I just bought a used Johnson 18 HP outboard, and wonder if it has a cooling problem. As best as I can tell, the model number is FD13R. Might be FD18R. Not sure how old, but I'd guess '70s or '80s. My concern is about the way the water is spitting out the exhaust cooling port. I'd think it should be a fairly steady spitting, but this is the way it occurs: when I first start the engine, it spits for a second or two...then it stops for maybe 30 seconds or so...then it will spit a lot of very hot water, pause a second or two, then another long burst of water...then it will start spitting a fairly light, but steady spitting. When I shift into gear, the spitting stops for a bit (maybe 10 seconds), then I get the heavy spitting, then it stops for a bit, then heavy, then fairly light but steady. IS this normal? Or should it be a more steady spitting? <br /><br />I really don't understand how the water is supposed to move or else I'd maybe know if it is normal for it to behave this way. Can someone explain briefly, what the principle is for how the water moves? Ie. is it by some type of impeller (in which case I'd think it should be steady). If by impeller, what drives the impeller? So it move by a pump? If so, what drives the pump? Ok, I think that pretty much covers it. Do I need a major repair, or is this something that maybe can be repaired with a good service manual and a good auto mechanic who is just starting into the boating scene?<br /><br />TIA,<br /><br />Rob
