Couple of questions from an Old Salt

[USN72]

What would the correct spark plug be for the 1975 Johnson 70 horse outboard. Also behind the propeller on the shaft there is a metal cased oil seal. Any tips on how to R&R it? Looking forward to your reply.

 

[HighTrim]

Re: Couple of questions from an Old Salt

Champion QL77JC4 gapped to .030

I suppose you do not have a manual?

 

[USN72]

Re: Couple of questions from an Old Salt

No manual came with the motor however I did find the exloded view of the lower case only problem with that is it just shows the break down of the unit.

 

[Lou Eppell]

Re: Couple of questions from an Old Salt

That engine does use Champion QL77JC4 plugs but it is recommended that the gap be set to .040.

Other than removing the carrier assembly and removing the seals properly, if you are carefull not to scratch the propshaft, you can use a long skinny thin screwdriver and wedge the blade between the seal and the propshaft to pry them out. There are two, the inside one facing in with the outer one facing out. This method is a last resort type thing.

 

[USN72]

Re: Couple of questions from an Old Salt

Thank you for the advise, I will give it a shot in the AM.

 

[R.Johnson]

Re: Couple of questions from an Old Salt

Don't try prying those seal's out with a screw driver with the unit it place. You are trying to avoid a leak, not create one.

 

[kynolan2183]

Re: Couple of questions from an Old Salt

The recomended gap is .30, there was a tech notice in the 80's.
I use NGK plugs and have smoother Idle than with the Champs.
It took some time to find the correct NGK plug that worked great in winter and summer.

I found the Champs were hard to start when the temp was below 30 F.


Kyle

 

[flabum]

Re: Couple of questions from an Old Salt

For those seals. There are three bolts down inside the bearing carrirer that use a 5/16" socket to remove. remove those bolts. Remove the carrier, This may be difficult if it is a saltwater motor, some heat will be necessary. Once the carrier is out, you can easily replace the seals and o-rings. You will need a long piece of 1/4"-20 threaded rod to use as a guide for the plate in the gearcase and carriereras you assemble it.


Good luck.