Re: Johnson 3HP JW-17 Compression woes

[jerry-w-bert]

Got to this engine today .Ok , the top ring on the top cylinder only moves a little bit , not like the other 3 ,which depress about twice as deep . I was patient squirting more juice in every other day ,cleaning with carb clean and comp’d air. It never moved any more than from the first .But since it did move I put on the new head gasket following fleetwins instructions . I put head on my table saw and checked for warping by doing figure eights on fine grit emory paper. No high spots. Unfortunately I don’t have a torque wrench that goes down to inches so I just snugged the head down little by little going by the diagram . Compression is 55 bottom and 40 top … There is no way I don’t have that head on in a satisfactory way . I have not bothered to gas it up and try to start it with current Compression . The 55 number (bottom cyl ) was the same as before and now the top is down to 40 and not 45 . This supports 2 things , 1: the gauge is consistent whether perfectly accurate or not . So compression is indeed low . 2: My installation of the head appears not to be the cause of the low compression because the readings are fairly consistent both before and after this work.

I am looking for a torque wrench that will go down to inches since I will need it for the rods and etc to replace rings.

So it still appears that maybe rings are needed???, But I need expert advice . What would you do next? What do you think could be another cause of the extremely low number in the top cyl. ..This engine was running last year ,before I touched it ,so I’m really down about it… Help please!