I've read a lot of the discussions about problems with L-drive so I know its a sore subject but here goes.
I believe I messed up my engine by forgetting to put oil in... I ran it pretty hard (pulling a tube) for about 15-20 mins, then stopped and put in the oil. It ran great for the rest of the day but the next day I heard a small pop and lost a lot of power, could only get 10-15 mph. Long story short it scored 2 cylinders and I only had about 30 psi head pressure in one of them. I purchased a rebuilt power head, installed it and can not get it to start. It seems that I am not getting fuel to the carbs, I disconnected the hoses and "no fuel". Reading the description and operation of the fuel pump in the Clymer shop manual its a bladder/vacuum/pressure operation. I replaced the bladder and the main check valve no help, I still do not really understand how it works. With the pump removed as I spin the eng there is only a small very slight puff of air coming out of the port (the small hole in the block that the pump backs up to) the way the book reads I would think the air coming out should be quite strong and I should also feel a vacuum. There is hose also coming out of the block connected to the other side of the pump, and from that I feel no suction or pressure. Is there something wrong with the new eng or am I doing something wrong? BTW I verified it has spark to all 4 cylinders.