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'74 V4 lower unit question

R

rsdata

New member
I have posted before about this engine. I got it starting and running pretty good and used it twice on Lake Erie for a couple of good long runs. The 15 year+ old water pump impeller did a good enough job in 52 degree water to keep the engine cool. However I do want to drop the lower unit to replace the impeller AND to seal the lower unit from leaking gear oil. The gasket that seals the lower unit from the engine leaks gear grease and I suspect lets in water in three separate places. Yes... the lower unit did get water in the housing. I drained about 1/4 cup each time I pulled the boat from the water. I am looking for help in how to drop the lower unit. I did this only once about 20 years ago on an '89 Johnson 40. I think I have to RELEASE the shifting linkage from somewhere near the engine, then unbolt 4 bolts that hold the lower unit on. 1) Where or how do I disconnect the shift linkage? The motor has a faded sticker on it that says Powershift on the engine cover. Is this something to consider? 2) When I drop the lower unit I will inspect the seals and gaskets and impeller housing to see what needs to be replaced. Any suggestions for proper maintanence? thanks again in advance for your help Roger
 
You will need to remove more than 4 bolts, check your manual.----Powershift is not a factor in dropping the lower unit.-----A 5/8" wrench is needed near the carburetor ( starboard side ) to disconnect shift rod.
 
Thanks racerone I don't have a manual... I found 5 bolts...
could there be any more??? I have not dropped the lower yet, but I did take off the carbs to access the 5/8 bolt and shift rod which was directly beneath the bottom carb... I started to take off the cowling, but two bolts were impossible for me to get to below the lowest cylinder... that is when I realized that I could get at the shift rod below the lower carb... going to wait until morning to try and drop the lower unit and inspect what needs to be fixed/replaced...
Using the manual online here for '74 115 HP, they reference 3 different models.
This engine has no model or serial number tag on it. Are there significant differences between the three different models referenced here online? These are
the three... which is the most likely that I have?


 
http://www.brp.com/
Only the first one in your list is listed on the above website for Evinrude.
The other two are Johnsons. Is yours a Evinrude or Johnson?
In the 73' Evinrude catalog power tilt and trim combo, or power tilt only were options.
I don't think it matters much in dropping the lower.

There may be six bolts. Did you get the one under the trim tab?
99, 97, and four 95s.
 
thx jm18611865... I have checked under the trim tab and there is no bolt there. I removed two bolts from each side and one from just ahead of the trip tab. This is an old Johnson 115 that racerone ID'd as a '74 from pictures that I posted here... http://www.marineengine.com/boat-fo...nson-taking-out-of-storage-and-need-some-help The engine has no ID tag on it. I have owned it about 15 years, used it for 5 years, then stored it for the last 10. It is a trim/tilt model but those parts are long gone. I now have the engine mounted on a trim/tilt replacement bracket that sets the engine back off the boat by about 6 inches which is great. I got the engine running fine, but after running it on Lake Erie on two different days last week, I find that I have lower unit leaks. Two leaks are from the mating surface of the lower unit with the engine, and another that looks like it might be a corrosion hole just below the mating surface. I have taken off the 5 bolts that hold the lower, and detached the shift rod from below the carb. I am having trouble removing the lower unit now. I have about 1/4 inch gap by the prop end of the lower, but only maybe a 1/16 gap at the front. The lower will not drop off. I have hit it with a hammer and wood block, and tried to use the trim/tilt control with a length of wood to lower the engine and press on the front of the lower unit down by the prop. I have been squirting PB Blaster (Liquid Wrench) into the gap and have been trying to take this off now for about 24 hours (on and off, trying not to force anything). I think significant corrosion inside the housing or on the drive shaft or the shift rod is holding me up. I am trying not to pry to hard on the soft metal of the lower unit so I don't bugger up the mating surface. I have turned the engine over a couple of times thinking maybe the spline shaft might be holding me up also. Does anyone know of anything that I can do to hasten this lower removal, or do I just have to keep pounding on it (using wood block and a heavy hammer) and wiggling it until it finally gives way? Any advise would be appreciated. I know I should just dump this engine and get something newer, but at this point it is almost a challenge to see what is going on inside the lower unit and try to fix it up.
 
UPDATE Re: '74 Johnson V4 lower unit question

rsdata said:
I am having trouble removing the lower unit now. The lower will not drop off.
Click to expand...
UPDATE Kept up hitting, prying, turn engine over, and finally the LU popped free. Corrosion does not seem to be the issue, probably just a dry spline shaft. I will be sure to put a little grease on the splines when I reassemble. There were two small holes just below the mating surface, one on each side, that I now see were nothing more than weep holes machined into the LU. I had some LU 90wt/water emulsion dripping from these weep holes and a couple of spots where the LU attaches. I thought that the LU mating surface was gasketed, but now I don't think so... is there a gasket? In the LU water pump area, I found insect wings, and 2 whole insects (looked like wasps) in the cavity that holds the water pump. Amazing how these insects get into places they should not be. NOW... to restate my problem... I did have water in the lower unit each time after running the engine, less than a 1/4 cup. Can someone help with the parts that I need to order to seal the LU from getting water in? Is it likely the water is coming in through the prop shaft? Or is there a way that water seeps down into the LU? The water temp when I ran last weekend was 52 degrees. I suspect that after running for 30-40 minutes and shutting down, the cold water was sucked in as the LU cooled. ALSO... what parts do I need (or can I get) to service the water pump? The seal above the pump on the spline shaft does not look good, but the spline shaft is not corroded. The impeller seems to be in good shape, still flexible after all these years. Do I really need to replace it? One more thing... should I replace the water hoses at the lower back of the engine for preventive maintenance? Is there much pressure applied to them from the water pump? They appear to be in good shape, but also appear to be original. Appreciate the help guys...
 
Order seal kit or all the seals for the lower unit.---------It would be FOOLISH to think that you do not need a new impeller !
 
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