Carb Leak this Weekend!

[vabiker23518]

Last weekend, I commissioned MERLION with new spark plugs, drained old gas and Racor Filter. Started and ran fine. Used it this Saturday to ride down to Yorktown and returned, again no problems. At the slip, I managed to have a mooring line rap around the shaft and that stopped the motor. Turned the key off, got her moored, cleaned and left. Sunday, I returned and got the rope off the shaft. I opened the boat to check on things and found a strong smell of gas. Looked at the gauge, and saw approx 3 gallons of gas were missing from the tank...and was now in the bilge. Immediately secured the fuel valve at the tank. After getting the bilge clean, with a high pucker factor on my part, and airing it out, the gas smell is gone. I know I should ALWAYS secure the valve at the end of every sail day, but its buried up in the lazarette, and you know....
I have obtained a valve to put on the gas line and am thinking about between the Racor and the electric fuel pump. Is that a good location?
Also, what do you think caused the carb to leak. It is NOT coming from the fuel lines. They were all tight and dry. The carb was wet on the bottom. I assume the float and valve are stuck. Don't have time to take the carb out now as leaving on vacation for a week tomorrow, but would value your thoughts/ideas. I've had the boat 6 years and this is the first time this has happened. I have had the carb out and cleaned it 3 times with no issues. Could the sudden stoppage caused by stalling the engine caused the float and valve to stick open?

[Mo]

debris.

Yes, sounds like a bit of debris might have made it's way into the needle valve seat...or something along those line. Taking the carb off, dis-assemble and clean and blow everything out with air. Take care of the settings on the float and don't move it...should be fine to put back together and work well.

[Dave Neptune]

Stuck or sticky

vabiker, sound like some krud in the needle and seat holding the valve open, an easy but very important fix.
Did the engine seem to run like usual on the last running? Because if it was leaking while running it was probably way rich as the fuel leaking at that time should of been sucked up from the throat of the carb via the scavange tube.

Dave Neptune

[vabiker23518]

Thanks for Thoughts

No Dave, it was running very well...no issues at all. Had used very little gas Saturday...gage read right at 1/2 tank at end of day. Sunday, it was midway between 1/4 an 1/2 tank. I'm having trouble equating the sudden engine shutdown due to the mooring line around the shaft and then a leaking carburator...but seems too much of a coincidence!

[shibumi]

fuel leak

misery loves company this same thing happened to me last week. Boat had been running great. Went on a nice cruise to Catalina Island and back a couple weeks ago. Right before Memorial Day I could't get my engine to start. No fuel getting to the carburetor. My mechanic checked it out and said it was the fuel pump. Installed new fuel pump. Next day when I went on the boat I smelled gas. No leaks around where the work was done so I just figured he spilled some during the install and cleaned it up. A week later I came down and found a significant amount of fuel in my bilge just like you did. Not 3 gallons but about a half a gallon. My fuel tank shut off was off. Nasty. It appeared to be leaking from the area where the copper tubing goes from the bottom of the carburetor. Could have been dripping down there from the are of the spark arrestor however. Anyway i have removed the carburetor and am looking at the needle that contacts the float tanks. Although it appears to be clean I am going to put in a new one just to be safe. Don't know what else could cause this. I hope that's all it is. It's amazing to me this could happen. Very dangerous

[JOHN COOKSON]

Fuel tank higher than the carb and nothing in place to restrict the flow can and will get the siphon started.

TRUE GRIT

[CalebD]

Shaft wrap

I doubt that your shaft wrap had anything to do with the float needle getting stuck. Pure coincidence.

2 - 3 gallons of gasoline in your bilge sounds like quite a real 'pucker factor'. I've had some the same issue happen due to crud in our fuel tank and as a result we always shut off the fuel petcock when leaving the boat. Our fuel shutoff valve is between the tank and the Racor filter - which makes sense in case the Racor developed a leak.
If you are adding a second valve to your fuel line it may make less of a difference where you put it as long as there is a shutoff valve between the tank and first filter. If your second valve is easier to reach that may be more important.

[ndutton]

I had a similar experience some years ago. When full, the fuel level in both of my tanks is higher than the carburetor. The stop valve on each tank is a pain to access so lazy me counted on the carburetor float valve to hold back the tide. Big mistake.

