thermostat question

[oscar boy]

My outboard motor(Johnson 115 crossflow) has two thermostats and to poppet valves.<br />It seems the thermostats work at low speed and the poppet valves open when the pressure increases at higher speeds. When the poppets open and let more water flow through the motor, the temperaure drops and the thermostats close.<br /><br />I was told that when the poppets valves open the motor temperature will be about 25 degrees above the temperature of the water the boat is in.<br /><br />Is this is correct? If not how does the cooling system operate.

 

[Solittle]

Re: thermostat question

I have not heard of a 25 degree rule of thumb. You have the right idea sorta. The t-stats and poppets work together regulating both pressure and temp so that your block reaches and maintains the design operating temp. For most two cycles this is about 140 degrees (140 is what OMC calls for for my twin 110 crossflows).<br /><br />One of the best ways to monitor what your motor is doing (and hence to keep it happy) is to have both a temp guage and a water pressure guage. Look at both from time to time and keep an occasional eye on the pisser and an ear for the overheat horm. Motors like that.