the last post, but the Perkins 4108 is a mechanically fuel injected motor. Unlike a new VW diesel (are they still making them?), which a has computer-controlled electronic injectors and a self priming fuel circuit, the 4108 relies on a Swiss-watch-like complex mechanical fuel pump to deliver pressurized fuel to the mechanical injectors. These mechanical injectors rely on a high pressure shock wave traveling through the fuel to pop (or jerk) them open so they can spray precisely the correct amount of atomized diesel into each cylinder. Here is the problem: a gas is way more compressible then a liquid. When air gets in the fuel system the shock wave created by the fuel pump travels through the fuel until it hits an air bubble. The compressible air bubble is a shock absorber and stops the shock wave so the injector can not jerk open (these are commonly referred to as jerk injectors). The VW doesn’t care; the high pressure fuel pump circulates the fuel and any big air pockets are sent back to the fuel tank, and if a little air gets to the injector the computer still opens it up (it doesn’t know)–for one cycle one cylinder is just slightly lean. In the same situation, the 4108 stops cold and stares at you until you fix the problem.
It was a warm for October day when I changed the fuel filter. Before I did the mechanical work, I did some temperature-dependent fiberglass work, leveling out the interior of the transom where the radar arch backing plates go. By the time I got to the engine work it was dark, the temperature had dropped, and I was cold, tired and hungry. So naturally I switched out the fuel filter…
The last step of winterizing is to get all of the water out of the motor. I removed the drain plugs from either side of the block and the water barely trickled out. I fished around in the drain holes with the end of a plastic zip tie and got the water to move slightly better. The cooling passages of the engine were pretty clogged up with 30 years of built up scale from direct cooling with Lake Texoma water. I replaced the drain plugs, removed the thermostat, removed the raw water intake hose from the seacock and stuck it in a bucket with four gallons of pink RV antifreeze.
I went up to the cockpit to fire up the motor and I got a two second run, then it stalled. I tried again and it coughed once and was done. Oh crap, I never primed the filter.
This is when I learned how to bleed the fuel system.
Bleeding the fuel system involves opening a series of small, well camouflaged, very hard to find bleeder screws in a precise order and priming the fuel lever at each screw until all of the air bubbles are out before moving on the the next screw. If you miss one you have to go back and get it before the motor will run. Six hours, and multiple starting attempts later, I got the motor running. I ran the engine until solid pink antifreeze was coming out of the exhaust. Winterized.
Last summer, after getting the motor hot (closed cooling with not enough antifreeze) I created a vapor lock situation. That time it took me 15 minutes to bleed the fuel system.
Next up in Engine part 3: Converting to closed cooling.