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 Posted: 08-29-2014 03:53 am
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davidpayne
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I noticed a large puddle of fuel under my car. There was nothing leaking from the carb area, so I crawled under. Fuel was dripping from the oil pan. I drained at least a gallon or two of oil mixed with gas.

Background: a couple of days prior, the small hose at the top of the fuel tank broke nearly in half. I hadn't noticed that when I filled up. I had a spare hose from my parts car, so I replaced it. Could the hose fracture and then filling the tank have something to do with this?

Any clues would be appreciated.

Last edited on 08-29-2014 03:53 am by davidpayne

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 Posted: 08-29-2014 05:32 am
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gmgiltd
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Hi David,
The 'small' hose on the UK spec GT anyway, is to prevent siphoning and should have a restrictor in it - it allows a small amount of fuel to be pumped directly back to the tank and ensures that the fuel line is not pressurised against the carb float valves with the ignition off.
Other possibilities are tank cap not venting allowing pressure to build up on a hot day, faulty float valves, car parked nose down hill (syphoning) or a combination of these. Hope this helps.
Gordon

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 Posted: 08-29-2014 02:23 pm
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Jim Ketcham
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In the US there is a small check valve hidden in the hose to prevent siphoning when the level in the tank is higher than the carbs. If you still have the old hose you can remove it and place it in the new hose. The parts manual shows this valve.

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 Posted: 08-29-2014 10:17 pm
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davidpayne
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Update: A piece of rubber was discovered in the rear carb that was preventing the needle from seating. Cleared it and will do a rebuild, including changing the floats on both carbs.

Regarding the check valve, we did a little exploring and discovered the vent line that exits the bottom of the trunk area and the line that goes to the canister are both clogged, and likely have been for a long time. Rather than replace all of those lines, will I be okay just running a new hose from the top of the tank that simply daylights out the bottom of the trunk?

My assumption is that the previous hose, which I had not noticed was cracked open, was allowing the pressure in the tank to escape. When I replaced the cracked hose, this sealed the leak, but due to the clogged vent lines, pressure was able to build in the tank and this forced fuel to the carb which had it's needle held open by the small chunk of rubber.

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