I have a 135 hp fitch 2003 I have been trouble shooting the engine because a no oil light comes on.replace oil pick up pump, primer ball ,looked for leaks, step by step as solec manual describes. But can't find no where how much oil pressure should be.. My pressure swith operates in the range of 50 to 53 psi. My system is producing 38psi at idle. Any insight will help thanks.