Carb Leak advice
Discussion
Recently replaced the knackered Weber twin choke on my 1600M with a Weber single 40 DCOE, the carb was working great but after a couple of weeks had fuel running out of air filter, purchased a refurb kit and handed to my garage who stripped and refurbed and replaced, I now find that I get a small amount of fuel on the underside of the filter ( K&N ) and also it has obviously been hitting the chasis below the air filter as it is much cleaner than the rest, I have spoken to my mechanic who says I shouldn't worry about it and that all weber 40's spit back a bit.
So should I be concerned or not ?????
Cheers
Harry
So should I be concerned or not ?????
Cheers
Harry
Harry,
My twin 40s spit a little but it's only been happening recently so I think it's probably just that they need a mixture tweak - it's been 12k or so since they were done on a 5hr rolling road setup on Christmas eve 2 yrs ago...... they were a LONG way off, there was a ballast resistor that shouldn't have been there and when they were properly jetted and sorted it made a LOT of difference
Have you had yours set up properly, jets and all, by an expert? It might be as simple as that......then again
Kris..
My twin 40s spit a little but it's only been happening recently so I think it's probably just that they need a mixture tweak - it's been 12k or so since they were done on a 5hr rolling road setup on Christmas eve 2 yrs ago...... they were a LONG way off, there was a ballast resistor that shouldn't have been there and when they were properly jetted and sorted it made a LOT of difference
Have you had yours set up properly, jets and all, by an expert? It might be as simple as that......then again
Kris..
Hi Kris,
The carbs were refurbed and jetted by a very well respected performance garage in Newcastle, they did put the car on the rollers and gave me the printout. The car is running great and I am not too concerned about the spitting back as it is few and far between, my main concern was the evidence of fuel on the chasis. What do you think, should I be concerned or not ??
To put you in the picture, after a run out if I lift the bonnet I can't actually find any fuel on the chasis, probably evaporated, but it has obviously been there as there is a patch that is far cleaner than the rest right under the air filter, also if I run my hand under the bottom of the filter I do get fuel on my hand.
Cheers
Harry
The carbs were refurbed and jetted by a very well respected performance garage in Newcastle, they did put the car on the rollers and gave me the printout. The car is running great and I am not too concerned about the spitting back as it is few and far between, my main concern was the evidence of fuel on the chasis. What do you think, should I be concerned or not ??
To put you in the picture, after a run out if I lift the bonnet I can't actually find any fuel on the chasis, probably evaporated, but it has obviously been there as there is a patch that is far cleaner than the rest right under the air filter, also if I run my hand under the bottom of the filter I do get fuel on my hand.
Cheers
Harry
Harry. it sounds like your float chamber could be overfilling? I am not fully conversant with which model carb you have (downdraft or sidedraft) but possibly you are filling the chamber faster than you are emptying it. This is usually adjustable, but would be my first port of call. Other potential is a partially sticking needle valve sticking open due to a worn seat. This can happen after re-builds since the seat may not have been changed to match the needle.
They sometimes spit back as a result of mixture / ignition timing, but you should not be dribbling fuel.
Neil.
PS. Invest in a fire extinguisher and a master cut out switch for the battery, always cheap insurance on plastic cars.
They sometimes spit back as a result of mixture / ignition timing, but you should not be dribbling fuel.
Neil.
PS. Invest in a fire extinguisher and a master cut out switch for the battery, always cheap insurance on plastic cars.
Thinking further about it I don't know if the needle valve set up is supplied with a re-build kit, so it could be original and not been replaced.
PS. Car looks good on the drive. My Silver one is now completely stripped prior to becoming a griff 400 replica.
Will call over next time I am up there.
Neil.
PS. Car looks good on the drive. My Silver one is now completely stripped prior to becoming a griff 400 replica.
Will call over next time I am up there.
Neil.
Hi Harry,
Ok, second obvious question - have you checked to see where the fuel is actually coming from - I take it that it is on the base of the filter near the union with the carb body but is there actually any on the body itself? I'd pop the bonnet, run the car and see if there were any obvious leaks. When I first put my 40s on I had major fuel leakage problems. Nipping ups all the bolts helped a little but the car still stank of fuel and there was visible pooling in some of the webs on the carb body castings after a run. I didn't track the problem down and ended up with a nasty engine bay fire, barbequed K&Ns, melted electrics and a large bill for the repair. The carbs were stripped, cleaned and reassembled with fresh gaskets and I have had no problems since. So, in my case, it appears that dodgy gaskets in the rebuild kit were the cause. If nothing else is obvious it might be worth a try.........
Best of luck,
Kris..
Ok, second obvious question - have you checked to see where the fuel is actually coming from - I take it that it is on the base of the filter near the union with the carb body but is there actually any on the body itself? I'd pop the bonnet, run the car and see if there were any obvious leaks. When I first put my 40s on I had major fuel leakage problems. Nipping ups all the bolts helped a little but the car still stank of fuel and there was visible pooling in some of the webs on the carb body castings after a run. I didn't track the problem down and ended up with a nasty engine bay fire, barbequed K&Ns, melted electrics and a large bill for the repair. The carbs were stripped, cleaned and reassembled with fresh gaskets and I have had no problems since. So, in my case, it appears that dodgy gaskets in the rebuild kit were the cause. If nothing else is obvious it might be worth a try.........
Best of luck,
Kris..
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