Johnson 4 HP impeller

[tom-c]

Got this ’85 Johnson 4 HP back together today. Started on the third pull and it pumped water for about 3 minutes. This motor has a neutral/forward shift. Do I need to pull the power head to replace the impeller? How is the shift linkage connected?

[dougs-outboards]

If this is it, looks like 2 bolts at the bottom of the gearcase and it pulls right out.

You can get an impeller on this page too.

http://www.marineengine.com/parts/johns … n=Gearcase

[tom-c]

Gotta be more than that. There’s a gearshift handle at the base of the powerhead. I removed the two gearcase screws and it won’t drop down. So I loosened the five powerhead screws and that won’t separate either. That shifter needs to be disconnected but I can’t figure out how.

[PugetSoundBoater]

What is the Model Number?

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[billw]

It does pull right off with the removal of two bolts. The shift rod just goes into a sealed hole and either touches the neutral spring or not, to engage or disengage. It does not actually connect to anything and will pull right out.

Long live American manufacturing!

[tom-c]

Ok. Will try it again. Must be stuck and I was afraid to force it. Thx.

[retiredoz]

Sounds like we have the driveshaft/crankshaft weld going on..

[tom-c]

I managed to get the powerhead off with a lot of force and it pulled the driveshaft out with it. Pulled it right out of the water pump. The gearcase is now off but now I have to figure out how to get that driveshaft out of the crankshaft!

[dougs-outboards]

Powerhead upside down, soak driveshaft/crankshaft union with penetrant for awhile. Gently tap on end of driveshaft to shock loose.

Impeller pin might have broken the impeller housing on it’s way out the top, might need another housing. I might have one if memory serves correctly, would send it to you for shipping costs. Let me know ok?

Good luck!

[fleetwin]

If Doug’s method does not work, please do not grab the lower portion of the driveshaft with vice grips or anything else that will damage the sealing/bearing surfaces of the lower driveshaft…
Removing the powerhead is easy and will give plenty of access to the driveshaft without worrying about damaging sealing/bearing surfaces…
Once the driveshaft is out, be sure to clean up the splines well. Next, tip the powerhead upside down so its splines can be filled with light penetrating oil such as WD40. Now, work the driveshaft in and out of the crankshaft many times to remove as must rust as possible…
Yeah, the plastic pump hsg was probably wrecked when the driveshaft key pulled through it…Use a complete water pump kit…
Reinstalling the gearcase is a challenge for sure. Using your fingers to blindly guide that shift rod back down through the gearcase opening requires some luck indeed….Either they just pop into the gearcase no problem, or you will spend plenty of time, using creative language, to coax the driveshaft back through the elusive shift rod hole….

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