Johnson 90 hp - water impeller stuck on rusty drive shaft?

[ib18]

Is it blowing water out the exhaust and through the gearcase?

nothing came out of the exhaust which is the back of the motor. It is sipping through the seam between my mid section and the lower unit where the 7 bolts bind the 2 sections together. I will record a video of starting tomorrow after work and report back.

 

[ib18]

I tried taking out the 3 screws in the thermostat housing, and only managed to take out the middle screw. It is impossible to take out the other 2 side screws because no room to back the 2 side screws out without removing the powerhead floor cover. Any suggestions? How can I take out the cover under the powerhead? which number of screws should I remove?

 

[ib18]

Good news - Johnson 90 hp is starting and running today - amazing machine (after all my below average skills changing lower unit oil and impeller replacement).

no alarm from overheating this time

 

[racerone]

????---I agree it is running , after a lot more cranking than is normal for a motor in good condition.-Good luck with it.---Sounds like the starter needs inspection too.

 

[V153]

Were you pushing on the primer when trying to start? Does the primer(s) work?

 

[ib18]

yes, I also suspected that. So, took it to boat ramp and did a real test. It took 4 cranks to start the motor. Water was cool to touch after 20 minutes of running. Took it out into the river for a spin. Water from the peep hole was still cool not warm or hot at all. All is well. Still got 2 issues. One - reverse shift didn't work. Two - Steering wheel cable needs lubrication.

 

[ib18]

Were you pushing on the primer when trying to start? Does the primer(s) work?

no, I didn't. Thanks for the reminder. Everything is so rusty because this is only my 2nd boat season with my Johnson 90 hp Big V4 - it rocks. Last time I used it was working.

 

[ib18]

I tried taking out the 3 screws in the thermostat housing, and only managed to take out the middle screw. It is impossible to take out the other 2 side screws because no room to back the 2 side screws out without removing the powerhead floor cover. Any suggestions? How can I take out the cover under the powerhead? which number of screws should I remove?

#27 screw rusted out, so no way for me to change the thermostats. I simply put it back. I will change them when I get the new thermostats.
I am going to drill out the 2 screws that are holding the lower cover, so I can lower the lower cover to take out the 2 side screws of the thermostats housing.

 

[V153]

I am going to drill out the 2 screws that are holding the lower cover, so I can lower the lower cover to take out the 2 side screws of the thermostats housing.

I see. Hmm. Good luck with that.

 

[ib18]

Nice 2015 first boat ride into the big river again - My Johnson 90 hp (1982) and wellcraft (1974). Very rewarding ride despite my errors and mistakes in changing the lower unit oil and water impeller. This machine is simply tough and reliable. will be ready for cherry blossom.

 

[ib18]

https://www.youtube.com/watch?v=7CmTpmMI9Gc&list=UU5p-k-ES0WCY5ohK1t4TXYw

 

[racerone]

Looks like the boat was originally built for a 25" motor.--It appears the transom has been lowered.

 

[ib18]

Looks like the boat was originally built for a 25" motor.--It appears the transom has been lowered.

Hmm, Don't know anything about that, but the previous owner told me he bought the boat with the Johnson 90 hp V4. He didn't like the heavy Johnson v4 so he replaced it with a mercury 90. He burned the engine after the VRO line ruptured in his last outing. I bought a Johnson 90 hp from a crab fisher man who was using it for crabbing but it cost him $150 gas a day.

 

[ib18]

Now would be a good time to check the shift rod height you never know what someone has done before you got it.
Be prepared for cable rigging adjustments when you're putting it all back together.
Do you have the OMC manual for this motor?

NO

Hi, I didn't know what you were talking about until today I came across this info. Apparently, I should have measured my shift rod to 21 and 23/32". I think this is why my reverse does not work even though my remote control is shifting F-N-R beautifully, but my prop is only doing N and F and no reverse.

Dang, I have to remove my lower unit again to check it - should have asked you what you meant by this.

 

[Fed]

Triple check what the height is supposed to be, this is where a genuine OMC manual for your exact motor comes in handy.

 

[ib18]

can somebody share the proper shift rod length for my 1982 Johnson 90 hp V4 so I don't have to buy the manual because I know many of you probably have the same outboard I have? J90MLCNB is the model of my outboard.

My lower unit is dropped this am, so I am waiting for your response to put it back.

The prop seal is definitely broken so it is leaking oil big time.

 

[Fed]

I found 2 sources that agree with both yours & also my 1988 model.

 

[ib18]

Wow, thanks a million. I tried 21 23/32" before I saw your post. Sure enough it didn't work and came out too short. I dropped the lower units 4 times by trial and error and ran out of time - family duty called and had to quit. I will drop it again and measure it to 21.84" in neutral. No wonder it was too short for me to trying linking it to my shift linkage. I will drop it again in a few weeks when shad and stripe bass fishing is slowing down to seal the lower unit completely and change the thermostats by drilling out 4 rusty bolts to remove the lower cowling.
I took out the lower unit because a few days ago when I tested my Johnson 90 at the boat ramp for water temperature from the pee hole. I noticed I didn't have reverse. I thought the lower unit gear was bad. I checked the lower unit after I dropped it. I pressed the shift rod down and pulled it up to shift between R-N-F. Thanks God, everything was still good for the lower unit. I believe this correct shift rod measure is going to solve my no reverse problem. Will keep you updated tomorrow.

Hats off to you Fed.

 

[Fed]

Depends on your measuring stick but I'd be using either 21&27/32" or 55.48cm as I've never seen a tape graduated in Metric Inches such as 21.84".
I guess someone makes them but I doubt you would have one.

 

[ib18]

I took my boat to the boat ramp and tested the F-N-R. everything works beautifully - https://www.youtube.com/watch?v=XG39YQo1ARc But, my motor would not shut off even after I pulled the key from the key switch.
BTW, I don't have a kill switch because it was cut off.
What could be the reason?