I have a pair of 275 hp turbo Lehman's in my 46 ft. trawler.* I had to rebuild one after running a valve through the engine, so I quickly changed the valves on the other engine.* I have heard these 275 hp engines have this problem.* What is the way to avoid this problem from happening again?* Will running the engines under 1800 rpm's help or will I have other problems running them at lower rpm's most of the time?* These engine's have low hrs. 1,000 hrs.* on them Thanks in advance for any help out there.....Roger