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SU Float Chamber issues
Posted: Tue May 15, 2012 6:10 pm
by Wesr90
Hello Everyone, I am new to this site and have a '71 Morris Minor 1000 in North Wales.
I bought the car with it not running and so had a few things to sort out such as getting the ignition working properly. After getting it sorted and realizing the choke on the carb was not working properly the car fired up! Hurray and I had it running twice! The third time I went to start the car there was fuel being forced out of the float chamber lid (through the breather hole) and I was advised to change the needle and seat as they were worn / sticking, although the needle was opening and closing. After then replacing the needle and seat the fuel had stopped over flowing, but the car would not start!
I have been on Burlens site and checked to see that the new needle and seat I had was the same as the old one.
I was wondering if anyone here had any ideas as to why it won't fire up. Any information will be greatly appreciated, thanks
Re: SU Float Chamber issues
Posted: Tue May 15, 2012 6:58 pm
by bmcecosse
Welcome to the forum - probably just flooded with the earlier excess fuel. Take the plugs out and crank the engine over - and dry off the plugs - but DO NOT wire brush them!
Re: SU Float Chamber issues
Posted: Tue May 15, 2012 8:09 pm
by simmitc
And if it still floods, make sure that the float is not leaking.
Re: SU Float Chamber issues
Posted: Tue May 15, 2012 8:21 pm
by mike.perry
Is the fuel pump still ticking?
If you push the piston up with your finger does it drop with a clunk?
Is there oil in the dash pot?
Have you checked the ignition side? Are you getting a spark on all four plugs?
Re: SU Float Chamber issues
Posted: Thu May 17, 2012 9:31 am
by oddbod
It could also be as simple as debris under the float or hinge.
Re: SU Float Chamber issues
Posted: Thu May 17, 2012 1:14 pm
by tomas.geoghegan
bmcecosse wrote:Welcome to the forum - probably just flooded with the earlier excess fuel. Take the plugs out and crank the engine over - and dry off the plugs - but DO NOT wire brush them!
HI Intrested to know why not to wire brush spark plugs.
Thanks tomas
Re: SU Float Chamber issues
Posted: Thu May 17, 2012 4:41 pm
by chesney
Petrol!
Re: SU Float Chamber issues
Posted: Thu May 17, 2012 11:10 pm
by bmcecosse
Scraping the insulator destroys the surface...... It is permissible with a soft brass brush - as used for 'suede' shoes..... Every garage used to have a sandblast unit for plugs - but not now!
Re: SU Float Chamber issues
Posted: Fri May 18, 2012 10:12 am
by tomas.geoghegan
Hi Bmc i wont do that again.
Thanks Tomas
Re: SU Float Chamber issues
Posted: Fri May 18, 2012 7:57 pm
by MarkyB
a sandblast unit for plugs
How would this not "destroy the surface" ?
You aren't using gold plated plugs surely

Re: SU Float Chamber issues
Posted: Fri May 18, 2012 8:26 pm
by bmcecosse
It scratches the ceramic....ruins the plug.
Re: SU Float Chamber issues
Posted: Sat May 19, 2012 8:10 am
by MarkyB
It's not that easy to scratch ceramic.
Re: SU Float Chamber issues
Posted: Sat May 19, 2012 3:30 pm
by bmcecosse
It happens....I've seen plugs that wouldn't start the car after a wire brush scrubbing.....

Re: SU Float Chamber issues
Posted: Sat May 19, 2012 7:32 pm
by MarkyB
Wire brushing pre-mix 2 stroke plugs was a common procedure and didn't cause problems.
The blasting medium in plug cleaning machines would stand a much better chance of damaging ceramic but didn't cause problems either.
Re: SU Float Chamber issues
Posted: Sat May 19, 2012 8:23 pm
by bmcecosse
The glass beads would just give a nice matt finish - I guess the risk is that a scratch leaves a path for the HT to follow. Maybe it's just cheap/nasty plugs that can be harmed, but I don't brush any now. And frankly don't see the need anyway!