Petrol fumes inside cabin

[parisian62]

Hi everyone

I'm getting a lot of petrol fume smell inside the cabin of Old Timer (EK wagon).

The fire wall is well sealed with all new rubbers.

I can't see any petrol leaks in the engine bay or under vehicle. I've tightened up all (triple) carbs and manifold bolts.

My only other thought is exhaust being sucked back into the cabin via the tailgate which is not very well sealed in a couple of spots...Is that a possibility?

Is it possible there is too much fuel sitting in the carb bowls?

Hoping to have a petrol fume free zone on my way to Renmark...

Stewart

[Craig Allardyce]

Unless its flooding, and there aren't any leaks, I'd be checking the fuel tank.
My ute tank was leaking at the sender under the rear floor (no tarp on) and I could smell it in the car.

[60Special]

What Craig said.
Sender unit gasket or fuel wicking up the screw threads.

[parisian62]

Hadn't thought of that...thanks guys...hopefully that's it.

[Devilrod]

My sedan did the same thing, check the sender.

[parisian62]

Doesn't seem to be the sender. All very dry and no evidence of leaks.

I've rechecked and retightened all the carb screws and will take it for a spin on Saturday to see if it has improved.

[Craig Allardyce]

Stewart is it running ok?
Please check your oil level......unlikely but possible if the diaphragm has split in the fuel pump you could be getting fuel in the oil. There is a small tell-tale hole on the side of the fuel pump that would have an amount fuel leaking out of it when running.

[Harv]

Some thoughts (some more pragmatic than others):

a) the fuel filler cap is vented, though only by a very small hole. I run a NASCO locking fuel cap (the one with the swing-type cover over the keyhole). It goes on two ways (0º and 180º). For some reason, one side of the bayonet is tighter than the other (ie 0º is tight, but if the cap is rotated 180º it is a lot looser). There should also be a cork seal under the cap that can compress/weather over time.
b) it should be possible to pressure test the fuel tank, though you would want to use only very low air pressure to prevent the tank being blown out. Take an old fuel cap, drill the centre out and fit an air hose connection. Seal the old cap vent with some solder or epoxy. Fit a valve to the air hose connection to allow the air pressure to be "locked in". If the pressure drops, use soapy water to find the leak point (on top of the tank) or look for fuel drips (from the tank inlet all the way to the carbs). I've probably got most of the fittings that you would need, though don't have a spare cap to drill out.
c) you can buy an el-cheapo flammable gas detector through eBay for about $30. This may be one way to hunt down the leak (follow the smell back to where the readings are strongest).
d) pop the top off the Strombergs and see where the fuel levels are. Should be 5/8”-11/16" below the top of the bowl rim. There is very little leeway between 5/8" and the carb flooding.

Cheers,
Harv

[parisian62]

Had a close look at the bottom tailgate and put a light inside the rear cargo area...top corners of bottom tailgate not very well sealed so have added some rubber. Grey Pride cruise tomorrow to Berrima so hopefully that's all it is...

Are fuel caps supposed to have any rubber on the inside to get a better seal?

[In the Shed]

Hi Stewart
Yes I recall they have a cork gasket or other fibre type material ring. The cap would probably still be vented though.

Regards
Stephen