After three days in Xtapa, I was getting ready to go again.
The night before departure, I topped up all our fluids, both oil and coolant were down, since we had those repairs the days earlier. While they were topped up upon completion of those repairs, it takes running time for air to work out of the systems.
The rough seas and miserable pitching of the last few days seemed to really scour the fuel tank, so I ran the fuel polisher system (filtering fuel to take water and impurities out) on the starboard tank for 8 hours the day before. During the 8 hours, vacuum on the filter had increased from 4”, which is OK, but not great, to only 5”. Which is marginal. Since we were getting underway for another multiple day passage, I changed the fuel polisher filter, a Racor 900 filter system (Racor 2040 2-micron filters bought on Amazon for $12 each.
I usually don’t run the fuel polisher that often anymore. Unless needing to really top up the tanks, like leaving the Canaries for the Caribbean, I only put new fuel in one tank. Thus, I can isolate any issues. I then run the fuel polisher on the new fuel to check it out. Usually an hour; If the vacuum doesn’t change significantly, I turn it off. Sometimes the vacuum will even go down, when the new batch of fuel is better than what was in the tank.
Underway, I also always set the return to the same tank it is feeding from. Once, in prehistoric times, I set the return to the other tank as a means to transfer fuel. Of course, I forgot and ran out of fuel while running. I didn’t do that again.
But I did. This second time, I had inadvertently left both feeds and returns open. For whatever reason, my system tends to return more fuel to the port tank and less to the starboard tank if both returns are open. Thus, I emptied one tank. But this time, the engine did notice because I had also left the sight tubes open on top and bottom. The result was that although the starboard tank was empty, enough fuel was being returned, keeping the sight tube full, which was then fed back to the engine.
Had I closed the sight tube, the engine would suck air from the tank feed.
Lesson learned. Nowadays, besides feeding and returning to the same tank, I also keep the top of the sight tubes closed, so that fuel goes back to the tank. Otherwise, it defeats the purpose of using cooler fuel from the tank.
I like the Racor setup very much. Twin primary filters, Racor 500, in parallel, and a Racor 900 for fuel polishing and transfer. For a long-distance cruiser like Dauntless, it’s a mission critical system. Meaning don’t leave home without it. When underway, I don’t go into the engine room often, maybe only twice a day, once in the evening before my shower and bed and in the morning, after my early morning watch. (I usually wait until crew is awake, so I don’t wake them by opening engine room hatch, unless the night before I thought I may have an issue, then I check again as soon as I wake).
The parallel Racors really give me peace of mind. In the early days, when changing filters was more of an adventure than it should be, if I suspected a problem, I’d immediately switch filters to the new one and then monitor the new one for issues (water or clogging). But I didn’t have to deal with the filter just then. If in a benign environment, I may shut down the engine, but that is rare. Nowadays, I can change a filter in less than two minutes and that includes priming engine if need be. I installed an electric fuel pump just for that purpose. It makes doing any fuel related work so easy. I used to hate changing the engine mounted filters. I still have the scar on the back of my hand from spending days trying to prime engine (turned out to be a failed O ring had clogged fuel line to Injector pump). Nowadays, if I do switch filters while underway, I will change the old filter, so I always have a new one ready to go at an instant.
Nowadays, I almost never have an issue. But when I do, I need the fuel polisher now.
Like when we fueled up in Colon, Panama, waiting to transit the Panama Canal. It was a fuel barge, made even sketchier because they spent some time transferring fuel from a tug to the barge and then to my boat. Once I returned to our slip and ran the fuel polisher, it picked up a lot of water. Another reason to never run from both tanks at once. I knew I had a problem, but it was isolated in the port fuel tank. I also installed those plastic drains that can be opened by hand on all three Racor filters. So, in a situation like this, it made it particularly easy to run fuel polisher a while, when bowl is full of water, empty, run, repeat, until I decide to also change filter. I’ll usually do that at the end. Then give it a good run again to make sure it’s good to go.
I’ve had a few occasions, in which I just let the fuel polisher run and the vacuum gets to 22” to 24” of mercury (Hg). When that happens, I am ever more grateful that none of that crap got to engine or even primary filters.
Because the Racors are doing their job so well, I don’t change the engine mounted fuel filters very often. Maybe even on the order of 500 to 1000 hours. This interval has gotten longer and longer because even in the past when I did have some water in the primary filter, the secondary engine mounted filters had none.
You may think that that’s excessive. What’s the harm in changing the primary filters? In my first year or two, the primary filters were the cause of all sorts of issues from blocked fuel lines to air in the system. They are hard to reach, which introduces a greater possibility of error in replacement or even affecting some other nearby engine component.
The Ford Lehman SP135 engine and I have an agreement. I don’t mess with it and it does its’ thing, which is to never stop until so commanded. So, I am particularly careful working near the engine.
A couple of weeks later, this system would again save my bacon. I had carelessly kept running from the starboard tank, even after it went below the sight tube. I did have a reason, I wanted to see if I had really needed the expensive fuel I had added in some expensive place.
I’m in the pilot house and suddenly, I hear the pitch of the engine change. Remember, the Ford Lehman and I have an agreement. The engine pitch never changes. So, in seconds I had the hatch open and was down in front of the engine by the Racors. I instantly switched filters, then took the time to look around. The engine was starting to surge now (up and down in rpms). I looked at the feed tank and saw no fuel in the sight tube. Now the sight tube is still about 20 gallons above the feed line. I open the port tank feed and return and close the starboard feed and return.
Surge continues. I ask Larry to give it some throttle. No change. Throttle back to just above idle. I turn on the electric fuel pump used to prime filters. Add throttle. In about 5 seconds that seems like 5 minutes, the engine smooths out. I wait another minute and turn off electric fuel pump and carefully adjust valves that put electric fuel pump into main fuel line. (otherwise, when first installed, the fuel pump just pump fuel around in a circle, with out the need to go to the engine. Under normal setting this fuel pump is isolated in a parallel loop and the engine uses gravity feed and it’s lift pump).
From first change of engine pitch to running normally again took less than 60 seconds.
My Sp135 was good to go again.