old 6 inline merc. compression ?

[pull-do]

Need to check the compression on this motor, old merc 6 inline, 4 carbs,,, the carbs are currently off the motor, since you have/ need to check comp. at WOT, seems like I could do it with the carbs off and the carb bore open to atmosphere,,, don't want to put the carbs on if I don't have to.

Thanks,,,

 

[Chris1956]

Re: old 6 inline merc. compression ?

You can check compression with carbs off. As long as the reed valves are still installed. You sure you have 4 carbs?

 

[jimmbo]

Re: old 6 inline merc. compression ?

probably a typo. I have seen inline sixes with 6 carbs. If the reeds are not installed it is unlikely the crankshaft or the pistons are either.

 

[pull-do]

Re: old 6 inline merc. compression ?

My bad,,,senior moment, it has 3 carbs, it's my daughters boat but I still should be able to count to 3 , thanks for the info and replies.

 

[pull-do]

Re: old 6 inline merc. compression ?

Well did the compression test,, very surprised at the outcome, lowest was 135 highest 145, sounds like a sound motor to me,, on to the carbs now, this is a 115 hp.

 

[pull-do]

Re: old 6 inline merc. compression ?

Hit a dead end, for me anyways,,, the carbs, I can't find any OEM kits, anybody here on this site use the Sierra kits sold on this site, pretty good quality?

 

[Chris1956]

Re: old 6 inline merc. compression ?

Sierra and some others are fine. OEM kits should also be avail. Replace gaskets, inlet needle and seat and floats......Adjust as per spec in Service Manual.