Used powerhead switchout on Johnson 70

[Gleaner]

Johnson 70 seized a piston as I posted about before. We found a used Evinrude 70 E70ELCIM. The Johnson is J70ELCD. Evinrude is a 1981 and the Johnson is a 1986 vro. Compression is great in the Evinrude, so we are wanting to put the Evinrude block in the Johnson frame. Can we put all the Johnson electronics and carbs on the older Evinrude powerhead? We are not going to hook up the Vro again, but wanted to use the newer motor parts as much as possible. Would have been simple to just use the complete older Evinrude, but that motor has been in saltwater and in the elements, so the Johnson appearance is much better. Thanks

 

[Gleaner]

Re: Used powerhead switchout on Johnson 70

^

 

[Dhadley]

Re: Used powerhead switchout on Johnson 70

They are different motors. The 81 is a 49 CID and the 86 70HP is a 56 CID and although the mounting bolt patterns are the same the exhaust is in a diffetent location (different base gaskets).<br /><br />Why not just fix your 86? Most likely it just scuffed the middle cylinder. We know what causes that.<br /><br />Good luck!

 

[Gleaner]

Re: Used powerhead switchout on Johnson 70

DHadley, <br />thanks for the reply. The bottom piston has big chunks out of it, going into the ports. I just thought I could switch blocks faster and cheaper as I will have to bore the 86 and put in a new piston. We really don't know much about tearing down the motor. If the 1981 won't fit We won't have any choice.<br />Thanks,<br />Dan

 

[Dhadley]

Re: Used powerhead switchout on Johnson 70

What fuel and plugs were you using?<br /><br />Good luck!

 

[Gleaner]

Re: Used powerhead switchout on Johnson 70

This motor is actually a friends that I am helping to get back together, although I was in the boat when the motor pulled down and seized, only 500 yards from the ramp. After reading on this site I asked him if he was using good oil and fuel. He buys OMC oil and the plugs are champion L77JC4. It was very hard starting the last couple times I was in the boat, so i suspect (again from readings posts), that he has never used seafoam or other carbon cleaners, and maybe #3 was the first rings to stick. We are learning a great deal from this site on engine maintanence.

 

[Gleaner]

Re: Used powerhead switchout on Johnson 70

DHadley,<br />between the "middle unit" and the powerhead there is another section of outboard that the exhuast port is in and the gasket glues to. Will this piece switch out between the 2 motors? If so, I can still use the old powerhead in the new cowlings. Also, will the electronics pak just bolt on from the 86 to the 81 powerhead? Or would you stay with the exisisting electroics?<br />Thanks,<br />Dan