1999 DT150 Oil Fouled Plugs

[backwoods]

We are having a discussion around the docks about a problem with a 1999 DT 150 EFI. The owner has removed the thermostats at some point months ago and is having issues with the motor not idling. When you pull the spark plugs they are oil fouled. The motor runs great at high rpms but will only idle for 5 minutes or so without slowly choking out. I think the lack of thermostats is not allowing the cylinders to reach normal operating temps so the oil is less likely to combust.

any thoughts?

[Egorena]

1999 DT150 Oil Foulded Plugs

Exactly! Remember, you have an open cooling system that runs cold water thru constantly. That water never gets real hot, thus the oil doesn't combust properly to begin with and worse without a thermostat.

[backwoods]

1999 DT150 Oil Foulded Plugs

That was my thought. What else would the thermostat be for? Boats aren't like cars where they need the warmer water for a heater! He just couldn't imagine how the cooling system would have anything to do with performance. thanks for your input. That got me $20.00!