How much compression should an outboard motor have?
What Outboard Compression Test Results Mean. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke. Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI. Here is everything that you need to know about outboard compression tests.
Why do outboards lose compression?
Here are some of the major reasons that boat motors lose compression: Carbon clogging the piston-ring grooves. Engine could be worn out. Internal damage (a broken piston ring, for example)
What should the compression be on an outboard?
This source says modern two-stroke outboards should be in the 90 to 105 psi range. However if you watch the end my video below you will see that my 1979 Evinrude 6 Hp cranks easily cold (2 pulls) with 60 psi compression This source says the older two stroke outboards below 25 Hp should be between 75 and 85 psi.
What should the compression be on an Evinrude crank?
However if you watch the end my video below you will see that my 1979 Evinrude 6 Hp cranks easily cold ( 2 pulls) with 60 psi compression This source says the older two stroke outboards below 25 Hp should be between 75 and 85 psi. This source seems to confirm with my understanding that 60 psi in older outboards can sometimes be OK.
What should the PSI be on a 4 stroke outboard?
Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI. Here is everything that you need to know about outboard compression tests.
What should the compression be on a two stroke Yamaha?
Two-stroke engines should be somewhere between 100-120 PSI per cylinder. Then four-strokes are going to be somewhere between 150-210 PSI! This is where the throttle position comes in. On say a 250 HP Yamaha four-stroke. If you do a compression test, ( click here to learn how to perform a compression test.) and you have the controls closed.
This source says modern two-stroke outboards should be in the 90 to 105 psi range. However if you watch the end my video below you will see that my 1979 Evinrude 6 Hp cranks easily cold (2 pulls) with 60 psi compression This source says the older two stroke outboards below 25 Hp should be between 75 and 85 psi.
However if you watch the end my video below you will see that my 1979 Evinrude 6 Hp cranks easily cold ( 2 pulls) with 60 psi compression This source says the older two stroke outboards below 25 Hp should be between 75 and 85 psi. This source seems to confirm with my understanding that 60 psi in older outboards can sometimes be OK.
What causes low compression on a 15 hp Johnson?
It allows the rings to free up in the grooves so they more closely follow the cylinder walls. low compression is also cause from stuck rings, in there seats on the piston, debarbing removes the crap sticking the rings. it’s worth $10.00 to try it before tearing into the motor.
Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI. Here is everything that you need to know about outboard compression tests.