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Propeller shaft play??

barkyboy

New member
Hello all. I recently did an oil change on my 1991 Johnson 150 lower unit. When I opened the lower drain plug a large volume of water came out approx 1 pint, followed by some black sludgy oil. The magnetic screw had no metal filings on it to be concerned about.. I did a pressure and vacuum test on the lower unit and it held steady at a high pressure. I refilled the lower unit with new oil. I proceeded to check the propellor shaft by rocking the propellor from side to side and I did notice a slight amount of freeplay, maybe 1/8 inch. Do I have anything to worry about? Should I run this motor for a few hours then recheck my lower unit for water invasion? Where would thew source of my leak be if my pressure checks oK ? Are there any recommended tests that I should do before I take the boat to the water?? Response is sincerely appreciated.
I did notice on the lower unit body what appears to be a paint discoloration and flaking, probably from overheating in the area of the prop shaft, but the last time I run the unit it ran ok. I just dont want to experience and lower unit seizures so I am asking for advice and suggestions. I have pretty good mechanical skills although I am not a Boat expert.I can pretty much follow technical instructions quite well.
 
Most common place for leakage, unless fishing line in propeller, is the drive shaft seal, which you need to remove the gearcase to check.
I would have re-sealed the unit!
Why do people check the gear oil before going out after storage?
Should be checked when hauled out and parked after use as part of the flushing. Storing gearcases with water is not a good idea.
 
no I did a static pressure test. Closed top plug and applied pressure to lower plug. Tested up to 100psi and gauge held steady.
 
When you did the pressure & vacuum tests did you rotate the D/S, Prop shaft and shift it ??

Reply to Boobie -no I did a static pressure test. Closed top plug and applied pressure to lower plug. Tested up to 100psi and gauge held steady.
 
For water to enter, it must be a vacuum leak and not a pressure leak.
If you have radial play (sideways) on your prop shaft -tear it down and expect to change some bearings together with the seals.
 
At 100 psi your lucky you didnt blow a seal you only need 15 lbs max shift the gears and crank on the starter if it holds the 15 lbs for 15 mins your good to go just keep the gearcase topped off check the level often and like was said change the oil before you store it for winter you dont want to crack the gearbox. It is also good to pull the prop once a year and clean/grease the splines before storage.

Thanks for the tip. Will try pressure test again the way you recommended.:eek: . I live in Florida, we don't store our boats for the winter.
 
Thanks for the tip. Will try pressure test again the way you recommended.:eek: . I live in Florida, we don't store our boats for the winter.

No need for another pressure test. It it was leaking under pressure, you would have oil all over.
Test with vacuum, and use the upper level hole. Remember to turn the flywheel as well as the prop shaft.
 
looking at the propeller from the back the play is from left to right.

Don't bother with any more pressure or vacuum testing. You need to have the lower rebuilt. It will probably be better and cheaper in the long run to replace the lower with a new aftermarket unit from SEI. Comes with a 3 year warranty.
 
sorry for the opening of old post but this is ridiculous
Daft comment to say it will be cheaper to buy a new gearcase rather than rebuild it.. new bearings and a seal kit is not that expensive. some people have zero idea of cost of a brand new gearcase....
 
sorry for the opening of old post but this is ridiculous
Daft comment to say it will be cheaper to buy a new gearcase rather than rebuild it.. new bearings and a seal kit is not that expensive. some people have zero idea of cost of a brand new gearcase....
8 year old post!!!
 
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