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gvg_uwec

Where to start on a 15hp johnson

7 posts in this topic

This weekend my dad is bringing me up a 15hp johnson from down south for a gift, it used to be my grandpas but has not been used in about 3-4 years. The problem is the last time it was used was in saltwater and my grandpa was swamped in his small canoe like boat by a large boat's wave. I dont know if it was ever restarted or flushed.

Where should start when I receive it, do I pour a little oil in the cylinder and slowly pull it over to make sure the cylinder is not dry, or should I just hook up a gas line and just pull it over? What is your first move when attacking a motor that has not been run in a few years?

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flush it out, lube all of the linkages, some seafoam deep treat (seafoam in a spray can) down the carbs, pull the plugs take a look at them and probably replace them, pour a little oil in the cylinders and move the crankshaft, and finally take a look at the lower unit lube (change most likely). Assuming it turns over then I would give it some water and try starting it up. Depending on what happens then you'll know where to head.

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Its hard to tell what its going to need. Do as suggested to start, most likely the carb needs to be re-built at a minimum. If it was swamped, submerged and never flushed out (the powerhead) it may very well be your new anchor.

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Agreed... I would plan on re-building the carb, but I would maybe pull the spark plug first and pull on the rope until it gets close to TDC... see how much rust is on the face of the cylinder, or if you can turn it over at all.

Once you get it so it will turn over I'd run a compression test and see if there's any hope.

To echo Bruce's sentiments, if it was never flushed it could very well be rusted solid.

marine_man

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Update-

I got the motor this weekend and set it on the back of my boat. the flywheel turns over and so I thought for giggles I would hook up the gas to it and try giving it a pull. Well found out the carb needs a rebuild (expected) when I pumped the bulb. I plan on getting a rebuild kit and fixing the carb soon. Another question I have is that the bolt heads on the head itself are rusty and corroded. I would like to replace them if possible. Do you think it would be okay to remove one at a time if possible and put in new bolts without breaking the seal on the head gasket. I dont have a compression tester right now but if the compression is good should I even bother with replacing them?

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If there is no other reason than they are rusty, I'd leave them alone. You risk breaking them during removal if they are frozen.

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I wouldn't take out the head bolts unless you have too. Assuming you have decent compression then there shouldn't be any reason to do so. I would give them a shot of penetrating oil every once and awhile though.

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