outboard motor parts

DIY inboard outboard boat motor parts & accessories

Johnson Evinrude Mercury Mariner Force Chrysler Yamaha Mercruiser OMC Cobra    

Home | About | Cart | Privacy | Returns | BPS Clubs | Outboard Troubleshooter | FAQ      

Parts Depts.


Chrysler Outboard

Force Outboard

Johnson Evinrude

Mercury Mariner

Mercruiser Stern Drive

OMC Cobra Stern Drive

Yamaha Outboard

Repair Manuals

Help, I cant find it!


Boating Classifieds NEW!

Manufacturer Links

The drive system on an outboard is very basic to that of an inboard/outboard. About the only things servicable by the average person would be changing the lower unit oil, and impeller replacement. Figure 1 shows the typical location of oil drain and vent plugs. Lower unit oil should be checked on an average of about three times a season for water/moisture content. When performing an oil change, remove both upper and lower plugs. When oil is drained, refill by way of the bottom drain hole only!. Fill until oil is seen exiting vent hole. Install vent plug first, then drain plug. This procedure will limit excessive escaping oil until drain plug is inserted. If you attempt to inject oil through the top vent plug, an air pocket will develop, and oil cannot enter and fill the lower unit properly. In a normal check, one might find that the oil has a dark blue or "burned" look to it. This is a sign of negligence toward regular service. One might also find that an ever so slight "milky look" may be present. This is usually considered normal from condensation. If oil has a heavy "milky" look to it, you obviously have a leak, and immediate attention is warranted. Resealing a lower unit requires special tools, so it is advised to have a qualified technician perform this task.
obdrive1thumb.jpg - 5665 Bytes

^Click to enlarge^
Replacing the water pump impeller Figure 2 can be a difficult task on some models, and a rather easy task on others. If after reading the manual for your specific application, you still do not understand what is required to remove and reinstall the lower unit, it would be best to let a qualified technician perform this task. After replacing the impeller, if everything does not go back together in a specific way when reinstalling the lower unit, you could be left pulling large amounts of hair out of you head in aggrivation when nothing works like it should.
obdrive2thumb.jpg - 10342 Bytes

^Click to enlarge^
Tilt/trim System

Most tilt/trim systems on outboards are pretty indentical in operation, but can vary in looks. Troubleshooting tilt/trim is very basic. If the trim motor runs, but the motor does not raise up or down, it is likely that the fluid level is low. If fluid level is normal, then the unit most likely has internal seal/valve problems and will require a qualified technician to reapair it. You might also check the manual release valve to make sure it is snug and not leeting the fluid bypass.

If the trim motor will not run, two things could be wrong. Either the motor is bad, or the solenoid/s are bad. A good rule of thumb to easily find out which the problem is, is by connecting a volt meter to the green/blue wire at the point where it enters the trim motor. With trim button depressed(assuming the ground is good), if volt meter shows 11 to 12 volts present, the motor has a problem. If volt meter shows less voltage, or no voltage, then either there is a problem with the power supply, or the solenoid/s are probably bad.
If you should have any questions about your drive system that may not be answered in this section, feel free to email us. We will gladly help you in any way that we can.