lock nut...what lock nut(valve adj merc 3.0)

[watermellonI]

i have a valve tappin when get boat on plane and open the boat up but when i idle down its hardly noticable, so i read here about adj valves, and there are no lock nuts that i can see, there is a nut in center of rocker but no lock nuts, Im guessing these are just hydraulic and you have adjust while running? Im trying not to do that and read here that you can

 

[wncrjb]

Re: lock nut...what lock nut(valve adj merc 3.0)

I'm not sure on newer 3.0's but on my older one ( 1988 ), the nut in the middle of the rocker arm is where you make your adjustment ( I think it's a 5/8 socket ) and it also acts as the "lock nut". If you want to adjust it while running, tighten the nut in small increments until the "clatter" stops, then tighten another 1/2 to 3/4 turn to preload the lifter. Make all valve adjustments very slowly, no more than 1/4 turn at a time and then remove the socket and give the motor a few seconds to compensate before making the next adjustment. If you must turn the nut more than a few complete turns, you may have a bad lobe on the cam, bad lifter or bent push rod etc. Adjusting valves with the motor running, and if you have good oil pressure, be ready to take a bath.

 

[Reel Poor]

Re: lock nut...what lock nut(valve adj merc 3.0)

Make sure there is not too much oil in the engine. High oil levels can cause the oil to be aerated by the crankshaft which can cause the symptoms you're describing. Also be sure there is no gas in the oil.

 

[watermellonI]

Re: lock nut...what lock nut(valve adj merc 3.0)

thanks wncr, i m tryin to avoid doin it that way, and i did finally find it in my manual, (i posted cause i found everything but adjusting valves) Reel Poor, the first thing I did when i got in there was smell the oil, and all is good, oil level was good also, when i got to the cover itself all the bolts were loose, seal was good to the head, no leaks, had to tap it loose with a mallet.
I do have a question for you though, my manual says take out lash and then 3/4 turn I remember reading a post or two(yours maybe?) that said a full turn after lash so which?
ps lots of respect for you read lots of your posts
thanks

 

[Reel Poor]

Re: lock nut...what lock nut(valve adj merc 3.0)

3/4 to 1 turn from zero lash is all good.

 

[watermellonI]

Re: lock nut...what lock nut(valve adj merc 3.0)

10-4