Turns over but fuel not getting through?

[Tim M]

OK, I have now a new fuel tank and fuel is getting to the carb but it still doesnt fire up. Very annoying, so close and yet...any ideas?

Tim

[Tim M]

I think I might need to clean out the carb, does this sound right?

Cheers,

Tim

[chesney]

I take it the fuel pump is working?
Start by taking the lid off the float bowl (3 screws) and seeing if there is any petrol in there. There's no point in making more work for yourself by rebuilding the carb.
If there's lots of petrol there, then it's after that point of the carb, ie blocked jet or line etc etc. If not, test the float valve by (assistant needed) switching the ignition on and operating the valve by hand, and seeing if some petrol flows freely into a canister.

[Tim M]

Thanks I'll do that over the course of the next few days. The fuel pump is now working fine . Thanks very much for the advice, Tim.

[bmcecosse]

Does it fire up when you pour an egg cup of petrol down the carb ???? I'm sure I have suggested this before......If not - then you have an IGNITION problem....not a fuel problem.......

[Tim M]

The float bowl was dry so I blew down the top of it and it seemed to clear the obstruction at the top near the float. I put it back on and it filled fine...the engine coughed once, my heart stopped... but then just turning over and not firing up. A flat battery stops play for tonight.

This car has been laid up since the late 1980's, do you think a clean out of the carb is next. The plugs, ponts, leads etc look clean but I could replace them if the carb is not the problem...the orignal blockage in the fuel line was rust from the tank which may now have stuck in the carn somewhere. Should I consider replacing the carb altogether or will cleaning it out be sufficient?

Thanks again chaps.

[simmitc]

You might have a blocked jet, there's not much else on the petrol side. To remove and clean, undo the small screw that holds the choke operating linkage to the jet - don't lose the screw or spacer washer. Next undo the nut that holds the flexible pipe into the bottom of the float chamber. Watch out for the rubber sealing ring and brass washer - you might have to dig them out of the housing. Note the correct order for reassembly. Clean the jet by blowing through it, and then reassemble. Working on the carb requires cleanliness.

[bmcecosse]

Please put some petrol down the carb and crank it! If it fires up - it will likely clear any crud in the carb!
Edited to remove 'over excited' remarks.

[kennatt]

Its highly unlikely that an SU carb jet can get blocked(But possible),But easy to check,and rectify,take top of the carb off,the piston plus chamber(three screws),lift out the needle assembly,carefully,and lay to one side,look down at the jet and you should be able to see petrol just inside the jet. If not then the pipe from the bowl to bottom of the jet is blocked,get a byclycle pump and put the end over the jet and give it a few strokes(Then clean out the bowl).No need to strip the jet assembly from the carb. If you can see petrol then the simple matter of pulling the needle will have removed any crud from the jet.Put everything back together,screw the big nut under the carb right in,then unscrew 12 flats of the nut,this is the basic setting, which then needs fine adjustment after the engine start. I see that you have poured petrol down the carb and it started,so should be ok after doing the above....................Not trying to be funny,but you are pulling the choke and seeing it work at the carb end

[alexmcguffie]

What kennatt says should do the job now by the sounds of it. I'm suspecting that when you take the top off the float chamber there'll be a lot of rusty silt at the bottom dragged through from the fuel tank. As it has been left standing for years this may have solidified causing your blockage/restriction. The filter in the fuel pump might be worth a look too. They aren't the best quality filters in the world!

[katy]

get a byclycle pump and put the end over the jet and give it a few strokes

Make sure you put a rag over the bowl when you do this, and a catch pan underneath. JIC.

[Tim M]

Thanks I'll give it a try as putting petrol into the carb isn't clearing things out.

[bmcecosse]

But does it fire and run for a few seconds when you add the petrol ?

[Tim M]

Hi

No, it fires, coughs then makes a sighing noise (starter motor?). I am charging up the battery again as it seems to be stressing the (new) battery. It is getting slightly better and nearly ran the last time I tried it earlier today.

[bmcecosse]

Hmmm - if Ignition etc is all ok it should RUN for a few seconds. Does it seem as if the engine is kicking back against the starter- which would indicate over advanced ignition. Perhaps retard it for now till it starts and runs!

[Tim M]

Hmmm - if Ignition etc is all ok it should RUN for a few seconds. Does it seem as if the engine is kicking back against the starter- which would indicate over advanced ignition. Perhaps retard it for now till it starts and runs!

How do I retard the ignition? I blew a couple of fuses trying to start it again, the carb seems clear but still not running so it looks like it is to do with the ignition.

[chesney]

The ignition isn't fused, if it's blowing fuses that's something else!

[bmcecosse]

Indeed! No fuses there at all.... on the dizzy should be a knurled knob and on the body R and A . Turn it towards the R mark to Retard. OR -slacken the clamp bolt and the two fixing bolts and gently turn the dizzy ant-clock a small amount - say 1/4" - and then retighten. Try again...... I can't remember now - but have you checked the carb piston rises easily with finger pressure - and drops back freely ?

[Tim M]

Indeed! No fuses there at all.... on the dizzy should be a knurled knob and on the body R and A . Turn it towards the R mark to Retard. OR -slacken the clamp bolt and the two fixing bolts and gently turn the dizzy ant-clock a small amount - say 1/4" - and then retighten. Try again...... I can't remember now - but have you checked the carb piston rises easily with finger pressure - and drops back freely ?

Great, I am away this weekend but will check the carb piston first before I turn to the ignition system next week. Thanks again!

[Tim M]

- but have you checked the carb piston rises easily with finger pressure - and drops back freely ?[/quote]

I have now, it doesn't. It squelches like boots stuck in mud and then sticks up and needs to be pushed back in.