Makita 6421 flooding issue

[timq585]

I Purchased the saw new in December, ran a few tanks of gas through it in the winter. The saw ran perfect out of the box, fired right up, idled well, would restart when hot, and also when cold. Things got busy in the spring, and I really don't cut much firewood in the summer months, so it was put away in my shed until this weekend. I had a tree go down on the property near the driveway so I needed to take care of it. I went to fire up the saw and could barely pull the rope to turn the engine over. Flipped the choke a few times, tried to pull it over and same thing. I grabbed the old Makita 6401 and took care of the tree. When I got back to the shed, I pulled the cover off and pulled the plug out of it-it was soaked with gas. I pulled it over and a lot of gas came out of the cylinder. I pulled it over 5-6 times to get all the gas out of the cylinder, put the plug back in and it fired right up. What would cause this to happen? I have never seen this before in any of my saws. The shed does get hot during the summer, could that have anything to do with it or is it possibly a carb issue.

 

[hotshot]

Probably just a leaky inlet needle, and yes it can pump a fuel tank empty in a summer month. Pressure test the carb, it should hold 8# all day long.

If it bleeds down, pull the carb & needle, clean the seat, replace the needle, check the metering lever height & then retest.

The fuel tank vent duckbill valve (item 6 on the IPL) acts like a pump check valve during heating & cooling cycles. It allows vapor into the tank when it cools down at night , then allows the tank to pressurize when it heats up during the daytime.

EDIT: That saw’s under warranty, so have your saw shop fix it, unless you want to DIY.

 

[Bluemtn969]

Probably flooded from using the choke. I have a ms362 standard carb version and it will flood on choke unless it's below 55 F or thereabouts.my older saws (non strato) are much less sensitive.