I am trying to get my 98 Seaark zx200 and 98 Johnson 150 (model J150ELECD serial # G04476190) tuned up and setup. The boat if you are not familiar with it is a 20ft aluminum boat. The hull weighs around 1015lbs. The motor came with a raker 24p 14-1/2 dia prop. At WOT with 1/2 to 1/4 tank of gas (28gal tank) and about 600 lbs of two pasengers and gear I am getting 4500 to 4600 rpm. My top speed is around 50.5 mph GPS. So here is my question, what WOT rpm should I shoot for? I purchased a factory service manual and it gives a WOT range of 4500-5500 rpm and says the power is rated at 5000 rpm. Is 5000 rpm where my motor is going to make peak HP? I have read that around 5800 rpm is ideal and also that 4500 rpm is too low and lugging the engine and will cause premature wear. Maybe those reccomendations are for a different model engine? Based on advice in other posts I did a compression test this weekend and got 100-105 psi on all 6 cylinders. Any help would be appreciated.
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