hi all - been a while. the weather here has been awful so last weekend was the first time I have been back on it since lasts posts. ok so as we had some fuel contamination last time so I thought I would drain the tank and clear all the lines. so I stripped the carbs down and blew out any debris and rebuilt. I then tried to undo the drain plug in the tank and as I was trying a little hole appeared from the tank and rusty water started to drain out. not good !!!!! so I think I have found the reason to a lot of my problems with bad running and starting . so I have ordered a new tank which comes this weekend so for now I have cleaned all lines out and run fuel from a can of high octane fuel. so I primed it. made sure all plug leads fired. made sure all plugs fired. and started it. it started straight up and after warming up it idled at around 900 rpm.
problems I have. front plugs either side are wet but plugs to rear are black with soot and front headers aren't as hot as ones towards the rear. seems to be running on all 8 though when rev'ed . however as I was running out of a fuel can I knew exactly how much fuel I was using. working on it all day Sunday and starting and running I used 4 litres of fuel . it was running on idle for a while and I revved a few times ( but only up to 2000rpm ) so my thoughts are I either have a leak or my idle circuit is way to rich. it doesn't change note by opening the air mix screws on the sides of the primary metering blocks. I am going to take the carbs off and block up and turn my eclectic fuel pump on to see if there is any internal leak anywhere. will also check again the transition slots underneath along with the throttle blades to make sure they only expose the amounts that should be.
checked the current power valves and they are not split. as I am on the idle circuit how can I lean off the idle circuit and get a less black/sotty plug and to get a more even burn on all 8 plugs. I understand on idle the blower may provide more fuel air mix to some plugs. and have heard that once higher rpm the mix will be more equal to all 8 plugs. currently primary jets are 70s and 1x set of sec are 78 with a another sec plate ( which I need to mod to take jets )
so staring from basics what /where should I begin ? when I went to the dyno the timing is set bang on at tdc with the stobe light. 17d at start-up going to about 22d at around 1200 rpm then heading quickly up to 30 -32d all out and then mainly flat timing .