Newbie resurrection

[StevenMac]

Another update. After a few short runs with the motor, I drove the boat for several hours from the marina where I bought to another marina where I'll do the rest of the work. The motor seemed to do fine. I stopped by there yesterday, though, and a gasoline smell was pervasive throughout the cabin. I spent a couple hours there washing the deck, with a box fan in the companionway and the blower running the whole time. After I got home, I could smell gas in my sweater. The thing is, when I inspect the connections, I don't see any leaks. I touched the fittings then smelled my finger and got nothing. Is it possible for a fuel connection to leak just fumes, but not liquid?

[TimBSmith]

Vapor vs Fluid

The short answer is yes. For example, you have a vent on your gasoline tank. It plays a role bleeding off gasoline vapors and with tank pressure functions for gravity and pumped fuel. There may also be an anti-siphon valve. You could also have a vapor leak on a fuel line that you notice before you notice liquid fuel. I WOULD ELIMINATE ANY IGNITION SOURCE UNTIL I ISOLATED THE LEAK VAPOR OR LIQUID. CONSTANT HIGH VOLUME VENTILATION will speed evaporation. In addition to checking gasoline condition issues, I have thought about buying swabs like this to check fuel lines for leaks, especially connector sites, https://www.amazon.com/Gas-Test-Swab.../dp/B01N5XEZ7M

Wonder if anyone here has tried something like this. Or a cheaper version. Best wishes. Your story is coming along wonderfully. And this setback is another learning opportunity.

[StevenMac]

Thanks Tim. Today I started working on really cleaning the bilge. It assuredly emits a fuel odor, which became more apparent once I began agitating the water. So, I decided I won't be able to determine if there's a fuel leak occurring now until I rid the bilge of any remnant fuel. I figure that when I ran the fan and blower for a good while and then started the engine, I'd aired out any fumes so it was fine, but they might accumulate while the cabin was closed up even without the introduction of new leaking fuel. So I put in bilge soap and filled it up with water, then emptied it (into a bucket!) an hour later. Filled it again with the soap and water, and left it to sit overnight. If I can get it to where there's no describable gasoline smell from bilge, I'll have a much better idea whether I have a leak in the lines. That sensible?

[Dave Neptune]

More

While you have been checking lines have you checked the tank? Often way overlooked are the lines out of the tank that do not feed the carb.

First check for a drip at the low point of the bottom of the fuel tank. Both the "filler hose" and the "vent hose" have probably never been changed out which is good practice for safety. If there cracked replace them.

Dave Neptune

[TimBSmith]

One other thought...

You know you have a fuel leak. So that is information.

I have learned here to go end-to-end just like you are doing. Tank, valves, connectors, filters, pressure gauge, carb, you got this. Any location of fluid flow. I have messed up and cross threaded the copper connectors, everything looks tight but the peened/flanged end of my copper tubing really is not tight inside the connector.

Keep the area vented, be sure to ventilate the space with new air volume, not simply circulate air in the space. You probably will find leak on inspection. No ignition sources until you find it (the leak).

If really baffling...

You can borrow a smoke machine and test lines. https://youtu.be/buszJ2jzvWU/

I doubt you will need to go through this subtle diagnostic trouble. The fuel problems on our engines seem to present like a brick bouncing off of the skull.

You got this.

[StevenMac]

After getting the bilge cleaned out and returning to the boat a couple of times, I haven't found any new fuel odors. I'll be out of town for a bit, but when I get back, I will connect the fuel lines with the inboard tank, and this time intend to coat all threaded fittings with permatext form-a-gasket 3, as I've learned that the uncertainty is quite unsettling. For example, coming back to the boat after doing a bunch of cleaning, I open it up and get hit with an odor, which I eventually recognize as Simple Green. But that's pretty strong, so could it be masking gas fumes...etc?

[sastanley]

The gas fumes sink, so the best way to detect them is to stick your nose in the bilge...however, they should also present themselves when opening the hatch if the boat's been closed up.