Holley Carburetor

[Egorto]

Page 14, positive displacement pumps???

[rickf]

Point being? Tell me what vehicle you have seen that pump on. I know of two, lets see just how knowledgeable you are. And while you are thinking about that tell me why any manufacturer would spend the extra money to put a pump on a vehicle that puts out much higher pressure than the carburetor requires. Then they have to spend more money to put in a regulator which also adds complexity to the system that they need to maintain. One thing the military looked for was simplicity and ease of maintenance. And especially by the time the M-151 came around money was a big factor also so the manufacturers had to not only meet specs but also had to be low bidder. You do not do that by adding parts. I don't know what your background is but I have been doing this as a master ASE AND SAE certified mechanic for 40 of the 50 years I have been wrenching. The shop I owned for many years specialized in carbs and fuel systems. I tore down an electric A1 pump on here a couple years ago, I guess I am going to have to do the same with the A2 pump. I do not have one on hand at the present time but when I get one I will be sure to do a detailed teardown and full description of all the parts.

[Mark]

I did the running test on the A2 for the spark plugs, the spark plug electrode was grey on the tip, the rest of it was black,I thought the electrode would be one color--grey being normal, black is too rich of a fuel mixture

[rickf]

That could also be an indication of plugs that are too cold. What plugs are you running? One of the biggest problems with older antique engines and especially when trying to read the plugs is that these engines are babied now, nobody runs them hard and to their full rpm and load capacities. So the plugs never get up to full temperature.

[Mark]

2245, when driving I rev the engine to max rpm in 2nd, 3rd gear in town.On the hwy, 4th gear- 60-65 mph.I don't know the heat range

[rickf]

Then it sounds like it is running rich. When was the last time you serviced the air cleaner? and the float level will have an effect on that but other than that, idle mixture and main jet settings, Considering you will not find any other main jets what altitude are you at? Above 8,000 feet will also give you a rich condition.