1998 1800 Regal 3.0l - won't stay running
I just finished a great year of boating in the Muskoka's. I was planning to pull my boat out of the water and complete my winterization routine, when my boat, which ran fine all summer would not stay running. The boat starts fine and runs for about 30 seconds before it stalls. Upon a immediate restart, it only runs for about 10 seconds before it stalls again. If I let it cool for an hour it will run again for 30 seconds before stalling. I replaced the gas filter that was attached to the bottom of the fuel pump (first time replacing in 3 years) and blew out the filter screen that resides in the gas intake on the carb (2bbl on a Mercruiser 3.0l engine); the fuel filter attached to the fuel pump was breaking down, while the filter screen in the gas inlet on the carb was relatively clean. If I hold the butterfly valve closed, the engine will continue to run and therefore believe the engine is likely being starved of fuel and the gas is likely OK (gas is approximately 2 months old). Although I understand these mechanical fuel pumps are relatively bulletproof, I pulled the gas line from the carb and turned over the engine and confirmed gas was being pumped through the lines.
My research suggests my next move would be to check/replace the siphon valve and clean the pickup screen that resides in the gas tank, however would appreciate any insights from those having similar problems. The other thought is the needle vale inside the carb may be plugged?