needs to be over 105 to run ideal is 120-130 stock higher if modified
You have to take out the cylinder, how low is it, what is the difference
The crank case is the bottom end of the motor. This fills automatically upon running. The motor oil suggested for a Polaris 4 stroke motor is 0W-40.
Polaris four stroke oil is a 0-40w synthetic.
Because both valves (or reeds in the case of some 2 stroke motors) in the cylinder head are closed and it is compressing the air and fuel i so the mixture will ignite and cause combustion or firing of the mixture to create power to cycle the motor through the exhaust and into the next compression stroke.
When installing a distributor in a motor, the rotor button should point to the terminal of the ignition wire for the number one cylinder at top dead center (TDC) on the compression stroke. This ensures that the ignition timing is correct when the distributor fires. It's essential to confirm that the engine is at TDC on the compression stroke, not the exhaust stroke, for accurate timing. Proper alignment ensures optimal engine performance.
Bad compression is usually worn out piston rings, no compression is usually bad valves - assuming it's a 4-stroke.
125 is the least
Number 1 cylinder, which would be the first cylinder on the drivers side of the engine. You want the rotor pointing towards the 5 O'Clock position looking at the distributor from the front.
http://www.bikebandit.com/houseofmotorcycles/polaris-atv-sport-400l-w968540-1996/o/m5503
To find the terminal on the distributor cap for the #1 sparkplug on this engine turn the engine by hand and find top dead center (TDC) for the compression stroke of the #1 cylinder. This is accomplished by removing the #1 cylinders spark plug ( # 1 cylinder is the one toward the front of the car on the drivers side of the motor ). Rotate the crankshaft by hand and listen to hear the air escaping from the spark plug hole. On the compression stroke the hissing will be louder than on the exhaust stroke. If you aren't sure take off the valve cover and observe the valves as you turn the motor; both will be closed on the compression stroke but on the the exhaust stroke on will be open. When you find TDC for #1 the rotor will be pointing almost directly at the #1 cylinder. Put the distributor cap on and the terminal the rotor would ignite at that point is the one to put your #1 sparkplug wire on.
Yes, All Subarus are "wasted spark" systems where two cylinders fire at the same time, but only one is on the compression stroke while the other is on the exhaust stroke, thus the spark is wasted.
Compression in a Johnson 25hp outboard motor refers to the pressure created in the combustion chamber during the compression stroke of the engine cycle. It is a critical factor that affects engine performance, fuel efficiency, and overall power output. Proper compression ensures that the air-fuel mixture ignites effectively, leading to smoother operation and better acceleration. If compression is low, it may indicate issues such as worn piston rings, damaged gaskets, or cylinder wear, requiring maintenance or repairs.