It sure sounds like a loose connection somewhere, probably in the motor. Quality brand name motors, which never gave any trouble, are now made in places where quality control is marginal to save money and the quality has really gone downhill.

I guess i'm not done. If that furnace is new it should still be under warranty and you have to contact your authorized dealer for their warranty service personel. They should come out for install setup. If not have them fax over the setup specs. for that furnace but make damn sure you will be allowed to touch it and not void the warranty. Have them give you an authorization number. I have info here but it is for genaric setup of any furnace. Each furnace has it's own mind and ideals. The first thing i'd check is do you have the right nozzel ? You have written, 60 deg. at .70 gals. per hour with a solid cone. That is the " B " after 70. are you sure that isn't supposed to be an " A " hollow cone ? Solid cone is pretty rare and sprays a lot of fuel. I've never seen one in a residential application. A simple thing as your chimney too big and too high will suck the fire right out of the box if the damper is not set right and give you smoke untill the pipe warms enough to draft. Even if your chimney is not at code hight the roof peak could act as a up draft ramp and suck the fire up the flue. Usually it will cause a down draft. Minimum hight is 3 feet, 10 feet back from any part of the roof peak or minimum 2 feet on a flat roof. Your pump pressure is a little high. At 120 your fuel could " fog " instead of atomize. " fogged fuel " burns incredibly fast and hot. There is no actual liquid in the spray to slow down the firing rate. This is just something to look at. Your Furnace probably will never be fixed over the net. Someone has to see it. If your paying i'll make the service call :) lol. I'll keep you in mind. I do a lot of electronics for a hobby. This month's hobby, satellite T.V. Good luck.

replace the nozzle with a .85 or .75gph x 70A Make ABSOLUTELY sure the retention head isn't burned off (look down the blast tube) you'll need a "F-3" head if it is, if it's carboned up clean it. Replace the electrodes with a standard kit ( cut to length) and use the provided tool to gap them PERFECTLY. Oil furnaces/boilers are simple, reliable pieces of equipment that is inexpensive to service yourself; they do require some knowledge or aptitude however. If you plan on servicing this unit yourself, you'll need to know how to tune it properly, and clean the furnace/boiler throughly. Do lots of reading and learning if you plan on doing this yourself. If you don't have the necessary experience, you probably should call a tech to adjust your air, fuel pressure etc. w/ a bach kit. You should also have a filter in your oil line JUST before the burner (even if you have one at the tank, if not, install one just before the burner); these filters also need to be changed yearly.

DO NOT put in a 20 amp breaker UNLESS the wiring to the furnace is 12 gauge; it is usually 14 gauge and a 15 amp breaker is correct. If you put in a larger breaker you may have unprotected wiring and you could get a fire and your insurance company may not pay the claim because you not only worked on the electrical circuit but you put it in violation of code. As far as the current readings-- the high current is the starting current and the 15 amp breaker is designed to handle that high current for several minutes;your burner takes at most only 7 or 8 amps running and your blower takes 4 amps, so if the breaker pops then you have a short or you are sharing that circuit with another one.And, by the way. reading your post, it is inconceivable that the breaker is tripping since at night you say the furnace cuts out and in the morning it goes on. Breakers don't cut out and cut in; once tripped, they remain tripped and in the tripped state they sometimes look like they are almost making, but they are not. From your description, of the furnace stopping, it may be that it is cutting out on high limit due to an overheating blower which would stop the blower and cause high temperature at the heat exchanger. But to prove the breaker theory, and as previously suggested, get a clamp-on ammeter and record the current at the breaker while the furnace is running to see if the current exceeds 15 amps in the steady state ( not startup). If so, check the current at the blower and at the burner to see where the short or partial short may be. I really think you are a little over your head on this, since you seem to be changing too many parts unnecessarily in a"shotgun" approach to solve a problem. I would urge you to get a pro in there to check this out, since some of the advice you are getting here is not accurate, especially in electricity.