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Weber - low revs fuel starvation prob?

Posted: Thu Sep 07, 2006 11:49 pm
by subanator
My Weber on an EA81 seems to starve under light load and had been a bastard to cold start. Tends to need pumping to keep it from cutting out.
This is more of a prob as the revs drop off back to idle, like at a corner, or lights to change, just dies and doesnt idle properly. Under open throttle with secondary open, it goes fine.

I checked over for vacuum leaks, seeing its the main culprit for these symptoms, but none found so far. Took the top of the carb off, dirty black silt in bottom of bowl, - is the fuel height correct when the fuel is level to the step in the bowl?

It seems to get enough fuel supply, checked and swapped fuel pump and fuel filter, as this ticker is the under bonnet type, but only fills fuel filter 1/2 way - is this normal or do I have a suction leak in the fuel supply line?

Tomorrow I will have the carby and manifold off, to clean out and re-seal gaskets. I had a prob before with the idle jets getting blocked with paint comming off the inside of the fuel tank.

Any other suggestions?

Update

Posted: Fri Sep 08, 2006 8:42 pm
by subanator
Today renewed/resealed all the gaskets on the inlet manifold and carby base.
Took the top off the Weber and blew through the jets & circuits with a cleaner. Problem still there - exactly the same.
Next to look at electrical connections and dissy. Need to eliminate this, but doubt its the prob, as it is intermitant and is at its worst under no load/idle.

Posted: Sun Sep 10, 2006 9:49 pm
by subanator
Seems to be running better now, now replaced carby base gasket and adapter gasket. A bit of mixture screw adjustment has it running better.
Might still check the float level, should have done this when it was off, but it was set up ok when I rekitted it.

Also I found that the top of the fuel bowl has a breather that suppose to go the charcoal canister, but as my EA81 doesnt have one, it is blocked off. Would this effect the fuel level?

Posted: Sat Dec 01, 2007 10:12 pm
by rtcb65
Did you ever solve the weber problem. If you have , i would like to know how. I have the same problem . I also have done what you have posted .Still have the problem though.

Posted: Sun Dec 02, 2007 10:08 am
by Busdriver
One thing you havnt said is if you have checked the accel pump. Shine a torch down the carby throat and work the throttle cable at the carby ( motor off) and you should be getting a healthy squirt in there. If not, then theres your problem!Without this squirter working it will always struggle coming out of corners or at any time until engine speed starts to increase.Also, fuel filters generally only fill up while the engine is running if they are blocked.About half full or even less indicates that there little restriction in the filter. This ( the accel pump)will make it hard to start when cold as the more you pump the throttle doesnt make any difference. Usually find a small hole in a diaphragm will cause the accel. pump to malfunction.

dead spot

Posted: Sun Dec 09, 2007 7:52 pm
by rtcb65
Yes to acc pump, i have put kit through the weber. If jets are to big ( was jetted for 2.2 litre) could that cause it?

Posted: Sun Dec 09, 2007 8:29 pm
by INEEDABEER
If the jets were too big you'd be just wasting fuel.I think it may be a float problem which should explain starvation.The other thing could be a vacuum leak.If it has a vacuum secondary it wouldn't open up properly.

weber

Posted: Sun Dec 09, 2007 9:34 pm
by rtcb65
thanks, i will check out what you said

Posted: Sun Dec 09, 2007 11:33 pm
by subanator
I never solved it properly (I have since sold the car a year ago). It did improve but got like this at times in warmer weather.

I had a good accl pump (diaphram part of the Weber Kit) and I thought 32/36DGV were mech secondaries? Yeah Float height was checked ok when apart when rekitted. Vacuum leak would account for poor running for sure.