1989 90HP Jonhson Lower Unit Question

[meangreen92]

I started my boat to get it ready for spring...It was not pissing water so I killed it pretty quickly...I checked the hose for dirt dobbers and debri and blew through it...It is clean...I started it again and let it run for about 15 seconds and not water still, not even a trace...

I have ordered an impeller kit and will install on Wends...The lower unit may have other issues...The prop does not turn freely, when I turn it, I can hear it turning, kinda of grinding...It appears the lower unit screw came loose and all the lower unit oil is gone...What should I check for when replacing the impeller to make sure no damage has occurred...

Also, how do I check change the impeller? I have an idea, but some step by step help or a link to video would be helpful as well as any other hints or tricks...

Thanks in advance...
Scott

 

[Johndhii]

Re: 1989 90HP Jonhson Lower Unit Question

Do you own a service manual? Make sure you check the Top Secret Files when you enter the forums, they have alot of information.

http://forums.iboats.com/showthread.php?t=309188

 

[meangreen92]

Re: 1989 90HP Jonhson Lower Unit Question

Thanks for the help...I did the impeller and water pump kit, but when I fired it up it still is not pumping water...Did I do something wrong or do I have another issue...Thanks in advance...

 

[dew2]

Re: 1989 90HP Jonhson Lower Unit Question

How did the old impeller look,Sometimes the water getting to the telltale takes some time,Did you get the water tube aligned and in the lower correctly and in the engine.
My guess is if it wasn't showing water out the telltale before your new install, something is clogged,That is if the old impeller was in OK condition, I dont know how easily the thermostat is removed but it could be removed to see if water is circulating.

 

[Cofe]

Re: 1989 90HP Jonhson Lower Unit Question

If you plan to repair your lower unit, you will need a good manual like this one on ebay. A manual like this cost $75.00 plus shipping on other sites.
http://cgi.ebay.com/ebaymotors/1989...70608359648QQptZMotorsQ5fManualsQ5fLiterature
If you are running your motor in a barrel, the water needs to be above the water pump area on the lower unit. And if your old impeller was shredded, a piece of it could be stuck in the water tube, or the power head. Hope you get it going, the fish are biting

 

[patrick4266]

Re: 1989 90HP Jonhson Lower Unit Question

connect you a garden hose to the water tube, turn it on and see if it is peeing then. If it is nothing is clogged. However, sounds like you got bigger problems. Seems you messed up the lower unit by running it with out oil. Be sure to lets us know how it turns out.

 

[meangreen92]

Re: 1989 90HP Jonhson Lower Unit Question

I have the big service manual and followed the info in the book...Will re-read and see if I missed anything...I actually bought a lower unit a few year back as a back up...Knew a guy that had one in his garage and wanted to get rid of it...Got it cheap...I put that one on with the new impeller...He said it was good when he took it off...I change the oil in it prior to running it...I did put it in gear and the prop turns fine, did not do for long as I heard that can be bad to put it in gear without a load on it...

On the thermostat, I thought they were always open and water should always be running through...Can it close completely and keep any water from running through the block? If so, I will pull it off and check it...I did pull the hose coming up from the lower unit heading to the heads and it did not have any water in it, I would think this is before the tstat, but maybe it has to be open to get a full suction and pull water up?

Anyother ideas? Could I have installed the water pump incorrectly...I will say, the impeller fit in very tightly, is that normal? Also, the kit came with 3 rubber round rubber gaskets, one gasket for under the metal plate and one bigger one to go the housing on top...I only pulled off one rubber gasket down by the plate below the impeller, the one under the metal plate, and the top housing gasket...Could the gaskets be keeping me from getting any flow if I missed one, or would they just slow it down...

Sorry for the rambling, just trying to give as much info as possible so I can try to check it out accordingly...

Thanks again...

 

[meangreen92]

Re: 1989 90HP Jonhson Lower Unit Question

Let me clarify, the rubber gaskets I metioned are O rings, not really gaskets...

 

[patrick4266]

Re: 1989 90HP Jonhson Lower Unit Question

Make sure you have the key in the impeller. Put the impeller on first. Then put a little liquid soap,dish washing liquid on the impeller and housing. Put the shift rod in foward, Push the housing down on the impeller while you are better off a friend turns the prop to the right. Better yet i went and found a you tube vidieo to show you excatly how to do it.

http://www.youtube.com/watch?v=Fj1c4oYpHAw

 

[Silvertip]

Re: 1989 90HP Jonhson Lower Unit Question

Did you install the correct impeller. Did you get the water tube properly mated with the tube in upper section of the motor when you installed the lower unit.

 

[meangreen92]

Re: 1989 90HP Jonhson Lower Unit Question

I assume it was the correct impeller...I call the Iboats number and gave them my model # and that is what they sent me...It looks right, just a really tight fit in the housing, but with the key, it looks to fit right...

It looked like the water tube line up correctly...I watch it go in...Is there anything else I need to do to it when sliding the lower unit up?

I will pull it back off this weekend and make sure the key stayed in and put it back on again making sure all is correct...

Thanks for the info, will do what the vidoe shows as well...

How long should I be able to run the motor with no water without damaging it...Just a safe ballpark...I have not ran over 20 seconds, but read somewhere else that it should not over heat if less than a minute...

Last question for now, could the thermostat be causing No water flow,or does it just adjust to how much? Just wandering if I need to check that still...

 

[patrick4266]

Re: 1989 90HP Jonhson Lower Unit Question

Run it longer than 20 secons to see if your getting water out of your pee hole. Give it a least a minute but not much more.

 

[meangreen92]

Re: 1989 90HP Jonhson Lower Unit Question

I ran it for about a 45 seconds and nothing...Pulled the lower unit again last night and the key was shreaded...Guess I did not get it on correctly...Luckily, they sent to keys with the kit...I put in on, resealed everything, put the lower unit back on fired her up...She started spitting a good stream of water within 3 seconds...I fixed it...Yeah!!!!

Thanks for all the help...Could not have done it without the help...

Good thing is, because I have pulled the lower unit now 3 times, I could this job in about 30 - 45 minutes max now while it took me 3 hours the first time...Got it down to an art...