Timing

[Captin840]

I can't get my timing right. When you turn the truck off it will diesel so you have to put it in gear and kill it that way. And it also stutters or Miss's when your in 4 gear and high rpms.

[datzenmike]

Not the first thing I would suspect.

 

For dieseling to occur you must have heat and fuel. 

 

 

Idle set too high will make the idle cut solenoid useless. Gas and air will be supplied by the primary barrel and not just the idle circuit. So make sure the idle is around 700.

 

Some one may have had trouble with the idle cut solenoid and taken the internal parts out which will prevent it doing it's job which is to shut off fuel to the idle circuit when the ignition is turned off. Turn the ignition on off on off on off (don't start) What you should hear at the rear of the carb is a soft clicking sound (presumably it is working)

 

Choke not shutting off (fully opening when warmed up) Take the top off the air filter when warmed up and look. Is the choke plate fully vertical and open, or only part open??? Over rich condition will soot up the combustion chamber and cause hot spots that can work like a glow plug in a diesel. Choke on also means the fast idle cam may be on as well

 

Carburetor flooding will do the same as the choke being on. Maybe the fuel level is set too high.

 

Wrong plug make (always use NGK) and the proper heat range. An over heated plug will also act like a glow plug.

 

Over heated engine. Use an IR (infra red) gun and 'shoot' the thermostat housing to get an exact temperature reading. Should be in the 185-190F range.

 

[banzai510(hainz)]

Is this still point ignition? dual points?  I use the main points and disconnect the 2nd set(the one with the smaller condenser.

 

Run on after shut off is common if a Weber carb is installed w/o the idle cut out as the stock carb had on later Datsuns.

 

the high speed cut out could be gas filter. maybe timming off or a worn or points not set correctly or maybe even a worn out bushing on the dist . Check by see if the dist shaft wear the points are have side to side wiggle. This might open/close the points out of time.

 

could be condenser but I think it would cut out on all gears

 

get a timming light and set to 7 to say 12deg btdc and try it out.

 

these are simple motors and EZ to fix

Edited May 9, 2019 by banzai510(hainz)

[distributorguy]

If your timing is set higher, the throttle blades can be closed more to reduce idle speed which in turn reduces run-on.  

 

The real fix for run-on is to fix all your vacuum leaks and richen the mixture.  Its caused by hot spots, and fuel is a coolant.  

 

Your high speed stutter is caused by a lean condition, so I suspect you have vacuum leaks.  Replace every rubber hose under the hood, check the throttle shaft for movement/wear, and disconnect and bypass the brake booster to make sure that's not leaking as well.  Cap every port on the carb until it runs better, then work back in the pieces you need like the brake booster.