Mid-winter, on one of my periodical visits to the boat, I was blown away with the smell of diesel fuel when I slid the hatch open. I chalked this up to the new cover not giving the boat as much ventilation as it used to have, but I really wasn’t fooling myself. In the back of my head I’ve been wondering why the boat smells worse this year then last?
When doing my spring commissioning I discovered a drop of fuel on one of the fuel filters. I didn’t have time to look at it until now. I was partly motivated as we are are on day 10 ( I’ve lost track) of a trip to the 1000 islands. The girls still crawl into our bed some nights and last night I was squished up against the back bulkhead, getting strong wafts of diesel. That was enough to motivate me this morning to see if I can stop the leak.Fearing that the hose was getting a split at the end of the barb, like the fresh water intake did on the Jabsco, I started there. Sure enough there was a drop on fuel on the bottom of the clamp. I didn’t want to remove the hose and bleed, so I trimmed a quarter inch in-place and slide the hose down the barb, putting the clamp on fresh hose. (I didn’t see any cracks). After I did that I discovered that there was a drop on the hex plug next to it. It was very loose so I tightened it up. Not sure if it is a stress crack, overtightened, or loose?
I then went over the engine looking for any drops or drips or loose connections. I discovered that the final fuel filter on the Yanmar has two loose banjo bolts, they could rock back and forth like a toggle switch, sort of notching. Clearly loose. I nipped these up. Also present was a bit of fuel on the top bolts on the filter. I haven’t had these off but perhaps the previous owner did. Perhaps they are copper washers needing annealing?
Finally I noticed that one of the engine mounting bolts was very loose, the nut had worked up about a half inch. Snugged that down too.
Hopefully that will stop the smell. The engine is very tight, no oils leaks, just belt dust. It is easy to see issues when things are so clean, but it does remind me that I need to go over the engine every now and then, especially after long periods of use.
Nov 9, 2015 – When winterizing I looked to see if there were any leaks or drips. The top screws on the engine fuel filter are a tiny bit weepy, perhaps new washers are in order.
A new leak is one of the shut off valves near the two redundant filters. The leak is dripping off the valve itself, not the hoses/clamps. I can see the word water on the valve and the handle is red, so it looks like a standard ball valve from the hardware store. I will have to check to see if it is rated for Water Oli and Gas WOG. Perhaps the fuel has degraded the seals?
A quick search reveals that diesel fuel valves have “Polytetrafluoroethylene seats and seals provide positive sealing with easy opening and closing. 600 psi water, oil or fuel.”
The tractor people say it is ok to use water rated valves on low/no pressure applications for fuel and hydraulics, but perhaps they are looking at it from a pressure