Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Lower unit inspection
Posted by rwhitejr on 02/16/08 - 5:08 AM
#1
Hello all,
Does anyone know of any checks I can perform on the lower unit to tell if it is in good working order(without putting it on a boat and running it). This is a backup motor I have aquired and has been sitting for some time and I want to assess if it is worth rebuilding and how much work it will need. It is a 1987 evinrude 88 hp.
Thanks, Rich
Posted by Derwd24 on 02/16/08 - 8:33 AM
#2
First thing I'd do is shift the lower unit by hand (if it's off the engine) while turning the shaft to see if it's working smooth or if you feel any binding. A visual inspection can tell you a lot too. Look for signs of oil leakage around both the main and prop shaft seals as well as cracks in the housing, intake screens, etc. Then I'd drain the gearcase oil and inspect it. Look for metal shavings and signs of water intrusion, which produce a somewhat milky color fluid. I'd also puill the water pump off and inspect the impeller (you need to do this anyway to check the top seal) And the shops will pressure test the lower units to check the integrity of the seals.
Others may have more ideas on testing.
Posted by rwhitejr on 02/18/08 - 7:08 AM
#3
Thanks Derwd24,
I will do as you have reccomended, I turned the prop by hand and it had no resitance I didnt know if that was good or bad or maybe in neutral? Anyway thanks for the input.
Rich
Posted by MW on 02/18/08 - 12:56 PM
#4
I had an 87 48 spl, replace the lower unit oil drain and vent screws with new ones, the new ones have magnets on them to catch any metal shavings.
mw
Posted by Derwd24 on 02/18/08 - 8:11 PM
#5
The way to tell if it's in neutral is to watch the drive shaft and see if it spins when you turn the prop. You can also shift it into forward and reverse by moving the long thin rod that's in front of the drive shaft up and down (only moves about an inch) to engage the gears. If memory serves, up is forward and down is reverse, middle is neutral. If you pull up on the shift rod but it won't move. try and turn the prop while moving the shift rod into gear. Then you can get a sense if there's any binding in forward or reverse when you turn the shaft in gear. It'll be harder to turn the prop as you'll also be turning the gears, drive shaft, and water pump. Just don't rotate the shift rod as you're moving it up and down because it's threaded on the bottom end and set to a predetermined height for correct engagement.
Edited by Derwd24 on 02/18/08 - 8:26 PM
Posted by rwhitejr on 02/28/08 - 5:47 AM
#6
Thanks for the advice guys, it was in nuetral so the prop spun free. So I drained the gearcase fluid wow that stuff smells! But no metal shavings and the fluid looked normal, good sign.
I want to clean the area around the waterpump area(pretty nasty looking). is it ok to just wash it out with water or can that get water in the gear case? Also the impeller seems to be stuck on the shaft, any ideas on how to get it off, I tried pliers and also screw drivers but no luck and I dont want to damage anything.
any help appreciated.
Thanks, Rich
Posted by Derwd24 on 02/28/08 - 6:42 AM
#7
Glad it's working out, things sound in good shape so far! The clean gear oil is a great sign.
Since you still have the impeller on there, I'd recommend putting the housing back on, and bolt it down lightly before cleaning up. There are two seals on the shaft below the water pump plate (right below the impeller) and if the shaft is perfectly straight while you clean it up with water, there's less chance of any seeping in.
If the area you want to clean up is black and kind of sooty, you probably should check the upper and lower rubber seals on the exhaust housing while you're there. The exhaust could be leaking in there and that's what's giving you the accumulated crud. Unless you meant it's corosion from salt?
My last impeller was stuck on the shaft too, and refused to come off. There's a metal core to the impeller, so I cut off a vane to get to the core (I think it's brass?) and then cut a (somewhat vertical) groove in that, used a flat blade screwdriver to open up the cut, and it came right off when it split. If you can locate the plastic woodruff key by looking down from the top and make your cut there, it's thinner and easier to split with the screwdriver wedge. Others may have different/better solutions, but that worked for me.
Also, would recommend a whole pump kit instead of just swapping the impeller. Good luck!
Edited by Derwd24 on 02/28/08 - 6:57 AM
Posted by MW on 02/28/08 - 9:18 AM
#8
Don't forget to put a dab of "Mr gasket" on the plastic keyway to hold it to the shaft when putting the new impeller on, change out the "Wear plates" too, even a few thousant's of an inch on each "Wear plate" can reduce water pump volume. When sliding the impeller on the shaft and into the housing, put the gear selector carefully in "Foreward" twist the prop in the foreward direction, this will spin the drive shaft bending the vanes on the impeller, and twisting them slightly, then the impeller housing should slide right on the impeller, a little warm water and soap on the rubber impeller is sometimes needed to slide it into the water pump housing. remember you're working with "Aluminum" when replacing the lower unit, DO NOT OVER TORQUE the bolts.
mw
Posted by Binkie on 02/28/08 - 4:13 PM
#9
A friend picked up an antique outboard (`56 Evinrude 30hp) he saw in upstate NY recently. He said the owner said it ran good but was stored for a few years. the motor turned over easily and seemed to have good compression. My friend said he used to own a marina years ago, and knows outboards. The motor was in neutral when he turned it over with the recoil. When He brought the motor by I noticed the the prop wouldn`t turn in neutral at all. I said, Oh Oh, here`s a problem.
The gears are rusted, and they were rusted solid. No water or oil in the gearcase at all. disappeared years ago. Good thing I got it cheap, it needed a new gearcase.:(
The moral of this story is if you are looking to buy an old motor, check to see if the prop spins in nuetral. It should easily. LOL
Rich
Posted by Binkie on 02/28/08 - 4:20 PM
#10
A trick I use when sliding the waterpump housing over the impeller is to coat the impeller liberally with hairgell. Is really slippery stuff, and cheap, and the housing will slip right on when the shaft is turned slowly in forward rotation. Hairgell disipates almost instantly when in contact with water.
rich