atv question

sal64 · May 10, 2015

HELLO ALL i have an old atv 1986 honda sx350 the atv runs good plenty of power put after i drive it a few times about 30min and shut it of it wount start becase the plug is fouled it has carbon on it not oil i clean the plug and it runs fine again this has been happening for a few yrs now but its getting worse also the oil is very milky any idea what is causing this?tu.

PHPaul · May 11, 2015

Milky oil is usually an indication of water in the oil. This can be either from a leak allowing water in from the atmosphere, or condensation. Condensation is usually the culprit if the machine is run for short periods and rarely run long enough to get the oil good and hot and boil off the water.

Sounds like the plug is fuel fouled. Running too rich either due to a mis-adjusted or worn carburetor or a plugged air filter.

Sodo · May 11, 2015

Carboned up plug suggests the fuel mixture is too rich.

Maybe you're running it with the choke "on", which on a Honda is usually "up". If choke's NOT "on" maybe the richness is caused by plugged air filter, too much resistance acting like a 'choke" & sucking too much gas. You might take a look at the air filter. On a machine 30 years its possible that there is no air filter at all, the foam may have disintegrated and all sucked thru the engine :shocked: YIKES! I've had this on a 1997 Honda yours is 11 years older.

Don't run it with milky oil, change the oil. Don't fuss about oil types just get some clean oil in there. And take note if the new oil becomes milky.