1984 720 Napz 20 timing/weber help

[sidebeub]

So I put a weber on my little truck and its running ok, but have a few fine tuning questions. It stumbles a bit at low rpm and idle is low when its cold. Once shes warmed up idle is good, stumble is still there but not as noticeable. She does diesel a bit when hot during shut off. I'm thinking its timing related. My Haynes book shows 12-15 BTDC, but I see others commenting it should be around 5-7 BTDC. I don't have the stamp under my hood to tell me factory settings. Does anyone know what factory settings would be my truck is a 1984 2wd 2.0.

 

I'm using a timing light, disconnecting the distributor vacuum line and plugging the distributors hole when checking. (not sure if you plug the vac line or dist. hole) its around 7 now.

At 12-15 she runs good, but really struggles to idle when cold. I turn up idle, but once we're warmed up idle is too high.

 

Appreciate the help! Love these little trucks!

[datzenmike]

I have that at home but may be the same as the Z24 which is 3 +/- 2 degrees. Definitely not 12 degrees.

 

Won't hurt to disconnect the vacuum advance but this is a hold over from the 50's and into the '60 when vacuum advance was taken from the intake. Now it's from a port on the side of the carb above the throttle plate, so there should be none at idle if everything is set right.

 

I would confirm that both intake and exhaust side plugs are firing.

 

The choke probably needs to be set richer than it is.

[sidebeub]

Thanks Mike! I know the compression was higher in the z20 so wasnt 100% sure what info to base off of.

The choke crossed my mind as well ill tweak it.

Plugs are new, wires about 5 years old I'll confirm spark all round though.

I'll try 3 +/-2 degrees, have a broken distributor bolt to deal with now ? LoL

 

[datzenmike]

OK the Z20 is 5 degrees +/- 2 degrees. Don't forget the Z20 has a knock sensor and ignition retard so stick to the 5 degrees.

[sidebeub]

Timing is set at 5 now thanks again Mike!

So for adjusting the choke, do I just move the coil inside the housing or is there a fast idle screw I'm missing?

Found a write up on the forums already so I'll try to tweak my choke.

[datzenmike]

Some years the choke is factory set and rivetted so it can't be messed with. If you can adjust set it on a cold engine. Turn till the flap closes. This should get you started.