Johnson 70hp head gasket replacement and powerhead removal to fix water in the cylinders

[@DC_888]

Hey mate, going through a similar exercise on an Evinrude 70HP of the same vintage. No water in the cylinder but some gaskets weeping. Did the head gasket which wasn't weeping but in far worse shape than yours so needed replacement anyway. I do have a weep from the exhaust cover gaskets. I suspect I'll have some broken bolts like you did when I disassemble. Where did you get bolt replacements? Anywhere local? Funnily enough I'm also based in Perth!

[@ExperimentalHV]

Hey, hopefully your exhaust assembly comes apart better than ours. I would suggest trying L&T Venables in Wangara or Malaga, they have all sorts of fasteners etc. I disassembled this engine completely and the salt water had been inside the crank case which damaged the bearings etc So we weighed out the cost and time… ended up finding a good deal on a 2003 115hp Johnson, had to do a fuel pump on that engine but it goes hard now.

[@DC_888]

@@ExperimentalHV thanks mate really appreciate the response.

[@sheckb1]

Hey bud, great video. Have one of these old rudes myself, looking to get it back on the water. But I was wondering, how deep is the water jacket at the top of the head? Looking to add a telltale to mine but trying to work out where to put it. Cheers.

[@ExperimentalHV]

I can’t recall unfortunately, there is a chap who’s put one on a later model, that may be of some help. Hopefully you can get her back up and running. kzbin.info/www/bejne/q2O7e3icqKijb7M

[@LoganRowley-s8n]

Hey guys great video just wondering with removing the powerhead how did you lift it off did you need an engine crane or anyrhing like that or is it pretty light? Thankd you

[@ExperimentalHV]

Cheers, highly recommend an engine crane, with the two of us we man handled it off. Wasn’t the easiest from memory.

[@mikegonzo721]

Im having the exact issue with my 70. Started with the head gasket. Same result. Did your exhaust work fix the issue? What did you mean by the last comment in the video?

[@ExperimentalHV]

I ended up tearing the engine down further and discovered water had made its way into the crankcase as well. The salt water must have seeped past the rings and didn’t do anything favours. My mate and I decided to unfortunately cut our losses and bought a 2003 Johnson 115hp for 3K Aud. The VRO ended up being faulty on that causing over oiling, replaced the VRO and the boat flys now.

[@mikegonzo721]

I don't have any salt deposits in this motor. I think I'll try the exhaust gaskets and adapter plate gasket and hope for the best. So do you think your block was cracked?

[@ExperimentalHV]

@@mikegonzo721 best of luck, fingers crossed your bolts aren’t as bad as ours were. Nah no crack in the block, water seeped in through the exhaust port and into the cylinder. Then made it’s way past the rings and made friends with all the bearings etc

[@mikegonzo721]

Just pulled the power head. No issues. No seized bolts. Not sure if water seeps into the crank. Signs of leaks were clear in the exhaust as well as the head. I'll run it! It's my last resort! I'll let you know what happens. Thank you for replying so quickly!

[@ExperimentalHV]

@@mikegonzo721 no problem Mike, best of luck and hope you can get it sorted🤞

[@ce3810]

Were the reeds bad?

[@ExperimentalHV]

Reeds were ok, it seems water was getting in from the dreaded exhaust housing