• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR6 Carb float chambers

Share this page

C

ceedub

Senior Member
Country flag
Offline
Finally got my '72 TR6 on the road after three and a half years of a frame off resto. One thing that I am noticing is the number of cranks required to start the motor after the car has been sitting for a couple of days. Once started, any subsequent starts during the day happen right away. The opinions that I have is that the float chambers are somehow becoming depleted of fuel after sitting for a few days requiring so many cranks for the pump to refill the bowls. Is there a possibility that the fuel is somehow siphoning back? There does not appear to be any fuel leaks around the bowl or pump. Would a one way valve in the fuel line be of any use? There does seem to be a slight gassy smell in the garage but I can't figure out where it is coming from. Any opinions as to a solution to keep these bowls full over time? Thanks.

Ceedub
 
Check the plug and O-ring on the bottom of the float bowl. The O-rings dry out and they can leak.
 
And check the fittings that enter and exit the fuel pump....

Cheers
Tush
 
For the o-rings, don't feel obligated to buy a rebuild kit to get what you need. Measure the gland diameter and the cross-section of the old o-ring. I forget the exact size but these are seals you can source at a local bearing house or auto parts store. (They are inch size... and in inch o-rings, sizes are nominal... i.e. a 1/16" cross-section o-ring is really 0.070" thick... so loosely interpret the size you measure). Buy Viton if they have it. The original seal would have been Buna-N (Nitrile). Both materials are fine with gasoline but Viton holds up a little better/longer.
 
Maybe it's the choke that needs adjusting or the ignition timing is off.
BUT..there is a way to determine if there is fuel in the float chamber after the engine has been sitting idle for a few days..
If you want to try that, remove the air cleaner housing.
On the carb's air box mounting flange you'll see a round hole at about 10 o'clock, in between the 2 threaded holes...it's a vent.
Get a soda straw or tube and while lifting the air valve use the tube to blow into the vent.
If there is gas in the float chamber, it'll bubble up around the needle.
 
Thanks for the tips folks. I did put a carb kit in with the restoration so the O-ring is new. Can't see or feel any leaks around the pump. I will give the soda straw a go to see if there really is any fuel in the bowl and get back to you. Is there any chance that fuel could be siphoning out of the bowl? I understand that the pump has a one way valve built in but who knows. Maybe another one way valve somewhere in the line would help if the bowl is empty?

Ceedub
 
No, I don't see the possibility of fuel syphoning out of the float chamber. The fuel level isn't high enough to reach the float chamber needle valve in the fuel inlet port.
 
Check the valve in the fuel pump. They go bad once in a while and will not hold fuel or pressure if they set for any length of time. You can get rebuild kits, or a new one. Unscrew the out line after it sets a day or two and see if fuel is in the line.
Wayne
 
Back
Top