I have just spent ages trying to get a rebuilt TCS engine started. Everything was timed right, all new electrics, float level checked, but it just would not start. I had to use Easy Start to get it to fire, then after it started, it now starts first time, every time.
I think it needed a fast turn over to get the fuel flowing through the Weber carbs properly. Just pumping the Webers to squirt fuel in them had not worked. I pumped the carbs 4 times, and squirted Easy Start into all 4 inlet manifolds with the butterflies open, and to my surprise it fired up. Until then, I had flattened the battery 7 times trying to get the thing started.
I had used JB's trick of packing the oil pump with Vaseline, and that worked very well. Thank you JB.