Re: poppet and water pressure
The poppet opens at speed to let water flow through the motor faster. So, if it's open all the time, you have low pressure at idle, but it will cool going fast becuase it supposed to be open. If it's closed all the time, it will cool going slow but will show sky high (30 plus) pressure at speed. The only other poppet failure is the plastic ring in the block blowing out, that will cause sky high pressure all the time and will run hot at any speed other than at idle.<br />With all that behind us, lets look at other things. First, a pressure gauge that rises then drops to zero can indicate a gauge that has been damaged by freezing weather. I had one years ago that would show 6 PSI until it hit 3000 RPM and drop to zero. I have seen other strange readings similar to that. <br />Start from the start. Simple, but usually overlooked. Check the gauge with another gauge to reassure it's reading correctly. Pull the lower unit and check the water pump from the ground up. Check under the base, inspect all three gaskets, replace the impeller and check to make sure the insert is not spun in the housing. If you have a nose cone look for sticks and trash in the passages. Check the copper tube in the midsection and the rubber bushings on each end. <br />BTW, the thermostats will only make one run hot after a few minutes at idle, once you get over 2000 RPM the water bypasses them.
