81 Johnson 90hp re-ring/low comp help

[smoedog]

So I picked an 81 johnson 90 horse v4 last year and had it out once. it ran alright other than dropping a cylinder (bad coil pack) every once in a while.

I had a finicky idle and hard to start without giving it a lot of gas.

Did a comp test and had a wide range of readings from 80 down to 30. So I was going to re ring it. Pulled the head and the bores look great with no damage to the walls or the pistons so I figured I could get away with a re ring.

I did this on a previous force 50 i had by pulling the carbs and reed plate and getting to the connecting rides from the back side. I just did this on this johnson and it is not possible. I already know the answer but anyone have any other way of getting the pistons out without removing the powerhead and splitting the block? A lot more work than I wanted for a boat I have to sell.

 

[flyingscott]

Nope You might check you heads see if they are warped or a bad head gasket. Otherwise you have to tear it down

 

[racerone]

I would be surprized if there was no " damage / wear on cylinders " here.-----And lining up the connecting rod cap would be impossible to do without the crankcase cover off.----But everybody works to different standards I suppose.

 

[emdsapmgr]

How did the seal rings on the two head gaskets look? Were the compression seal rings damaged at all,-warped? If so, replacing them could be a cheap fix. I'd be looking for compression on a rebuild 85 of that year to be in the 125 lbs range if it has the tight heads 324528/529. OMC changed to the low compression heads mid-year in 81. If you have the low compression bathtub heads, the compression might be in the 90-95 lbs range normally. Those low compr heads are p/n 326503/504.