zah_chronicler

Thanks I will check some of this out. I will remove the jumper bypassing the ballast resistor I was getting the 9v out of it and thought that might of been the problem. I haven't ran it much since doing that. Hope the coil is still good

i know for certain that the choke is working fine. Electronic automatic choke opens as it gets going and stays open once hot. The fuel level in the sight glass stays right at the etched mark What is the leak down test Siempreloco mentioned Also do i or do I not need a replacement resistor to go into the pertronix setup. Still using stock coil

. I have a 1974 L18 620 with stock hitachi carb. My troubles began over a year ago now. I had gotten this truck running from nothing to running like a dream. I was using it daily with only some minor fiddling necessary to keep it happy. One day while getting off the interstate it basically stopped wanting to accelerate at all. I was able to limp it along in idle letting the clutch out slowly. I have not since been able to get it to run smoothly. I have been worried that an internal engine part broke but can't seem to diagnose what. The best i can tell is that the engine is running incredibly rich. All the spark plugs were fouled out with thick black soot. I had already done work on the internals of the engine and rebuilt the carb when I first got it. Everything worked fine for over a year so i don't think any of that work was a direct cause of this. I have since tried to thoroughly check and clean systems of the engine. It now will idle but not smoothly accelerate. There is a white smoke in the exhaust that smells sometimes like gas. when I do accelerate I can get the engine to rev as high as I want but get a lot of black smoke. Not getting back firing. plugs are getting black and wet now, seems to be gas and maybe some oil. Now that it will idle I am also noticing a gassy smell to the oil. I have taken the carb off cleaned it thoroughly, I have checked the entire electrical ignition system,(previously put the pertronix induction system on instead of the original points) found a resistor was only allowing about 9 volts into the main ignition coil, got that taken care of and now have 12v. The cleaning and new part has helped but still getting really bad combustion. I am wondering if it may be the carb still or if I should look at other parts. A compression test showed equal pressure on all cylinders but I don't know that the actual pressure should be. I want my datsun to rise from the ashes again.

was thinking about shutting off parts of the carb that try to make it more environmentally friendly so that it is a simpler system to trouble shoot is that a good idea. If so what are some easy reversible ways to do so for example the BCDD

wasn't sure if this forum group wanted to keep each problem more seperated. Sounds like Devilsbullet baught a Weber, I am thinking of doing the same but am not entirely sure where my problem is. Carb or something worse like worn rings

My gas level seems to stay right at the etched line on the sight glass. I even pinched off the fuel line at the filter watched the level slowly fall then then let go and it returned to normal. I can start a new thread if that would be better

Glad to find this thread. Sounds similar to a problem I have been dealing with. I have a 1974 L18 620 with stock hitachi carb. My troubles began over a year ago now. I had gotten this truck running from nothing to running like a dream. I was using it daily with only some minor fiddling necessary to keep it happy. One day while getting of the interstate it basically stopped wanting to accelerate at all. I was able to limp it along in idle letting the clutch out slowly. I have not since been able to get it to run smoothly. I have been worried that an internal engine part broke but can't seem to diagnose what. The best i can tell is that the engine is running incredibly rich. All the spark plugs were fouled out with thick black soot. I had already done work on the internals of the engine and rebuilt the carb when I first got it. Everything worked fine for over a year so i don't think any of that work was a direct cause of this. I have since tried to thoroughly check and clean systems of the engine. It now will idle but not smoothly accelerate. There is a white smoke in the exhaust that smells sometimes like gas. when I do accelerate I can get the engine to rev as high as I want but get a lot of black smoke. Not getting back firing. plugs are getting black and wet now, seems to be gas and maybe some oil. Now that it will idle I am also noticing a gassy smell to the oil. I have taken the carb off cleaned it thoroughly, I have checked the entire electrical ignition system,(previously put the pertronix induction system on instead of the original points) found a resistor was only allowing about 9 volts into the main ignition coil, got that taken care of and now have 12v. The cleaning and new part has helped but still getting really bad combustion. I am wondering if it may be the carb still or if I should look at other parts. A compression test showed equal pressure on all cylinders but I don't know that the actual pressure should be. I want my datsun to rise from the ashes again.