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 is good compression for a 9.9?
I’ve got a 1986 9.9 and the compression is 105 and 107. I recently got rid of a 1977 9.9 and the compression was 110 in both. Re: What is good compression for a 9.9?
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.
I’ve got a 1986 9.9 and the compression is 105 and 107. I recently got rid of a 1977 9.9 and the compression was 110 in both. Re: What is good compression for a 9.9?
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.
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 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 compression be on a Yamaha?
The compression you should see will vary with the make and model of the motor. 100psi would be very low for most normally aspirated motors. I see 155 psi on older Johnsons and Evinrudes, 130 is typical on many Yamahas.
What should my compression reading be on my engine?
Compression test results will vary depending on what kind of engine you are working on. Mainly, there is a big difference between Two-Strokes and Four-Strokes. As we stated earlier at the beginning of this article. Two-Stroke engines should have a compression reading of around 110-130 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’s the compression range on a Mercury cylinder?
For instance, a fully functional Mercury 25 Hp cylinder compression value may be significantly different than that of a Johnson 25 Hp. Its also rather hard to find where a manufacturer will say the compression range should be from this psi to that psi.
The compression you should see will vary with the make and model of the motor. 100psi would be very low for most normally aspirated motors. I see 155 psi on older Johnsons and Evinrudes, 130 is typical on many Yamahas.