[THEFERMANATOR]

86 150 EVINRUDE will be a cross-flow engine and have a bubble back exhaust on it most likely. The looper engines will have a one piece block whereas the cross-flow engines will have plates that bolt onto the sides of the cylinders and the exhaust will also have a plate bolted on it between the 2 heads. The main thing to look for is that all the cylinders are the same or within 5-10% of each other. Normal compression on that engine should be in the 90-100 pound range on a fresh tight engine, but years of use and carbon build-up can and most likely will change those numbers.