Zenith 281F Mixture Screw

[matt B]

Hi again all.

Rebuilding the carb has got the car running but it smells very rich.

When cold if i crank the engine the engine fires immediately but if i even touch the throttle it will die. Pulling the choke out causes the engine not to start at all.
It appears to me that the engine is running to rich as additional choke (richening the mixture) causes it to not start and when cold any throttle causes it to stall.

I have replaced all the breather hoses and checked the restrictor so that is all ok (i reused the inlet gasket though). Can anybody suggest where the mixture screw is? I believe its 1 1/2 turns from bottomed out is about right. I will also smear a dab of hylomar on the intake gasket.

Any thoughts??

Best

Matt

 

[angel]

It sounds too rich, Zenith 28 IF will ALWAYS need full choke to start from cold.
The mixture screw is on the base of the carb, on the left side (viewed from driver's seat with the carb mounted on the vehicle).
I would also check float level and the jets for tightness. Sealant on the carburettor gasket is not always good, better make a new gasket.

 

[malcolm]

I'm still mentally blowing out the main jet (the one on the float chamber) with an air line, or at least unscrewing it and getting rid of the white scum. You didn't say if you had done that.

There could be 2 problems here. If it starts unusually well without choke then turn the mixture screw all the way in then out by 1.5 turns. That's a good generic setting.

Could be a timing problem in there too. Timing strobe lights are maybe £30 in the UK but can save a lot of time. Pull the vacuum advance off and set the timing at idle to between the 2 notches on the gearbox casing - that's another good start point.

It's got to be one or all of those things.

 

[matt B]

Hi again

I did blow out the jet with compressed air as recommended, my father in law is going to bring his timing gun (local factors here have stopped selling them!)

I will try the mixture

Thanks for all your help