What do you need to know about timing a Mercury outboard motor?
Make note of the timing belt, throttle cable, flywheel, spark plugs and idle timing screw. You must have a dial indicator and timing light to properly adjust the timing of your outboard motor. You will also be required to use some type of spark plug gap tool.
What are the firing orders of a 4 stroke engine?
From figure 4 cylinder #1 fires in the first 120 degrees. In the next 120 degrees (240 degrees), as cylinder #1 moves from the power stroke to the exhaust stroke, cylinder #4 fires. In the next 120 degrees (360 degrees), as cylinder #4 moves from the power stroke to the exhaust stroke, cylinder #3 fires.
When to set the engine to TDC on the exhaust stroke?
NOTE When setting the engine to TDC on the compression stroke for cylinder #1, you must realize that the crankshaft rotates twice for every single rotation of the camshaft. So, if you simply set the crankshaft to TDC without looking at the position of the camshaft, you may actually be at TDC on the exhaust stroke for cylinder #1.
When does cylinder 2 enter the power stroke?
Cylinder #2 is now on the compression stroke, cylinder #1 is on the intake stroke (i) and cylinder #3 is, as expected, on the exhaust stroke (e) to expel exhaust gases produced from the power stroke it just completed. See figure 3c. In the final 180 degrees of crankshaft rotation (720 degrees), cylinder #2 enters the power stroke.
Make note of the timing belt, throttle cable, flywheel, spark plugs and idle timing screw. You must have a dial indicator and timing light to properly adjust the timing of your outboard motor. You will also be required to use some type of spark plug gap tool.
Why is my Mercury outboard engine not firing?
It is starting and running, but the engine does not sound like all the cylinders are firing. It sounds like it tops at 4000 rpm instead of 5500 rpm. Only going 30, the cooling system is working ok, and it idles fine, just when trying to cruise it is not getting the speed it should. It is also slow off the line.
Where is the timing mark on a 2 stroke ignition?
After locating TDC, the mechanic should rotate the flywheel backward (typically around 2.0-mm vertically of the piston) until marks on the flywheel align, this is the timing mark and the point at which the contact points should begin to open.
Can a 2 stroke engine run at the wrong time?
If the timing is close to TDC (top-dead-center) it is possible to catch the piston just at the wrong time with the result that the engine runs backward. This problem can only happen on a 2-stroke because there are no valves to be operated in a set sequence, as in a 4-stroke engine.