N/s carb flooding!

P

prospect8816

Member
Hi all, yes it's me again. This is becoming irksome!

The problem this time is flooding in the n/s carburetter. My car has twin SU's H1F6's fitted.

The problem began after my classic car mechanic had come to my home Friday 13th April to work on the carbs. He stripped down both but only replaced the float in the off-side one as the near-side one when tested in petrol, seemed to be ok, i e no leaks. He also replaced & fitted 2 new needle valve kits, all gaskets/seals etc, cleaned & tested, ok. He had also found what he describes as, "crud". This was found in the Float Chamber and in the Float Chamber Cover! This was mentioned before about 2 years ago to the forum!!
Tried taking the car to a show last Sunday 15th April, but only got 1/2 mile from home before the car lost all power. So turned around and came back home. Once home I noticed petrol pouring out of the pipe onto the ground. When carbs checked, the n/s one was found to be flooding! Apologies, but for the life of me I cannot remember what the pipe is called that goes from the carb and takes excess fuel from carbs to the ground!

All this work was first done in October 2009 by same mechanic and again in 2010 by a company called "Tune-Up" based in the Brighton area. Now just 2 years later, the same thing again!

What is going on??

Also, when my car was in his workshop recently, he replaced the old Facet fuel pump with a new SU Electric fuel pump with 12v polarity/AZX 1307 and removed the fuel regulator as the new pump regulates itself. Could this new pump have a bearing on this flooding within the o/s carb?

Help please

Paul
 
Electric pumps can overpower the carb needle and seats depending on the pressure they are providing so maybe it needs the regulator in the system. The pipes you mention are just called Overflow Pipes, because that's their purpose, to direct the excess fuel from a flloding carb on to the floor, rather than it all pooling on the top of the (hot) engine. You're not really going to know exactly what's happening without either taking the electric pump out of the system, or removing the carb and checking the float/needle/seat.
 
Hi Paul,

I would start by removing the n/s carb and checking that the float has not taken on petrol in the time since your mechanic had a look at it. When a float fills with petrol it sinks so the fuel level within the bowl rises until it pours from the overflow as yours is doing.

I am inclinded to think that if your replacement fuel pump was the cause, then fuel would also overflow from the o/s carb, and as it isn't I'd start with the removing and inspecting the n/s carb first.

Ron.
 
SydneyRoverP6B said:
I am inclinded to think that if your replacement fuel pump was the cause, then fuel would also overflow from the o/s carb, and as it isn't I'd start with the removing and inspecting the n/s carb first.
Click to expand...


Not necessarily, it will overcome the one with the least resistance first, causing the pressure to drop so the other one remains OK.
 
Hi i had the same, the float was leaking and full with petrol, so i buyed a new float ,but the old one i tested for repair and is still in it , blowed with compressor the float dry and glued it with loctide second glue , you can try it but when it is your daily driver i prefer a new one.
Regards Hans
 
Hi guys,

I have now had the car returned to me after 3 weeks away at my mechanic's workshop. He & I came to an understanding that if the problem was solely to do with the o/s carb, then he would stand the cost of replacing any parts plus labour. All well & good. He also stood the cost of having the car traillered from my home to his workshop. Cost £35.00.
The car has had the following remedial work done: Strip & clean n/s carb & fit new float, set level as required. Fit (Fine) fuel filter underbonnet. Drain fuel tank/filter fuel and move fuel pump feed so pump draws from higher position in tank. Remove fuel pump and clean. Fit "Pre" pump filter. And roadtest ok! He then drove the car for the best part of a week or so, covering about 100 miles without fault! Total cost £182.55 incl labour/parts & vat.

So I sincerely hope that is the end of this problem once and for all! But don't hold your breath! I'm afraid i've lost faith with this vehicle and shall probably sell it on once the summer is over. So if you know of anyone looking for a classic Rover P6B 3500 v8 and has fairly deep pockets, then send me an email. All reasonable offers considered.

Paul
 
[quotemove fuel pump feed so pump draws from higher position in tank][/quote]

Is this a good idea ? You'll be getting fuel starvation going uphill unless you keep the tank well full

Fit "Pre" pump filter
Click to expand...
- That's amking the pump work harder and possibly more prone to vapour lock

If he'd cleaned the tank when draining it, both should be unnecesary
 
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