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1979 Model 200 20hp shaft spline help

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raf2325

New member
Hey guys!
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First time posting here. I have a Model 200 20hp outboard that I was changing the water pump impeller on and notice there is some pretty good wear on the splines.

Is this sort of normal for a 45 year old motor? Is the crank shaft causing this wear? I would assume the crankshaft would be harder than the driveshaft.
Can I still run this or is it junk?
 
racerone said:
Re-assemble with grease on the splines.----Good for another 45 years if greased every 5
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That is exactly what I Planned. Grease it up and run it. Glad to hear you don't think this is too bad. I heard the 200s were known for spline wear.
Wasn't sure what is considered bad.

Thanks for the help!
 
This is neglect, splines wear from lack of lubrication which would be done at each impeller change, good that you noticed the splines, check your gear oil for water, because all pre-1976 small Mercs were using carbon steel driveshafts that tended to rust below the waterpump base in the seal area that could damage the seal from pits allowing water in or gear lube out, best to pressure test it to 5-7psi if you can, using the correct tool.
 
fitz73222 said:
This is neglect, splines wear from lack of lubrication which would be done at each impeller change, good that you noticed the splines, check your gear oil for water, because all pre-1976 small Mercs were using carbon steel driveshafts that tended to rust below the waterpump base in the seal area that could damage the seal from pits allowing water in or gear lube out, best to pressure test it to 5-7psi if you can, using the correct tool.
Click to expand...
Thanks for the reply.

The guy I bought the motor from days it sat for 5 years or so. There was very little grease in the splines and it had going hard. This one is a 1979 by the way.

You think it's got some life left in it?
 
They switched to stainless steel shafts in 1976, so that rust problem was eliminated. It all depends on the care they've had and if they were run in freshwater verses salt water. I have 1953 Mercs that start on the second pull, its all relative!
 
fitz73222 said:
They switched to stainless steel shafts in 1976, so that rust problem was eliminated. It all depends on the care they've had and if they were run in freshwater verses salt water. I have 1953 Mercs that start on the second pull, its all relative!
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No signs of rust. Just some decent wear on the shaft splines.
 
There will be rust in the crankshaft splines.-----Clean that spline.----Re-assemble with grease.----Go fishing.----Donate the motor to your grandkids in the future.
 
raf2325 said:
That is exactly what I Planned. Grease it up and run it. Glad to hear you don't think this is too bad. I heard the 200s were known for spline wear.
Wasn't sure what is considered bad.

Thanks for the help!
Click to expand...
If we are looking at the top of the driveshaft that inserts into the bottom of the crankshaft, grease the sides, no build up of grease on the top as it can prevent the lower unit from going all the way in when reinstalling the LU......so says OEM repair manuals!
 
Just an update.

I did grease and reassemble the motor and got a chance to take it out the other day. It seemed to run well! Though it did seem a bit noisy. Almost like a high-pitched rattle.

Could the worn splines be making a noise? I thought no. Perhaps I'm just not used to the old two-strokes haha. It seemed to shake and vibrate at idle as well. Any thoughts?

Thanks again for the advice
 
Could be the recoil starter rattling, a starter pawl as an example, the mounting pins get damaged from people just yanking on the starter rope without engaging the pawls first. , does your engine still have the insulating blanket in the wrap around cowl? These engines can get pretty "tinny" sounding without the blanket.
 
fitz73222 said:
Could be the recoil starter rattling, a starter pawl as an example, the mounting pins get damaged from people just yanking on the starter rope without engaging the pawls first. , does your engine still have the insulating blanket in the wrap around cowl? These engines can get pretty "tinny" sounding without the blanket.
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Okay, I'll check the starter and the insulation. I suspect the insulation is deteriorating. It doesn't seem to make the noise at idle. Just vibrates. I'm assuming any engine damage would be there at low rpm, as well. "Tinny" is the perfect way to describe it.
 
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