After a single episode of gas in the bilge (one is all it takes) I added another stop valve immediately ahead of the carburetor. The handle is readily accessible without opening any compartment. Not a single issue since.

[zibadun]

This is on my short departure checklist
-close hatches, through hulls, fuel valve, check electrical panel,check docklines

i still miss something every now and then

i'm not even sure how to go about removing three gallons of gas from the bilge. I'm assuming it would trigger the bilge pump and create a big slick behind the boat that I would need to report. yikes.

[kiskadee]

It happened to me a couple times. I cleaned the carb each time, but didn't clean the small chamber above the needle valve. It was full of crud and I haven't had a problem since cleaning it.

I let the bilge pump get rid of a gallon or so of gas, which left a slick that quickly evaporated. A couple months later I noticed that the bilge pump wasn't working. I took it apart and the impeller was melted from the gasoline.

A valve would work fine between the Racor and pump. To meet ABYC/CG standards you now require a valve at the engine end of the line, and the main shut-off cannot be more than a 12" reach into the compartment. Make sure you don't use the cheap open body type of fuel petcock (with the exposed spring) as they can leak when worn out. I have valves screwed into both sides of my Racor, which makes it much easier to change the filter.

Dana, SV Kiskadee

[toddster]

Dana, could you elaborate on the "12 inch reach" requirement? Perhaps a link or quotation of the rule?

I've been thinking of adding a second valve and relocating my fuel filter, which is currently in the battery compartment. This seems like a bad idea: potential fuel spill + potential sparks in an area not directly connected to the blower = potential BOOM. There is room for it on the back bulkhead of the engine compartment, but that would mean a long reach over the top of the engine to reach it. (Or a crawl into the q-berth) Although the compartment is totally open, front and top, with the cover off.

At the cost of lengthening the fuel line, it might be possible to mount a valve on the front bulkhead just outside the engine compartment, for extremely easy access, but I would rather not have any fittings in the line outside of the engine compartment.

I have seen various gadgets in catalogs that connect a fume sensor to automatically turn on the blower and a bilge fuel sensor to automatically disconnect the bilge pump. These seemed to be well beyond my sort of budget. Curious if anyone has here played with such a thing though.

[ndutton]

I have seen various gadgets in catalogs that connect a fume sensor to automatically turn on the blower and a bilge fuel sensor to automatically disconnect the bilge pump. Curious if anyone has here played with such a thing though.

I have the fume sensor that automatically turns on the blower. In fact, it's armed right now, doing it's job when I'm not there, same as a bilge pump. I hope it's never needed kinda like insurance. It adds to my peace of mind.

[vabiker23518]

Thanks for Inputs

Great feedback, thanks! I've ordered carb parts from MM and will clean/install in the carb when I get back in town. ndutton: Love your valve/plate...very professional. kiskadee: will be sure to check my bilge pump for damage...wouldn't have thought of that. The entire bilge is cleaner than it's been since I've had the boat and probably in the last 20 years, so something positive has come out of this.

[edwardc]

...Anyway i have removed the carburetor and am looking at the needle that contacts the float tanks. Although it appears to be clean I am going to put in a new one just to be safe. Don't know what else could cause this. I hope that's all it is. It's amazing to me this could happen. Very dangerous

I recently had a similar experience, and it turned out that one of the float bodies was partially filled with gas! Shake it by your ear and listen. Also, try balancing in on a knife edge. If one of the floats is flooded, it will balance off-center.

With a float body flooded, the remaining float has insufficient buoyancy to keep the float valve seated tight enough, and it will leak.

[vabiker23518]

Finally Fixed

Finally got around to getting to MERLION's carb this weekend with my carb parts from MM. Replaced the needle valve/seat, float and gasket. Some minor fine debris in the chamber but I've seen worse previously. Also, I installed a fuel petcock like ndutton has in front of the carb. After putting back together (I swear the hardest part is getting the carb reinstalled and tight in my Columbia workspace!) she started right up and ran great! I used the petcock to stop the gas flow and engine started to labor after 45 sec so I shut her down. Hopefully, this is one problem I won't experience again!
Thanks for comments/suggestions!!