1984 mercury 115hp question

[bolted4]

A guy is selling a 115 inline 6 motor will start fine on trailer, in water has some trouble starting, once started runs fine in water, says max rpm is about 4800, but should be 5200? He has mention the woulds timing acouple times. What do you guys think is there anything I should check in particular? How much is a compression tester? What thread do I need for this compression tester?<br />One reason I am interested in motor is I have a 82 with blown power head, so I have some spare parts. Any help would be greatful. Or anyone in Massachusetts, NY area lookinf to sell a good running motor, looking for 100 to 125 hp.

 

[Kenny Bush]

Re: 1984 mercury 115hp question

Get you a compression tester at your local auto parts store for about $20. Unplug all of your spark plug wires off the plugs. Disconnect the fuel supply. (We do this so it will NOT crank up on you). Move the warm up lever to wide open. Then one cylinder at a time: screw in guage/hose into spark plug hole, then turn motor over with starter for about 3 seconds, then record results. Repeat for each cylinder. If at all possible, please do this test with the engine warmed up prior. Your readings should be within 10% of each other, at around 120 lbs. Once you have established that the powerhead is good and balanced, then move to ingnition timing and fuel. Do a compression test and post results......