Re: Cooling Question: SOLVED!!!
I apologize for reposting this topic, however, Don S has kindly posted the links so that you can read what I have done in the past to try and correct this problem. Thanks Don.<br /><br />I have a raw water cooled system, no heat exhchanger involved.<br /><br />Basically, I cleaned all manifolds and risers with muriatic acid and flushed them out with a high pressure water hose to check for flow. The flow through all risers and manifolds was great, flushed out all debri and had good clean water. I then replaced the entire thermostat housing, thermostat, and all cooling hoses from the transom all the way through to the exhaust/water exit from the risers.<br /><br />Timing checked out good for what I could make out on my balancer. I could not check the advance due to not being able to read the numbers etched in my balancer. However, running at idle and quick acceleration are great. No hesitation whatsoever.<br /><br />With all things above replaced I went out on a test run and with the thermostat in place, the temperature reaches 200 very quickly once on plane. It is fine at idle. Which led me to beleive I had a flow restriction somewhere, and sinice I had cleaned/replaced everything from the inlet side of the thermostat housing, I checked the flow from the transom hose. The water flow from that hose seems great to me. Holding the hose vertically I have about a 2 inch column of water at idle and about 3-4 inch column at 3000 rpm.<br /><br />So I committed the cardinal sin of cooling and removed my thermostat to see what affect that would have. Without the thermostat I can run at 3700 rpms at about 160-170 degree F, continuously. After a hard run I might climb up to 180 or so but cools back down if I rev the engine up in neutral. Then I changed props from a 19" to a 17" pitch. That helped me reach a higher max rpm of 3700 and the engine ran a steady 160 without the thermostat in place. I figured that without the thermostat in place it should run well below that....I figure around 100-120. I have a 15" prop on order to help me get into my WOT rpm range, so this may help with my temperature as well. Can only hope at this point.<br /><br />While running on the muffs without a thermostat the temperature doesn't get above 120 and I have flow from both idle releif ports at the transom. I just want to get this corrected so I can run the proper setup.......with a thermostat installed and a running temp of about 160-170 at WOT. <br /><br />I guess one thing I can check is to see if I have any bubbles in the flow from the thermostat housing to the exhaust manifold.<br /><br />Sorry for the long post, just wanted to get everybody up to speed.
