Intermitant Stuttering problem

[aerodat]

I have a 1970 260 with an intermittant stutter. Engine misses/cuts out/jerks usually not on full power but just on cruise at about 100-110 km/hr . It does not seem to have any consistent pattern and is not possible to reproduce on demand.

 

Where shoul d  I begin to look-fuel or spark ......any suggestions?

[260Coupe]

Sound like it is running lean on cruise........what carbs are you running?

 

You may need to check your mixtures and reneedle your carbs, if you are running 240 carbs try richening up a quarter of a turn (this will also make them rich every where but may diagnose the problem)......the best option is to dyno tune with a gas analyser.

 

cheers

 

Alan

[Lynton]

Change your petrol filter, as you may have some bad fuel with water in it??

Lynton

[Zedman240®]

What sort of ignition system are you running? Points or electronic? could be a ignition problem. I'd check cap, rotor, and all others first. Put a timing light on it and see what it says. Start with the basics.

[pauly_adams]

first i would check your timing and if thats fine ( mine usualy around 7 degrees ) then i would say you have the same problem as me and your dizzy is rusted to hell internaly which was causing my car to missfire when ever it felt like it.

 

cheers pauly

[aegean]

If it is rusted up or generally gummed up, it is an easy job to take it apart. I am in the middle of rebuilding one at the moment - not for a Z but they are basically all the same. There are quite a few web sites that show you the process of rebuilding a distributor, so you get some good pictorial shots. I would recommend using Bosch distributor grease, and no, I don't work for Bosch !