10 replies to this topic

[jonjosar]

I have been rebuilding my 1275 over the last 3 years or so. Fitted the engine with all its ancilliaries and it did start and run momentarily.
I know it's getting fuel as I've checked for supply to the carb. Spark is erratic. Lucas 59d distributor with new points and condenser. Checked resistance at the points wire and all seems good. Ive static times it to 8 btdc and it does fire momentarily and when I give it a rev, it does out and then will turn over and won't start again. Carb is a 38 HIF, Plugs seem very wet but if i pour petrol or carb cleaner into the inlet, it fires again briefly. I've changed the needle to an AAA on the carb as I thought the original looked bent. Set the float level as per SU instructions. When I remove the dash pot, there seems to be fuel oozing up at the needle valve and I can feel wear in the dash pot where it travels up and down on the carb body.
Anyone know if this fuelling is a symptom of anything?
to be honest, I think the carb is goosed. Its obviously hard a hard life as it shows signs of corrosion on the dash pot so it's probably been lying up for a good while.
It's my intention to fit an electronic distributor. 65dm but my gut feeling is that even though the spark isn't great, it's a fuelling issue.
Any help would be appreciated. Thanks

[cal844]

I think you need to check the fuel is getting to the carb in good amounts. Also is the fuel fresh? If it's old fuel it won't go. Try the timing at 10° with the electronic dizzy, I usually just move the dizzy in small increments enough to get it running, then finalise the timing by ear.

You'll also need an electronic type coil for the 65D dizzy, I'd suggest getting the advance checked and tweaked to suit

Edited by cal844, 08 May 2019 - 12:49 PM.

[unburntfuelinthemorning]

You say there's fuel oozing up at the needle valve when you remove the dashpot.  Do you mean it's oozing from the jet?

[jonjosar]

You say there's fuel oozing up at the needle valve when you remove the dashpot.  Do you mean it's oozing from the jet?

Yes, out of the centre where the needle would fit. To me, that would indicate that the float level is high or the needle valve is stuck but i checked that when i was setting the float level height by blowing through the inlet and moving the needle valve up and down. I've ordered the correct coil for the dizzy, an intermotor, part number GCL143. Another strange thing is that when i fitted the new points, i set the gap at the same time i was setting the static timing so the points where set on the lobe for cylinder No.1. When i turn the engine so that the rotor arm points to no. 3, the heel of the points is not on the distributor lobe.When i open the points manually, there is very little spark at the gap and when i turn the engine over with the starter, there again doesnt seem to be much of a spark there. Anyhow, i'll need to establish that i have a good basis so hopefully, the replacement distributor and coil should be a reference point. 

[cal844]

What colour wire is at the coil +? (white or pink/white?)
It could be that there's corrosion in the wiring or the connections

[unburntfuelinthemorning]

It might be flooding (oozing fuel at jet and wet plugs).

 

There's an air vent somewhere for the float chamber.  Not sure where on an HIF but check it's clear.  If it isn't the air inside will compress as fuel is pumped in and fuel can then be forced out of the jet at pump pressure.

 

Replace the float chamber needle valve if there's any sign of wear on the tip and fit a fuel filter between the pump and carb to stop any debris getting in there.

[jonjosar]

What colour wire is at the coil +? (white or pink/white?)
It could be that there's corrosion in the wiring or the connections

Its white. I,ve measured the voltage at it with the ignition on and its 11.70 volts. to be honest, i dont know what coil is fitted as it was on the car when i bought it but as i said, i,m going to fit a 65d electronic distributor and the matching coil and if i'm right, i think this coil definitely needs 12 volts. 

[cal844]

What colour wire is at the coil +? (white or pink/white?)
It could be that there's corrosion in the wiring or the connections

Its white. I,ve measured the voltage at it with the ignition on and its 11.70 volts. to be honest, i dont know what coil is fitted as it was on the car when i bought it but as i said, i,m going to fit a 65d electronic distributor and the matching coil and if i'm right, i think this coil definitely needs 12 volts.

Yes it definitely needs 12 volts, as long as you don't have any voltage drop between the battery and coil it should be ok

[jonjosar]

Thanks Cal. 

My plan is to try and fix one thing at a time rather than just throw ideas and new parts at it " willy nilly" so to speak.

This build has literally been nut and bolt. The battery is new, the fuel is new, etc etc. If the distributor doesnt fix it, then it might just the excuse i've always needed to buy a Weber. As much for the sound as for performance.

I meant to say earlier also that i have sprayed carb cleaner over all the induction gaskets, brake servo pipes etc when i'm turning it over and it doesnt make any difference so i think i've ruled out an intake air leak.

[jonjosar]

Think i may have solved the problem...but i still dont know for sure what exactly was causing it.

I fitted the lucas 65d electronic distributor and static timed it to 10 degrees BTDC. Still didnt want to start but i was now getting a really good spark

( i know that for sure as i got a great shock off the plug ). So decided to exchange the carburettor for a Metro HIF38 that was on a car that i new started and ran. Pretty much started up straight away as soon as the float chamber was filled. No idea what was wrong with the older carb but something wasnt doing what it was supposed to do.

Thanks for the advice all.

[cal844]

Glad to hear you've fixed it. The carb may have had crud in it somewhere