Mercury 4-stroke Gas leak

[JimS123]

9 year old 3.5 HP kicker. I had trouble last year and had the carb rebuilt. It ran fine after that.

So, it's 92 F today and full sun. I try to fire her up and she started to run but then choked and gas was running out of the carb overflow line. Shut off the gas shutoff valve and it stopped. Opened it up and it started leaking again.

When I got home and put the boat in the garage, and after cooling down I opened the valve again and no sign of any leaking.

I realize it could be a float issue, but my thought is that maybe the gas cap vent is plugged and the heat pressurized the tank. I'll try tomorrow in the driveway with the cap off.

Any other suggestions?

 

[Chris1956]

Sometimes the floats just stick, after a layup. They likely get better after use.

If it persists, you may need to revisit the carb.

 

[JimS123]

So I fired her up in the driveway and she started right away. I did it with the cap off completely. Then I disassembled the cap and did a thorough cleaning, even though it looked just fine.

Finally I put the cap back on and open the vent and she ran good then too.

So I still don't know the root cause but at least she DID run.

The motor is an auxiliary and I only start her up a couple of times each year, and run for 15-20 minutes. It's a 2016 model and my log book shows about 7 hours of total run time. I always shut off the gas valve and run out the carb as much as possible. It's stabilized fresh gas each year.

Given the type of service, is there anything else I should do?