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Réglage de l'Allumage du Johnson 70cv
                         [Image externe indisponible : http://www.pccreation.net/dm/photos/20150216180214.JPG]
  Johnson  1978
    Originally Posted by dustycrockett View Post
traxxas, the telltale hose outlet is a nipple on the lower cowl, starboard side.
You can access online schematic diagrams and parts catalogues at http://shop.evinrude.com click on "electronic parts catalogues", select "johnson" in the dropdown box and drill down to your hp/year/model#
Water pump service seems intimidating at first but you can do it:
1. remove prop
2. to disconnect the shift linkage remove the 7/16" hex head screw under the bottom carb accessible from the port side of the engine. I find it's easier to get to if I remove the front of the fuel pump and move it aside. It's held in place with a thumbscrew. There's a screen filter there you need to inspect anyway.
3. remove the trim tab (scribe a mark across the edge so you can get it back like it was).
4. remove the retaining bolt up in the trim tab cavity.
5. remove the other retaining bolt from the bottom side of the antiventilation plate.
6. remove the four retaining bolts from the perimeter, just above the antiventilation plate.
7. pull the lower unit off.
the shift rod height is adjusted by screwing it in or out, so don't twist it or else it won't fit when you put it back.
8. There's a grommet around the driveshaft, don't forget it.
9. Four hex-head screws hold the water pump housing down.
10. Slide the old impeller off the drive shaft.
11. Slide the new one on. Slip the woodruff key in place just before the impeller covers the keyway.
12. Put a new housing gasket in place.
13. Grease the inside of the housing (trailer axle grease is fine), and shove it down onto the impeller while turning the driveshaft clockwise with your hand. Don't use any kind of tool on the driveshaft splines.
14. Fasten the housing back on.
 On reassembly:
* put molly lube on the drive shaft splines (but not on top, there's not enough clearance).
* the rubber o-ring just below the drive shaft splines -- you need that.
* put omc gasket sealant (or some kind of anti-sieze) on the retaining bolts -- or else corrosion will set in & it'll be a bitch next time.
* use 3m #847 or permatex #2 on the joint between midsection & lower unit. www.ishopmarine.com has 847 -- permatex is way harder to clean off there next time around.
I find it's easier to get it back together if I disconnect the shift lever from the cable (starboard side of the powerhead). Just pull the small cotter pin.
Your motor will run best on Champion QL77JC4 spark plugs gapped at .030.
Use only fresh 87 octane gasoline mixed 50:1 with TCW3 certified oil. I add 1 oz. of Seafoam per gallon -- BRP Engine Tuner, Yamaha Ring-Free, or similar. Highly recommended.
Use a "Marine" lower unit gear lube if you can get your hands on it...it will tolerate water a little better than automotive without breaking down.