1984 Johnson 115 Water Pump question?

[reb0707]

Hi All, Yesterday morning I started the motor on the trailer w/o turning on the water. Ya dumb I know. I ran it for 30 seconds to a minute before realizing. I have been told their is like a plastic wheel that touches metal that forces the water through the engine. I took the boat out for a few hours yesterday and had a steady flow of water pissing out the motor. Someone told me I should replace the wheel anyway. What do you guys think? Also I herd it is quite difficult to do.

[AEROCOOK]

I'ts not hard to do and YES it needs to be done! Dont run it till you replace the pump. Damage to the water pump impellor from running out of water can occur in 5 seconds let alone 30 to 60 seconds.

[levi_tsk]

the impeller is rubber and the cup inside the housing is metal the impeller rides inside the cup and is turned by the driveshaft for the engine any dry running wears the impeller alot so yes time to drop the lower unit and replace the impeller - clean the cup with scotchbrite untill its shiny make sure it will still slide out of the housing while your cleaning it - if it wont the housing is shot too

[emdsapmgr]

In your case, the rubber impeller may have gotten hot enough to laminate the stainless steel cup (liner) with a black, hard substance. If this is the case, you will have to replace that cup in addition to the impeller. It may have gotten the plastic housing hot enough to deform it also.

[emoney]

It's not hard to do and yes, it needs to be done. It doesn't take but just a tiny bit of the wrong kind of luck for impellers to fail. By forcing your luck, you've narrowed it down. They really should be changed every couple of years on freshwater motors and annually on salt water motors regardless, so you would probably be doing it anyway. Anyone that tells you, "you'll probably be all right..." or anything similar is probably following you around with a camera waiting for the failure to occur.

Read and the read some more right here on this forum, post up a lot of pictures, and we'll get you through it. The "sticky" at the top of this forum title 'Top Secret Files' has links to threads containing detailed information, including pics, of exactly what you're about to do.

[reb0707]

Ok Guys, I followed your advice and took the boat to a different mechanic who specificly works on Johnson and Evenrudes. This motor is only used on salt water. Also the motor has a 1984 power head on it. I am going to try and repeat what he told me. He said he was unable to take off the lower end. He said someone may have forgotten to put an O Ring on the shaft last time it was taken apart. He said the repairs may be extensive and the motor may not be worth it. This Sucks. He asked if I used the boat after I ran the motor? I said yes I used it for about 2 hours of run time. He asked if it overheated? I said no it ran perfect. I have a water temp gague and the factory alarm on the boat. He said I should be fine and run it until I have problems. This does not make me feel very good. I was planing on taking the boat off shore fishing this weekend. What do you guys think?

[levi_tsk]

have you got tow boat u.s.?? if not you need to figure out how to get that thing apart....

[boobie]

Whats that old saying? "Living on borrowed time".

[reb0707]

Ya I got tow boat us. The thing that's making me happy is the fact that I am underpowered. I have a serious transum on the boat. Again it's a 19.2' Key West. I think I will be safe going up to 175 HP. I just need to save some money. This boat was way underpowered w/ this 115. I am still going off shore 10 mi on Saturday. I have my cell and radio if I get in trouble. One of my friends went out today and got 9 dolphin and 1 Tuna. I want some too. Thank all of you

[kenmyfam]

Ok Guys, I followed your advice and took the boat to a different mechanic who specificly works on Johnson and Evenrudes. This motor is only used on salt water. Also the motor has a 1984 power head on it. I am going to try and repeat what he told me. He said he was unable to take off the lower end. He said someone may have forgotten to put an O Ring on the shaft last time it was taken apart. He said the repairs may be extensive and the motor may not be worth it. This Sucks. He asked if I used the boat after I ran the motor? I said yes I used it for about 2 hours of run time. He asked if it overheated? I said no it ran perfect. I have a water temp gague and the factory alarm on the boat. He said I should be fine and run it until I have problems. This does not make me feel very good. I was planing on taking the boat off shore fishing this weekend. What do you guys think?

You need a new mechanic and to change out the impeller. Check this link out for details. The lower unit WILL come off. It just needs time and gentle encouragement.

http://forums.iboats.com/engine-frequently-asked-questions-faq/1985-johnson-water-pump-job-photos-lots-309188.html

[reb0707]

Thank You kenmyfma, Unfortunately this link did not address my issue. That is, from what my mechanic told me, and the owner of another business who does work on boat motors is that the stainless steel drive shaft is rusted into the motor. They suggested to remove it you need to cut threw the exhaust and heat the bottom of the motor. They said the drive shaft would most likely have to be replaced. Of course I am not going to go this rout. I would like to find out if their is a way to separate the shaft from the motor with out having to go to these extraordinary measures.

[Daviet]

OK, this is an extreme solution, but it has worked for me when I was working on salt water engines. You can loosen all the bolts that hold the power head down, start the engine on muffs and let it run. Sometimes the vibrarion, or lack of alignment between the driveshaft and the crankshaft will break the corrosion loose. Like I said it's extreme, but has worked.

[reb0707]

Great idea! right now the motor is pissing fine. My mechanic said I should just run it for now. I am thinking when we get closer to winter I will mess with it. I definately like the vibration theory.