Top crank seal on 1983 Johnson 75hp 3 cyl

[gtgeorge]

I have a 75 hp 1983 johnson motor that I bought new, The top cyl is not getting fuel right causing bucking and will not stay on plane. I removed the flywheel and mag and noticed the crank seal has moved up out of the block about 3/8 inch, and there is some oil around it. My question is: Should I use the same seal and drive it back in the block? Or can I get a new seal in there without splitting the cases? <br />Please help!!<br />Thanks much<br />George Sellers

 

[R.Johnson]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

I have run into this only once where the seal has backed out of the bearing carrier. To fix! Lift the old seal out, clean mating surface's with degreaser, apply loc-tite to new seal, drive back in with broad-nose punch, going around seal every 90 degree's until bottemed out. Yes! this would cause a major air leak into top cylinder, and give a lean spit-back.

 

[gtgeorge]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

Thanks for the reply, The seal is not compleatly out just pushed up about 3/8 inch I can see the seating marks on it from where it was. I talked to a local ob mechanic and he said if I removed it the rest of the way I would never get a new one back in there that the cases would have to be split to do the job. He suggested that I jst drive the old one back in. What should I do?<br />George

 

[rodbolt]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

hello<br /> doesnt that seal press into the top bearing? I think it does.<br /> there is no reason to split the case. its not a difficult job<br />good luck and keep posting

 

[gtgeorge]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

rod bolt, I do not know about the bearing, it looks like the seal is just in the cases. Maybe someone on here knows.<br />George

 

[R.Johnson]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

The seal is pressed into the bearing carrier as Rodbolt said, if the seal was completely out you would see the bearing just below it. You could tap the original one back down, but if you do clean it, and put a film of loc-tite around it.

 

[gtgeorge]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

R. Johnson, Thanks for the advice. I will clean around it and loc-tite it, and drive it back in. I need it for a fishing tournament on the Susquehanna river next weekend. This has been a really great motor it has well over average useage. I guided with it for 15 years, and also ran fishery studies for the state, my 4 kids even learned to ski behind it, I put a jet unit on it the day I bought it. This motor is all original except for tune up stuff and carb rebuilds. I have to say I have never had a better motor. But I am thinking about a rebuild. the compression is around 95 lbs on all three cyls. I am thinking about doing it myself. I am a fairly good mechanic with most of the tools I will need. I have been building race cars and motorcycles for the past 35 to 40 years. But have no Outboard experience, but I am not afraid of a challange and I do not want to pay someone else for something I think I can do. so I will need some advice in the future from you all.<br />Thanks<br />George

 

[gtgeorge]

Re: Top crank seal on 1983 Johnson 75hp 3 cyl

Well, I drove the old seal back in, it runs a little better but still bogs at full throttle till I hold the choke in. So I guess I am on the right track. I am going to buy a new seal If I can get the old seal out, I am going to replace it it may be torn or something.<br />George