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  #1  
Old 02-01-2010, 11:11 AM
BRUCE CARLSON BRUCE CARLSON is offline
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Default 1993 Johnson 120

My "new" used boat has a 1993 Johnson 120 hp. I thought this year/model was labeled "Fast Strike". Did Johnson produce 2 different 120 hp 2-stroke motors in 1993?
Anyone with knowledge/experience with this motor....your info is welcomed.
Is there anything I should be checking?...water pump, oil injection, ect.
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  #2  
Old 02-01-2010, 02:35 PM
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yarcraft91 yarcraft91 is online now
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Dunno about the Faststrike label.

I have a 1991 120 Johnson. Last year, I was having some running problems, poor starting, too-fast and unsteady idle speed, stalling in gear, all indicating a lean-running condition. So I did the following:
- Replaced spark plug wires.
- Changed spark plugs from QL77JC4 to QL78YC (dealer-recommended update).
- Torqued the carburetor and manifold bolts (several were loose).
- Removed black pulse dampener driving the fuel pump, replaced with blue pulse dampener (blue dampener is a factory-recommended update, part numbers appear to be the same)
- Checked/adjusted the timing (was 4 degrees over-advanced). Funny story here...
- Re-torqued the head bolts (none loose).
- Replaced the entire fuel hose (needed!). Found and replaced 2 broken fuel hose clamps! Check every one of them!
- Checked head temperatures (all fine).
- Decarboned with Seafoam.

Runs just fine now! Can't think of anything I did that isn't a good maintenance item at this motor age. I've owned it since new and it's been a great outboard!

On the spark plugs, the QL78YC is a bit hotter than the standard factory plug, which helps because I rarely run the motor at WOT, usually cruising at 3000-4000 rpm. I've had the same recommendation from others familiar with this motor. Another recommendation was to use the QL82YC, which would be hotter yet- I'm told that was the standard plug in older versions of my motor.

Last edited by yarcraft91; 02-01-2010 at 02:55 PM. Reason: Added info on QL82YC plugs
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  #3  
Old 02-02-2010, 04:49 PM
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T Mac T Mac is online now
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Quote:
Originally Posted by BRUCE CARLSON View Post
My "new" used boat has a 1993 Johnson 120 hp. I thought this year/model was labeled "Fast Strike". Did Johnson produce 2 different 120 hp 2-stroke motors in 1993?
Anyone with knowledge/experience with this motor....your info is welcomed.
Is there anything I should be checking?...water pump, oil injection, ect.
As I recall... in '93 they produced a 120 and a "118 Special" which was non oil injected.
In '94 (or '95?) they produced 2 115s. The old 90 degree V style and the new FastStrike (60 degree V).
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Old 02-02-2010, 05:33 PM
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yarcraft91 yarcraft91 is online now
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Another thought on that 120. On my 1991 model, the water stream from the indicator hole is not very strong- doesn't shoot out like the newer Mercs, just sorta runs out in a stream about as big around as my little finger. It's been like that since new and a replacement water pump didn't change that, so apparently it's characteristic of the motor.

Easy motor to winterize- get an aerosol can of fogging oil or Seafoam Deep Creep with an adapter (built into some Johnson/Evinrude product cans) to connect to the Schrade valve on the fuel line just under the fuel pump. Push the dispense button for 20 seconds while the motor is running at idle and fogging is done! But, whatever you do, don't change the position of the valve handle!! That will flood your engine with oil.
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Old 02-03-2010, 09:26 AM
BRUCE CARLSON BRUCE CARLSON is offline
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Default Good to know!

Thanks for the great info!


quote=yarcraft91;1165484]Another thought on that 120. On my 1991 model, the water stream from the indicator hole is not very strong- doesn't shoot out like the newer Mercs, just sorta runs out in a stream about as big around as my little finger. It's been like that since new and a replacement water pump didn't change that, so apparently it's characteristic of the motor.

Easy motor to winterize- get an aerosol can of fogging oil or Seafoam Deep Creep with an adapter (built into some Johnson/Evinrude product cans) to connect to the Schrade valve on the fuel line just under the fuel pump. Push the dispense button for 20 seconds while the motor is running at idle and fogging is done! But, whatever you do, don't change the position of the valve handle!! That will flood your engine with oil.[/quote]
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  #6  
Old 02-03-2010, 03:57 PM
staylor staylor is offline
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Default 120 HP= good motor

If I recall, they built both a 115 crossflow and the 120 looper in 1993. I remember the Fast Strike marketing label which was used on the larger engine also- and may have been a way of identifying the loop charged motors. Both the 115 and 120 hp motors were good runners with very little trouble. The only issues I recall was a slight carb jetting problem with the idles on the 120s- when you stopped a warm engine and let it sit for about 20 minutes the re-start sometimes would be a bit slow, and you had to let the motor idle for about 30 seconds before throwing it into gear or it would stall. The VROs would start to leak a little bit now and then and usually you could fix this by just tightening the screws near the leak point. My son has a '93 120 that he bought used from a relative who was never too kind to his motors. He's had it 2 seasons now with zero issues. There are several different spark plugs that at one time or another seemed to be "the best" for this engine, but all seemed to run pretty well. Don't be surprised if the plugs in the motor are different than what the dealer shows as current- and you may end up liking the old plug type better than the new one.
Doug
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