OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines GXV390 Smoky at startup

Hi, my grandson was helping me the other day to mow a lawn, I told him to check the oil and top it up if it need it. I then saw smoke coming out of the exhaust when he was using it. I stopped him and checked the oil and it was over full by about a litre, I removed the excess oil and restarted mower, was fine then. Now tho when I startup first time it blows a large cloud of blue smoke, it then clears and it fine untill you stop it and leave it for a few hours and it will blow smoke. If you restart after 10 mins no smoke.
Any idea what it maybe.
Thanks

Hi David, welcome to Outdoorking.

After running that mower in an over-filled condition there will be oil in the crankcase ventilation valve and through the breather hose. Some of that will have to be burned rather than draining back into the crankcase. My guess would be that may be what is happening. If it had a litre too much oil though (i.e. about three times the correct amount of oil in it) there will have been some pretty ugly solid chunks of liquid being violently hurled around in there when it was running and it is possible that damage has been done. It wasn't designed to pump solid oil like a hydraulic pump, and on the underside of the piston and rings at that.

I suggest you watch the oil level carefully - even a very small amount of over-filling, due to checking the oil on ground that isn't quite level, can result in oil being blown into the breather system every time you run it.

Hi Grumpy,

Thanks for that, I was estimating a litre it may have been only 1/2. Yesterday I decided to pull the air filter housing off and cleaned it out. I also replaced the Air Filter. I started it up last night and no smoke, will try again later on today and see if it blows any smoke. It may have pumped oil back up the air filter and housing. Will keep you informed. Thanks