Re: Johnson 150; Safe buy?
OMC made thousands of these engines over the years. They were extremely popular. Made good torque and hp, but were considered fuel thirsty. Parts are still readily avaliable for them. Is this a straight 150, or the higher performance 150S (GT) model? You are right on regarding the compression issue. Good compression is an important key to determining overall condition of the powerhead. Check it or have it checked prior to purchase. Smooth idling and ability to run high speed validate the condition of the carb passages and the fuel pump, even the ignition system. You should drain some of the oil from the lower unit and check for water intrusion-you should expect to see clear oil inside, not milky. Check for leaks around the powerhead, either exhaust or water, even fuel. If you have a laser temp gun, check the cyl head temps when running at idle, should be in the 145-155 range. Check the power trim for operation and use the boat's voltmeter to try determine if the engine recharges the battery. Any receipts from the prior owner will give you an idea of the maint. which has been done over the years. I'd probably have the impeller replaced upon purchase unless you know it was recently replaced-something that will give you peace of mind as a new owner. You can get original service mannual from Ken Cook co. in Milwaukee-you can call them or access them on the web. Parts lists for this engine are available at epc.brp.com
