merc 175 sport jet

[etech2008]

Hello,

I am working with a 2005 sportjet 175 it had low compression on cylinder #4 I pulled head and cylinder looks good exept really oily compared to the other 2 no scoring the piston has good side to side movement indicating that the rings are fine.

It is the style that has the rubber rings instead of head gasket it looked as though there was some exhaust leaking out but the ring itself looks to be in good shape.

any ideas??? Motor has never been overheated and has always ran fine still starts and idles good just loss of power do to that cylinder.

Also didnt see any evidence of water in any of the cylinders however I have seen many head gaskets blown without water in the cylinders.

thanks for your help!!

 

[Faztbullet]

Re: merc 175 sport jet

low compression on cylinder #4....piston has good side to side movement indicating that the rings are fine.

If compression is low it usually: rings, skirt of piston,reed,head gasket/o-ring.
I have never seen a o-ring head motor pop a o-ring even after they had been hot. Side to side play wont tell you any thing about ring condition other than that they are there that where a leak down test excells over a compression test. If its the grayish/blackish oil that unburnt fuel/oil and aluminum mixed and scuffing will be on bottom of cylinder on skirt and you should see some scuffing coming up the exhaust side of sleeve. This is usually cuased by chipped/broken reed or debris in carb....

 

[etech2008]

Re: merc 175 sport jet

thank you I am going to take it down. it does look like theres aluminum mixed in there ill see what is going on thanks!!!