9.9 johnson rebuild.

[rolmops]

I am currently rebuilding a 1975 Johnson 9.9 hp.<br />While searching for replacement pistons I found a conflict between different manuals.Where Seloc implies that the pistons are the same from 1974 and on,other books claim that a change was made in 1981,appearently with the thickness of the wristpins and from roller pins in a housing to roller pins without a housing.The pistons are still cross flow.<br />Can someboby please enlighten me on what is going on and whether I can use post 1981 pistons in a 1975 engine?<br />Thank you for your help.

 

[Paul Moir]

Re: 9.9 johnson rebuild.

I have no direct experience with that engine, so perhaps someone else can comment on the interchangability. Probably something different about wrist pin hieght.<br /><br />The OMC parts book indicates that the '81-'92 piston is different from the '74-'80 one. But that the wrist pin & piston rings are the same.<br /><br />9.9hp '74-80 piston<br />STD: 391526, +.030" 396573<br />Rings '74-92<br />STD: 386279, +.030" 386280<br /><br />EDIT: Oh hang on, it seems like you need the post '81 wrist pin with the new pre '81 pistons...<br />EDIT (Again): Ah, it seems Dhadley has the answer!

 

[Dhadley]

Re: 9.9 johnson rebuild.

Sure, no problem. If you use the 81-92 piston you need the W5215 wrist pin kit from Wiseco. With that kit you can use their 3136 piston in either style motor or the OE piston from 81-92.

 

[MCM]

Re: 9.9 johnson rebuild.

Sounds like great info. Just thought I'd add this link in case you hadn't seen it, there's some pretty good info in there concerning your motor.<br /><br /> http://www.wisnersinc.com/Fishing Info/Johnson 9.9_15.htm

 

[rolmops]

Re: 9.9 johnson rebuild.

Thank you guys for the info'<br />I'll order the wiseco set tomorrow and hopefully,weather permitting,she will run again in another 2 or 3 days.

 

[Dhadley]

Re: 9.9 johnson rebuild.

Cool! Let us know how you make out. <br /><br />If you need help getting the kit let me know. I assume you'll order thru WSM or Pro or someone like that.

 

[rolmops]

Re: 9.9 johnson rebuild.

Hello Dhadley.<br />Your advice was right on.I did get the kit and put her back together.I tried her in a barrel with a water-antifreeze mix and she purrs like a kitten.<br />Got to wait for the waters here to become liquid again then I'll try her on the lake.<br />Thanks again.

 

[Dhadley]

Re: 9.9 johnson rebuild.

Thats great. Thanks for the update! I think everybodys ready for spring....