Here's a fix I wanted to pass along.
I tried for days to get my A4 to start for the first time this year. First I put some Marvel oil into the cylinders, let it soak in overnight, and cranked to get the pistons lubricated again after 5 months off. I cleaned the carb, put on new filters and fuel hose, new cap and rotor, new plugs, new coil and EI module. Set the initial timing according to Don's video. Using the bail next to the mechanical fuel pump, I pressurized the fuel line to the float valve in the carb. It took a while to hand pump gas from the tank, through the filters, and up to the float valve before I no longer felt resistance on the bail, and it went limp. Fuel pressure was 3 and holding. In the past the engine would start once the fuel line pressurized, but not this time. Spark was improved after replacing coil, EI unit and optical trigger. But no sign of it wanting to start. Turning the distributor a bit back and forth made no difference. The choke worked properly. Compression is ok. No water in the oil.
So I called the local boat engine guy, and he had it running in 10 minutes, using a trick that I had not heard of anywhere in the Moyer manual or forum, probably for good reason. It seemed a little scary at the time, but it worked. After checking for spark by holding the coil wire over the block, he pulled a spark plug, and it didn't smell like gas. Then he asked if I had any starter fluid, but I didn't. So he actually poured maybe a tablespoon of gas into the air intake, through the flame arrestor. (I turned on the blower.) Then the engine finally sounded like it wanted to start. So we turned the distributor a bit, and bingo, she ran. Once running she could draw fuel in no problem. We turned the distributor to make it sound better, and again under load at cruising rpm. It has been starting well since then.
I don't know why priming the fuel line with the mechanical bail was not enough to get her to run this time. I thought having good fuel pressure would be enough. There may have been an airlock in the line despite the fuel pressure reading. Maybe the MMO I put in the cylinders was affecting ignition. But apparently, pouring a bit of gas into the air intake enabled the scavenge tube at the bottom of the carb to pull the gas into the intake manifold, bypassing the carburetor. Then the air/fuel mixture became rich enough to fire. Another Atomic 4 educational moment.
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