Too Cool

[Bradley]

My Atomic 4 temp will not get above 120. Is there a way to pull the thermostat and test it? Could this lead to very fouled spark plugs?

Thanks

[Don Moyer]

If you have an original Holly thermostat (brass, with 3 small coil springs holding it together) you should be able to visually inspect the thermostat to determine whether or not the moveable part of the valve is permanently raised up off of the main part of the housing.

It's rather difficult to visually inspect the current thermostats from Westerbeke without a "breath through" test. When looking in from the top of the thermostat, the moveable disk may appear to be down and closing off the opening in the center of the housing, when in fact, it's raised off the housing by 1/16" or so. The breath through test is simply holding the thermostat in your mouth while you attempt to breath through it. If you can breathe through the thermostat normally, it is stuck open enough to cause over cooling.

A normal operating temperature of 120 should not result in "very" fouled plugs. Excessive fouling of plugs usually results from general poor health of the engine: low compression (70 or below), ignition system in need of tuning up, carburetor in need of cleaning, elevated exhaust back pressure, etc.

Don