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Merc in line 4 1985 tap noise 140hp 30l

dive7mmwet

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"Have a 4 cyl merc did a compr

"Have a 4 cyl merc did a compresion test-
#1 120
#2 125
#3 112
#4 125
Did a second oil flush & filter = no change with sea foam, oil now is 30W per manual
tested under power in water still tap /click.no change, seems not to be exhaust,,,

Did a warm engine valve adj loosen till rattle and 1/4 turns in slow! til 5/8 to 1 full turn down no change,
Next step??
Is it time to pull push rods and inspect and Hydraulic lifter cover and look at? trying to track sound is hard used a hose ,screwdiver and it seems to be in front and top end-but I cant hear a darn thing any hoo!
Thanks for any ideas so much!
Brad"
 
"Is this "tap" noise a

"Is this "tap" noise at Idle or all the time?
Those 3L motors had a cam gear hub problem, the cam gear hub would become loose from the fiber gear and make a noise like piston slap at Idle. it would go away under load and return at Idle.
I think there is a service bulliton back in the 80's about this problem.
good luck.hope this helps."
 
"The engine GURUS can give you

"The engine GURUS can give you more info; here is my WAG.

What engine is it? Did you do a wet comp. check? Did results increase? A collapsed lifter will make the noise you described and it will be loud at idle. After running a while and stopping the engine for 10-15 mins.; does the noise dissappear when you restart? Yes; lifter is dead; it won't hurt the engine but is annoying. Your compression readings are not too far off; the one low one should be checked again at the end of the season.

If the noise is more of a rap, rap, rap... and does not change but keeps up w/engine RPM, I would suspect a carbon buildup on a piston. Merc. makes a decarbonizer spray for its engines. Try it 1 or 2 times per directions."
 
"Allan & Guy Thanks,
It&


"Allan & Guy Thanks,
It's a tap/click it dose not change from cold to warm, it seems to float away if you rev engine a bit but is a click click click at idle and under load pushing boat high or low speed the click keeps up with revolutions at like 1300 rpms it kind of quiets down but at higher rpms comes back and low rpms (Idle)
I am going to dig into the lifters first then maybe the fibre gear then pull the head,
Brad"
 
Brad
Fuel pumps have been kno


Brad
Fuel pumps have been known to give off quite a click if the spring goes wonky in them.
Bert
 
"thanks,I am going to pull the

"thanks,I am going to pull the lifters and replace,cheap first shot-next head.will update on find."
 
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