I rebuilt the carburator on this oliver and it ran fine. However when I shut the tractor off gas continued to flow through the carburator like the needle and seat were'nt shut. So I tore it apart and adjusted the float. Now it does'nt leak gas, but it pops when idiling through the carburator and won't pick up the rpms. I've checked the firing order twice and tried to adust the carburator settings to no avial. I have'nt been able to check the timing, as I can't find any timing marks. The Oldboy that was working on this tractor passed away, and I'm trying to get it running for his brothernlaw. But I'm not an OliverMan. This is my first, and it's driving me crazy. Please Help