Johnson rebuild question

[joeycamaro]

1986 90 HP Johnson vro. Runs good, never stalls but it's getting old and I'm considering a rebuild. I'm talking new rings, bearings, carb rebuild...etc. I'd like it running like the day it was born. What's a rough estimate to have it done vs do it myself. I've built Chevy race motors so I'm no stranger to clearances and such, but never a 2 stroke.

 

[gm280]

Okay joeycamaro, I totally understand what you are talking about and equally about 2-cycle engines as well. We all were there at one time. So my best suggestion is to but the Factory, HP, Model, Year Specific Shop Manual first thing. Don't buy one of those after market manuals. They don't cover the engine as the factory manual does. And everything you could possibly ever want to know about your engine will be in that factory shop manual. Even pictures, theory and all specifications. And since you do understand specs, I don't see any problem with you doing the work yourself. I did the same thing with a '76 40HP Johnson myself. You can clink on the link below and see how it came out. :thumb:

 

[interalian]

I just did a full rebuild and converted my '82 90 to a 140 and it runs like a top. 90 was a low-hour unit so all the bearings and crank were still perfect. New 30 thou o/s pistons, rings, carb rebuilds, etc, etc, etc. Farmed out the re-bore to a cycle shop that specializes in boring blind holes and they did a great job. Just back from a week's vaycay on Kootenay Lake and we blasted around there at 45+ (still need to dial my prop in).

Cost me about C$1400 for parts and bore, but I figure if I'd paid a shop to do it, I'd easily be in for twice that. As gm says - buy the shop manual (ePray) and do it yourself.

https://www.youtube.com/watch?v=Kt4AFg92Cc0

 

[James R]

I rebuild these on a regular basis, in fact I have just finished one and I am waiting on a new fuel filter before I run it in the tub. If you want it to run well have all cylinders bored and fit the new pistons. If the cylinders are not bad then 0.010 inch oversize should do it. Wont know until you inspect and measure. Everything will need cleaning and lubricating, crank shaft polishing and the carbs rebuilding. If you have any questions come on back.
The manual is a real good idea.

 

[johnson89]

i did my about 2 years ago...... .20 bore over....about 1300.00 for everything......shop wanted 2500.00