1974 johnson 115 hp compression

[Jeremy27]

I am new to the forum,well sorta!Ive been reading posts for years just never registered.Anyways my question is ...I have a 74 johnson V4 that I bought a couple years back.Been a great motor for sure.Love the engine!Anyways I did a compression test today and got 90 psi on all heads.I was shocked cause last time I checked they were 115-120 psi.Now this is what I really dont understand...I checked again but this time with out the hose on the compression gauge, I used the quick connect with the rubber head that you press against the spark plug holes.....120 psi.Tryed the hose again,(checked my o ring on the fitting thinking that may be the problem but no) 90 psi?Anyone ran into this before?And which one should I go by?

 

[interalian]

Is it an old compression tester? Maybe the hose swells and steals some of the pressure, or it has leaks. I'd take the higher reading as gospel.

 

[Jeremy27]

The unit is actually only a year old and the hose has only been used 2 x!I agree with you though,the 120 psi .No matter how the pressure got there,,hose,pipe,ect.It put 120 psi in the gauge.The engine runs great.A little funny starting cold but thats normal with these motors,after that it runs like a top all day!