Removing piston from Johnson 115 v-4

[kam4]

Hello,<br /><br />Have 1996 Johnson V-4 60 degree loop charged "Ocean Runner" model J115 SLEDR. I have 90 psi on #4 Cyl. with 130 psi on others. Removed head and find no apparent aluminum wipe or scuffs on bore but suspect rings were wiped from overheating. <br /><br />Is it possible to remove connecting rod caps and #4 piston by gaining access thru intake without pulling entire powerhead???<br /><br />Thanks,<br />Ken M.

 

[Dhadley]

Re: Removing piston from Johnson 115 v-4

More than likely the rings are just coked up. I'd do the Engine Tuner treatment first. Might save a lot of time.<br /><br />But to answer your question -- no, it has to come off. No big deal. Its a very simple design.<br /><br />Good luck!

 

[kam4]

Re: Removing piston from Johnson 115 v-4

Thanks for the input. I did work over the piston with an assortment of cleaners to see if it was only a stuck ring, but the compression was the same when I put it back together. Was hoping for a shortcut, in that the motor is of low mileage and very clean internally, except for #4 Jug.<br /><br />Ken

 

[Dhadley]

Re: Removing piston from Johnson 115 v-4

What do you mean by a variety of cleaners? I know you dont mean 409 but did you use Engine Tune and as per the instructions?<br /><br />Let us know!

 

[kam4]

Re: Removing piston from Johnson 115 v-4

Did use Mercury's brand of engine tune as per instructions as well as carb. cleaner, Brake cylinder cleaner and Magnaflux SKC cleaner. This was with head on originally and with head off. Any carbon, gum, etc that might have been causing a ring to stick (and the cylinder/piston/head were surprisingly clean with only a minor bit of carbon buildup. Wish I could get lucky with this one, but it sure seems like the rings are wiped with piston aluminum, will know for sure when I tear it down. I actually ran the motor after reassembling the heads and was not getting #4 to fire at low rpm. On the water, it would kick in at 2500 or so rpm and then the motor seemed lively as ever. Tested compression after running and sameold 90 psi.<br /><br />Ken