1984 50hp Evinrude Overheating

[whatever_emily]

So I recently bought a boat with this engine (1984 50hp evinrude e50belcrm), and I can not seem to get it to pee. First thing I did was run some weed trimmer line up the pee hole to look for obstructions, I blew compressed air through the pee hole, I removed the lower unit and replaced impeller even though the old one looked fine. I put it all back together hoping it would work and nada. I even took it to the lake and ran it till it got very hot to make sure there wasn't something wrong with my bucket or ear muffs. I then took the lower unit back off and blew air through the pee hole again and confirmed that it was exiting the copper tube and I blew it through the cooper tube and confirmed it was coming out the pee hole. Then I took the water pump apart again there was water on the impeller from the lake so I know water is getting to the impeller. Here is where I am stumped...I tried hooking a hose to the copper pipe to see if water would come out pee hole and nothing did. I didn't turn the hose up really high because I have read that you can cause problems by doing this. But if I put water to the pee hole it come out the copper pipe immediately. Also the copper pipe has a small hole in it about 2 inches from the bottom. Is this normal? I didn't really want to have to take off the head to get to the thermostat because I have read horror stories of broken bolts. Anyways any help would be appreciated. Thanks

 

[oldboat1]

The worrisome issue is that the motor got very hot. 160F or over is an overheating situation (too hot to touch for most folks), 120-140 is normal. Depends on conditions. When you ran water up the water tube, did it exit down the leg (i.e., out the exhaust).

Check the water intake at the lower unit for blockages (sand, weeds, etc.)

You may need to remove the head to access the water passages around the cylinders -- any obstructions will need to be cleared (hacksaw blade works pretty well for this, used with care). Much as you hate to get into it, the problem may be a t.stat or debris in the t.stat cavity (blocked bypass).

It wouldn't hurt to grab a flashlight and look up at the powerhead when the l.u. is removed. Look for critters nests.

 

[whatever_emily]

There was a slight dribble that came down the leg. The rest was spraying from that little hole I was talking about on the copper pipe, and then when I removed the hose a bunch of water came back out the copper tube.
With the lower unit off I have looked up towards the powerhead with a flashlight but didn't notice anything that looked weird. That being said I didn't really know what to look for. Thanks

 

[oldboat1]

If I understood correctly, it sounds like the water tube (inlet) is blocked at the powerhead (exhaust housing adaptor). This is not unheard of, as the grommet gets contorted and blocks water flow.

It may be possible to remove the water tube from the bottom, so wait for suggestions on that. I believe the fix is to remove the powerhead and expose the adaptor, however -- fair amount of work with the larger motors, but still DIY.

 

[whatever_emily]

Even with the air going through you think its still blocked? Maybe just a partial blockage and the air has more pressure behind it so it makes it through but the water won't?? Thanks

 

[oldboat1]

Don't know exactly how you have a hose attached, but sounds like water pressure hasn't pushed out the blockage yet. Water subsequently runs back out the inlet point. Air isn't real useful for leak or blockage diagnosis -- maybe cigar smoke.

 

[whatever_emily]

My hose attaching method was definitely less than ideal. Picture MacGyver with duct tape.

 

[oldboat1]

been there, done that. For future reference -- One of those quick disconnects (male end) helps to step down the diameters. But probably still need the duct tape.

 

[racerone]

Overheated?----Do a compression test first.

 

[whatever_emily]

Ok I'm back to the drawing board. The whole air getting through and water not was getting to me so I went back out and found a better water connection and water does make it out the pee hole just fine. So now my problem lies below the water pipe...I think? I have replaced the impeller but something must be missing. I'll do more digging and then give you an update. Thanks

 

[oldboat1]

....But don't fire it up until the water issue is solved. For compression test, remove plugs. Hook up the tester, and crank until the needle stops moving (five to ten seconds, maybe). Record the finding and move to the other cylinder.

Check the water intake in the lower unit -- mud, seaweed, etc.

 

[oldboat1]

If the intake is OK, think you need to revisit the water pump work. The key for the impeller may have been dislodged, or perhaps the water tube was not inserted in the grommet down there (or the grommet is faulty).

 

[whatever_emily]

I know the key was in the correct spot. I feel like the water tube was inserted into the grommet because i couldn't get the lower unit up at first because it wasn't lined up correctly. Once I got it lined up it slid in nicely. The grommet could be faulty I guess. It looks old. Thanks

 

[oldboat1]

You have determined that the water pipe is not blocked. If water was gushing down from the powerhead area, you also know that water is going through the powerhead. So it would appear you have to determine why the water pump is not moving water to and through the powerhead. That is the job of the water pump, using open water intakes in the lower unit.

I would take off the gearcase again and check the water pump. With the l.u. removed, you can turn the driveshaft clockwise by hand and feel resistance from the impeller -- provided the impeller is moving with the driveshaft (key has not been dislodged). If the impeller is moving with the driveshaft and the water intakes are clear, the pump will push water up to the powerhead.

If you remove the l.u. and put it in water deep enough to cover the impeller, turning the shaft by hand will move water up to the water pipe grommet, where it will run out -- if everything is working correctly.

 

[whatever_emily]

Thanks for all your help oldboat1. After taking off the lower unit (again) and inspecting the water pump again I figured out that water pump key that I bought was too small so it would catch a little, but when put any real resistance on it it would slip and the water pump would stop spinning. Yea problem solved I made a new key and now it pumps water like it should. Ok so here is my next ridiculous question. I had to make a key that would fit onto the shaft and the impeller. I know it works since I have tested it. Would I be foolish to keep this one on or should I go and buy another one and hope that it works better? Thanks

 

[oldboat1]

Well, water pump function is probably as important as anything else, or more so.

The oem impeller for your motor is 777129. The key is 323950, shown here: http://www.marineengine.com/newparts/part_details.php?pnum=OMC0323950 The key is kind of an odd duck, and I'm not sure what you came up with.

Guess I would suggest and oem impeller and key to be safest, although that probably is not what you would prefer to do. One option would be to install the oem impeller and key, and keep what you currently have for back up(?)

(don't want to tell you something that might leave you in the middle of the lake with a torched motor on the transom!)

 

[racerone]

You can get into issues when lower units from different years are installed.--------Some used a woodruff key.----Some a round stainless pin.----And some used a plastic " wedge " key.-----Helps to know what is there and what years fit what.