90 pounds of compression good or bad?

[shannoninark]

i have a 86 johnson 175. i have narrowed a problem with a cylinder firing down to a bad <br />coil. i just checked the compression and came up with 92-97 on all cylinders. is this good or bad?<br />also, what is the best manual to get for this motor? chiltons, ect.<br /><br />thanks<br /><br />shannon

 

[Hooty]

Re: 90 pounds of compression good or bad?

Hey Shannon,<br />The 92 - 95psi compression is probably o-k. Just so they're within 10psi of each other is the criteria.<br />I think the Chilton is the best after-market manual but if it was me, I'd get the factory manual.<br /><br />c/6<br /><br />Hooty

 

[shannoninark]

Re: 90 pounds of compression good or bad?

hooty,<br /><br />thanks so much, i was told that the motor was rebuilt but i guess they forgot to tell me that it was rebuilt in 1989 lol. i guess the compression should be about 120 or so right??

 

[Hooty]

Re: 90 pounds of compression good or bad?

Not necessarily. A lot of things influence compreession readings including the gauge you use, engine hot or cold, oil in cylinders, etc.<br />How long since it was de-carbed?<br /><br />c/6<br /><br />Hooty

 

[shannoninark]

Re: 90 pounds of compression good or bad?

hooty,<br /><br />i really dont know how long it has been. from what i can assume it was last may or so. i will test the coil tomorrow morning. i am pretty confident that is it. i hope it is. i thought i got a honey of a deal...86 19' skeeter and 175 johnson for 1200.00 it had a bad lower unit and i replaced it with the idea that the engine was fine as a fiddle, i seem to have been a little duped.

 

[Hooty]

Re: 90 pounds of compression good or bad?

If ya can keep your knees together 'til you get a manual, it'll help you figger out if you have a bad coil or something else. Here's the place for a factory manual.<br /><br /> http://www.theoutboardwizard.bizhosting.com/parts_service_and_owners_manuals.html <br /><br />g'luck & c/6<br /><br />Hooty

 

[shannoninark]

Re: 90 pounds of compression good or bad?

sounds like a winner hoot. will order the book 2-night. i will keep you posted

 

[Hooty]

Re: 90 pounds of compression good or bad?

...and if it's has been a while since a de-carb, when you get it running, go ahead and give it one. Won't hurt a thing.<br /><br />c/6<br /><br />Hooty