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1993 Johnson 90h outboard

C

cagba2006

New member
I picked it up for the tilt trim knowing it didn’t run in hopes to fix it, I found one cylinder had 20psi and bad scoring on the walls, I’m thinking it ate a ring I will probably over bore the cylinder and put new piston and rings, just need some torque specs for the whole engine if I’m going to tear it apart thanks to anyone who can help.
 
For a complete overhaul, you might get some well needed information from a repair manual. It's also important to determine what caused the scoring in that particular cylinder.
 
You need 4 new pistons!-----Try WISECO at 0.020" O/S , they come in a kit.-----Putting new rings in an old / used piston is a mistake on those crossflow engines.
 
Ok I picked it up for like $180 bucks only really wanted to put $400 max more into it I can’t just do the one bore and new piston it
 
timguy said:
For a complete overhaul, you might get some well needed information from a repair manual. It's also important to determine what caused the scoring in that particular cylinder.
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Ok what the price on the repair manual and dose it have most torque specs I’ll need
 
I have done my own boring / honing.-----I know that Wiseco pistons are precision made.----You would instruct a shop to bore and finish hone to 3.520"----That is if engine is standard bore of 3.500" now.
 
racerone said:
I have done my own boring / honing.-----I know that Wiseco pistons are precision made.----You would instruct a shop to bore and finish hone to 3.520"----That is if engine is standard bore of 3.500" now.
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Ok thanks for the info anything else I should do while it’s apart
 
Need to determine why the one cylinder failed.----Or motor will fail again.-----I recommend inspection of gears / bearings in lower unit.----Seal kit if all is well there.----Be a shame to spend $$$ on powerhead only to find $$$ gear issues after break in.
 
racerone said:
Need to determine why the one cylinder failed.----Or motor will fail again.-----I recommend inspection of gears / bearings in lower unit.----Seal kit if all is well there.----Be a shame to spend $$$ on powerhead only to find $$$ gear issues after break in.
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Makes sense thanks what kinda pricking should I expect for the bore out
 
Better break open the piggy bank. Make sure trim/tilt okay too. A "Ben" a hole is often what I see. Back in 2007, before our machine shop closed, we charged $75 a pop....nice to have replacement pistons in hand, when possible. When working on a boat....$100 doesn't go far. He!!....a new 90 is 10 grand, brother....you probably know that.
 
timguy said:
Better break open the piggy bank. Make sure trim/tilt okay too. A "Ben" a hole is often what I see. Back in 2007, before our machine shop closed, we charged $75 a pop....nice to have replacement pistons in hand, when possible. When working on a boat....$100 doesn't go far. He!!....a new 90 is 10 grand, brother....you probably know that.
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Yeah just got her for so cheap didn’t know if it was worth putting good money in or just getting a running one and parting it out
 
Depends on your local market as to the availability of good used motors.----Those V-4's " rebuilt " properly are a simple . reliable sweet running machine.----Use better material than some newer 4 strokes !
 
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