Smelly gasoline fumes in the cockpit indicate a healthy carb mixture? My tech says Strombergs on '69s E-Types were not adjustable to lean out. Do I have to live with a headache and bloodshot eyes after every ride?

 

I'm afraid that I only know SUs, so this may be totally off the mark for Strombergs, but have you checked the fuel float system (float level setting, crap keeping the valve open, etc.)? Anything that forces an excess of fuel through the carb due to pressurization by the fuel pump? Just a WAG...

 

could also be gas tank o-ring seal.....mine was a little weepy and had fumes in the cabin. Or as Mike says check the float

 

My 68 has twin Strombergs, no severe gas smell inside. Just the typical burning oil smell dripping from the rear seal onto the exhaust. Your gas smell might be coming from behind you and not the carbs.

 

Hello ebrand,
Your tech is wrong. Some Strombergs had a fixed metering needle in the air damper piston, but the metering jet could be adjusted up/down from the bottom of the float bowl. Others have an adjustable metering needle, with a fixed jet and mixture adjustment is made by altering the height of the needle. Each method worked, as it is just a relative position between the metering needle and jet. Look at the color of the Spark Plugs to gauge if the mixture is rich.

A rich mixture tends not to result in gasoline fumes in the cockpit. Its more likely to be a stuck open needle and seat in the fuel bowl, or other leak in the plumbing.

Regards,

Brent

 

Thanks all,
Tech already switched out the air damper/fixed needle system to a TR6 which he said were adjustable, so that's water over the dam. Now can he lean them out further? We'll see.

Also, main seal def. is dripping on exhaust, so that's contributing. I'm installing a stainless exhaust, then I'm detailing the engine and undercarriage....then also will check the gas tank 'o' ring to make is sealed.
Appreciate everybody's input, really helpful, now I'll bring this to my tech and see if he's defensive!

 

Hello ebrand,
So it should be clear to you and your tech that the Strombergs on your car are adjustable for Mixture. If your tech has merely swapped out the air damper piston for that from a TR6, including the metering needle from the TR6, then that may give you an incorrect mixture; the metering needles are a different shape/size. However, apart from the smell of fuel (not a test for too rich a mixture) you have given no indication that confirms that the mixture is too rich.

You need to determine if the mixture is too rich or not. The color of the spark plugs is a good indicator. Another method is as follows:

Remove the air cleaners to gain access to the air piston through the throat of the carburetor. With a thin plain screwdriver, lift the piston 1/32 in. (1 mm), listening to the engine note while you do so.

1. If the mixture is correct the engine speed should rise slightly for a moment, then return again to normal.

2. If it rises and stays fast the mixture is too rich.

3. If the engine dies when the air piston is lifted, it is too weak.

Regards,

Brent