compression #'s (?)

[NaWater]

1996 ocean pro 115 (evinrude). compression as follows:<br /> #1 cyl.- 132, #2- 125, 3- 134, 4- 115. boat runs fine, idles fine, tach's out to 6100rpm w/ light load and current prop. (i know i could use more prop.). question is: how much do i need to worry abt. that #4 cyl.?<br /> thanks for any help/input.

 

[NaWater]

Re: compression #'s (?)

oh yhea. i will be fogging/decarbonizing it tomorrow. what should i be looking for in an improvement if its just a ring prob.? is there a percentage (10%, ect.) increase in compression to look for?

 

[Hooty]

Re: compression #'s (?)

How much good the decarb does depends on how bad the carbon build-up is. If the engine 's not coked up, you'll see no improvement.<br /><br />c/6<br /><br />Hooty

 

[NaWater]

Re: compression #'s (?)

yhea, just hoping it would be a ring problem. thanks for your input.<br />i'd still like some input on how much i should be worried (if at all) about running w/ that #4 piston at 115(?).

 

[G DANE]

Re: compression #'s (?)

NaWater<br /><br />How do you number your cylinders ?<br /><br />If you got on first starboard bank: 125 and 115<br />and then on port 132 134 <br /><br />Your compression then is within 10%, as my manual says not to compare too much between banks and you should be fine.<br /><br />Someone else jump in here - I think this guy maybe just needs a decarb and then he´l be fine ?

 

[Jack Shellac]

Re: compression #'s (?)

The OMC manual says they shouldn't vary by more than 15 psi. You are close and the decarb may get you even closer.

 

[NaWater]

Re: compression #'s (?)

i've got #4 piston at "lower port" side. i'm hoping the decarb will put me back w/in spec. thanks alot guys.

 

[ledgefinder]

Re: compression #'s (?)

Why is it always #4? <br /><br />Hit #4 heavy on the decarb (port throat of bottom carb). It the decarb doesn't help, suspect lean condition on #4, due to junk in the carb. You MAY have caught it early enough. Do you run an in-boat (permanent) fuel tank?<br /><br />Don't change your prop, BTW, sounds dead on.

 

[NaWater]

Re: compression #'s (?)

yhea, i do run perm./inboat tank (w/ in line fuel/water separator). thanks for the advice on the decarb. i did plan on giving that #4 a little extra shot. i'll pay that carb. some mind too (lean cond.). thanks alot.

 

[Dhadley]

Re: compression #'s (?)

What is "perm."? Lets hope its premix and not premimum. <br /><br />Let us know how you make out!

 

[NaWater]

Re: compression #'s (?)

"perm." meaning "permanent" fuel tank...in reply to ledgefinders previous post. i do not use premium gas (thanks to your ((as well as others)) previous posts on that subject). <br /> and as soon as i can get out of this "salt mine" for the day, and get to the job at hand, i'll be sure to let you know how things turn out. thanks for the concern (and your knowledge and input on this board).