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Updated 4/22 Rebuilding 2004 Mercury 9.9 HP 4 cycle with some problems. Any ideas would be welcome.

jmartinroe

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I acquired a 2004 Mercury 9.9 HP. Not sure if it starts and I don't have a gas tank for it.

It has sat out of the water for 4+ years and was sitting on a boat in the water for about 12 years with little use, as can be seen for the condition of the lower unit that it was left in the water.
I cleaned the engine and remover the spark plugs. As you can see from the pictures may not be worth perusing.
The oil looks brand new, I haven’t checker the lower units oil until I make a stand for the engine. The gas lines and filter are dry.
The spark plug that is badly corroded with oil is from the lower cylinder. I am hoping that there was maybe to much oil in the engine.
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Came from a club with a bunch of rich boys that just spend money. The marine mechanic said it would be better to buy a new one instead of paying him $95/hour to rebuild it. I retire in a year so it will become one of my projects.
I live inside the Perimeter near Spaghetti Junction.
Thank you,
Jeffrey
 

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That plug looks like it just needs changing. It's a 4 stroke so maybe one of them guys mixed oil in the gas not knowing. If it turns over, you probably won't need much. Unless a mouse got hungry and had a thing for wires. All kinds of videos are on YouTube. Before you fire it up, make sure the water pump is still there. Take a side intake plate off and see if any rubber's in the ports. I do have a new 3 gallon Merc fuel tank I'm not using.
 
The engine turns over easily. They have 7 engines, and all are 4 cycle so I would guess that they are only using Ethanol Free Gas on all engines. If they ad used a mix with this engine I would think that both spark plugs would be fouled.
 
From an engine left sitting down in the water for about 14 years. Well I wasn’t supposed to start in on it for about a year from now but…
Measured the compression on both cylinders. Cold and just pull start by myself. Top was 72 a bottom was 62. Both should improve a little. From what I could tell the head looks ok.
Took the fuel pump apart seems ok.
Got the carburetor to choke and change smoothly, didn’t rebuild yet.
Finally got the lower unit off. One of the three bolts broke in two. Not sure I can get the threaded end out of the lower unit.
This is all the corrosion around the water pump.
Need to let it sit for a while.
 

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