Just made another check - I started the engine (it's been sitting now for about 30 monutes) - it runs and idles nice and smooth, I did not apply throttle. I pulled the return hose from the temp fuel bottle and watched the flow (electric pump is shut off) - it flows evenly at a low rate. After about 2 minutes the engine starts to run rougher and rougher untill it finally dies. The entire time I continue to have an even flow from the return line. Does this show that my lift pump is working ok, or does the low flow rate mean it needs a rebuild. I don't have another working 603 to gauge this against.