Very frustrated.

I rebuilt my own O-200. I have significant engine building experience from a prior professional life as a Chrysler tech. I also built my own AeroVee VW conversion for my prior plane, a Sonex. I know, I know, it's not the same. One mag was less than 75 hrs when the core became available. I sent the other mag to our local mag shop for 500 hr servicing. The MA-3SPA carb also had less than 75 hrs on it, so I did not send it out for overhaul. I could put 100LL into the fuel bowl, pump the accelerator, and have fuel come out of the accelerator port (on the bench).

I've been trying to start it. I can crank and crank, and nothing happens anywhere by anything indicating an attempt to start.

I thought I had spark issues. I re-checked; I'm not 180 deg out, and all timing marks line up. I disconnected the P leads, since I didn't know if the GRT tach sense connection was somehow grounding the mags. I've had folks tell me to hold the spark lead next to engine ground and have the impulse coupler pop to produce a spark. Could not see a thing. Had other folks tell me that was a waste cuz you usually cannot see the spark anyway.... I traced all plug leads to make sure they ran to the correct plugs in the correct firing order. Rechecked using the mag synch tool. Spot on together.

I then shot some starting ether in the air filter. That produced some pops and sighs. Didn't spray much, so I wasn't expecting it to start. However, I'm *assuming* that because things were popping that *something* was lighting the fuel/air mixture, ergo, the mags must be firing.

So now I'm thinking fuel issues. Zenith tech support suggesting using a fuel pump to ensure the bowl was filling. Since my wings aren't on, and the tanks are in the wings, I plumbed up a facet pump in rubber fuel line and used a milk jug for a fuel tank. Fuel was getting to the fuel bowl because I had a slight fuel leak at the fuel linlet. Tightened that and tried again, still no sign of life. I checked all the intake manifold rubber joints.

I can understand if it started and ran poorly or only on 2 cylinders, but not having ANY sign of ANYTHING going on, I just don't know what to do.

How 'bout filling the fuel bowl with super whiz-bang carb cleaner, let it soak, then drain the bowl and retry with 100LL? Or would that ruin seals and gaskets in the carb?

I really don't want to replace the carb unless I know for a fact that it *IS* the carb. ~$1000 to "just check" is something I care not to waste.

Thanks for any suggestions. I'm at a loss.