Re: 1989 Johnson 20HP "Quick help please! =)"
Re: 1989 Johnson 20HP "Quick help please! =)"
Two problems are obvious and mentioned already about the impeller:
1. SOmeone ran the motor without a proper water supply and friction melted part of the impeller. As you've noticed, melted rubber is on the stainless cup.
2. The rubber impeller has "taken a set" and all the blades are set in a curved position, so the impeller can't displace water on idle.
You are probably wise to order the whole kit now since it does appear that the cup is scuffed pretty good. Those things are high, if I remember correctly! it would probably work with just an impeller, but probably not worth trying it.
It appears that one of the previous posters gave you far better advice than I did when he told you to wait to order parts until you've torn it down.:redface:
I hope you left the water tube in position in the midsection, if not you will likely have a hard time getting the tube inserted properly in the upper water tube grommet, and in the lower water tube grommet upon reinstallation of the lower unit. That's one of the slightly tricky parts of the impeller installation is getting the water tube back in the grommet.
Don't worry about the water you saw, that's perfectly normal, water and exhaust drains through there constantly and is the reason for that oddball hole in the side of the lower unit-- so water can drain out of the midsection and not freeze and break the housing.
The grommet you're looking for is called the water tube grommet and you should be able to find the part number on that link to the parts diagram I posted above.
I believe you'll have a nice motor when you get this thing back together!
Go ahead and change your lower unit oil. After you run it the first time, let it sit overnight in the down position like it would be during operation and just barely crack the oil drain plug. If there's any leakage of the seals, a tiny trickle of water will come out since water will sink to the bottom of the gearcase where the plug is located. I suspect there won't be and you'll have a trustworthy engine for many years to come. Don't worry, if a seal is leaking, after a short run that lower unit oil will look like milk when it runs out as well! I don't think there's a better 25hp engine than an '80s OMC.
However, I noticed you were planning on doing some WOT running........I thought you were just going to troll it!
One last thing-----if you don't have muffs to run it on the water hose, make sure your bucket is big enough for the water level to get about 1/2 way up the leg, or about 3 or 4 inches below the exhaust relief on the midsection. Otherwise, you will just ruin your new impeller. Those pumps are not self-priming and the water level has to be over the pump housing or it will not prime. That's a VERY common mistake, one that I've made myself in the past.......
Later,
JBJ
