HI, took carb apart to clean out, mind you its a brand new one, not dirty at all, then put it back on still same problem, then I put a old carb on car going ok just needs fine tuning, so much for buying a new carb from eBay thanks everyone for their help.

the exhaust is wet black

If petrol is overflowing out the top of carby then your needle & seat are not sealing,maybe a bit of crap under the needle,worn needle or even a collapsed float,if you look at your exhaust tailpipe is the soot: wet or dry black or grey dry or white?

hi Iam back took it for run no smoke up hill or down put in my garage then try to start it but it would not go, got a new dizzy cap, new points, rotor button, now back firing in carb, and petrol coming out of top carb this engine is driving me nuts any ideas

If it blows smoke under load ie:going up a hill its usually rings,if a good test is to drive up a hill under load if you have a trail of smoke its rings,coast down a hill in 3rd gear and only apply the throttle at the bottom if it smokes then,then its probably valve stem seals,as benny said its good cyl comp so I doubt if its rings,and don't forget a12's have two seals per valve,I've seen quite a few heads that haven't had the small "O"ring fitted to the top of the stem

Right, the hose isn't usually a problem.

To test if the valve is the problem, clamp the hose shut (using vice-grips) and drive it around. If the problem clears up, the valve is the problem.

hi benny, I took the hose off the PCV valve and it sucking good so it couldn't be that

nissan dealer. part number. 11810-A3500 ASSY-CONTROL VALVE CRANK CASE EMISSION A12/14/15

thanks I have cleaned the PCV valve and where would you buy another one from

thanks I have cleaned the PCV valve and where would you buy another one from