Ok, been a while and still playing with this issue. Making progress but now runs 175+. Since last shared, my initial concern was lack of water flow out of exhaust at the bottom of the gimbal housing area. I put in the new molded hose at the transom through the gimbal housing using the aftermarket unit with stainless fitting at transom. It is not kinked either while out drive goes up/down. In fact, I have verified water flows very well out of sea pump by pulling hose at feed side of p/s cooler. It also flows well at top of exhaust elbows when I pull these while running. Verified both on garden hose and in lake. Pretty convinced no blockage through coolers. Also removed the water distribution manifold below the front of the engine to verify not plugged or corroded, fine. Removed from boat and blew water through most external hoses - to/from sea pump, from T-stat housing to bottom of both exhaust manifolds, from manifold under engine to bottom of exhaust manifolds where they push water up to the ball in the fitting. All good and clean. Then, I replaced the T-stat. Only 3 yrs old. Put both new and old in pot on stove. New one opens a bit sooner and opens more than old one, but old one certainly opened. Thought that was it. Then I decided to replace the exhaust manifolds and elbows. They were reported new when I bought the boat 7 yrs ago and were cheap aftermarket brand. Keep in mind, boat was used in brackish water for 7 yrs prior, but only fresh water since I've owned. New everything, gaskets, hose and ball fitting at bottom of manifolds and fasteners. Also new exhaust shutter valves as they were totally burned up. Water now flows through manifolds and out the exhaust at gimbal housing. Elbows cool to touch - again on ear muffs. Thought everything was fixed!
Took boat 4 hours to lake for this weekend. First 1/2 mile is no wake, so idling and temp goes to 175 and a little higher. Got up on plane and cooled off to about 170 for a bit, then went over 175. Sitting in lake, both elbows are quite hot to touch. Stat housing very hot to touch. What's going on??? Got boat back to rented slip while maintaining 175 and let sit over night. Fired up this morning and rechecked water flowing well at p/s cooler inlet and feed to both exhaust elbows.
Thinking now might not be generating enough water flow throug engine recirculating pump. Removed engine drive belt and pump turns very easily in both directions. Surprisingly easy. No thumping or noise as if bearing went out. Weep hole is dirty looking, no evidence of seeping water. Was able to stick pointed end of a zip tie about 1.5 inches into weep hole. All is dry around pump. Pump looks original to me. Paint over bolts and stud threads. Can the vanes in the pump corrode over 14 years and 565 hours so they no longer pump the required volume? Going to look for a recirculating pump today. With what I've spent already, another hundred or so is small to rule this item out. Most parts used are Mercruiser brand. Barr Marine manifolds and elbows. I'm very conscious of my work and cleanliness. Torqued all manifold fasteners, etc. This problem is getting the best of my 40+ years working on vehicles and engines! Any ideas?
Thanks,
Steve Kelley