can anyone give me crash course on how to get one of these running, or if you know of any good repair manuals . my uncle just bought the boat and he wants me to get it running but i know nothing about it. it doesnt look like it has ran for a while but what can i do to see if it even runs?
Is this a Mercury 1150 or 115? If I remember correctly, the 1150's required higher octane fuel than can be bought at the gas station. I don't know if this is absolutely necessary, but you should confirm this before you try starting it.
First, make sure the air cleaner is clear of wasp nests and the like.
The next thing to do is check compression. This can be done in several ways with varying levels of precision. BTW, this is a convenient time to replace spark plugs if they need to be changed.
1. The easiest way is to pull all of the spark plugs (marking the wires so they will go back to the same cylinder if they're long enough to be crossed) and hold your thumb over each of the spark plug holes while someone turns the engine over. If you feel air trying to rush out during the compression stroke, you're already halfway there to confirming the engine will run.
2. The best way to check compression is to use a compression tester. These can usually be borrowed from an auto parts store. They're not expensive and make a good addition to a tool set for just such an occasion. You'll want to check compression for each cylinder and record the pressures from each cylinder. I was always told that the maximum difference from the highest to lowest pressure should be 25psi or less. I don't know what the pressures should be, but if the engine turns over smoothly and there isn't much variation in the numbers, you're probably OK. Someone will come along later and fill in the blanks for you.
Once that's done, check out the carb and ignition system for obvious defects. If you don't find anything, connect a water hose to the lower unit using some "earmuffs", put some fuel down the throat of the carb (just a few drops only), and try starting it.