Mercury 500 50hp

Outboard designs up to 14'

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shain
Posts: 2
Joined: Sun Apr 24, 2016 2:40 pm

Mercury 500 50hp

Postby shain » Sun Apr 24, 2016 2:49 pm

I would like to know how to install the plastic cam lobes for the shift shaft on a Mercury 500 50 hp. The lu was dropped put not in forward on the control unit and the top plastic cam fell out without seen its original position. Also what direction should the bottom cam be in and in what gear FWD RWD or neutral. When installing the bottom unit i never get all 3 positions Anybody have a picture or manual on this procedure. It is a Mercury 50 hp 2 cycle Serial 2742603. Thanks

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Roberta
Posts: 5888
Joined: Tue Jul 31, 2007 5:23 pm
Location: East Troy, Wisconsin

Re: Mercury 500 50hp

Postby Roberta » Sun Apr 24, 2016 4:45 pm

Here is a link to a thread I wrote on repairing the Merc 500 lower unit. Pictures were originally posted on image shack and I needed to repost them so the captions are a little out of whack. You should be able to follow along with you unit. Hope it helps.

Roberta

viewtopic.php?f=9&t=13928
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

shain
Posts: 2
Joined: Sun Apr 24, 2016 2:40 pm

Re: Mercury 500 50hp

Postby shain » Mon Apr 25, 2016 1:05 pm

The Picture you took looking into the gear case you can see where the cam is that operates the follower cam that moves the ratchet. Does that cam have the flat edge down or the cam lobes down. When the cam lobes are up has a hole for the shift shaft to sit in which does look like your picture but i then see no reason for the cam lobes facing up or into the upper part of the housing as they have no purpose. The picture of the bottom cam to show the line from the cam lobe to a bolt would be nice to see the picture if you still have one Thanks again Shain

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Roberta
Posts: 5888
Joined: Tue Jul 31, 2007 5:23 pm
Location: East Troy, Wisconsin

Re: Mercury 500 50hp

Postby Roberta » Mon Apr 25, 2016 2:45 pm

Not sure I quite understand your questions. The cam in the gearcase rotates in a horizontal position with the shaft in a vertical position. The cam should be pointing to the left side of the housing with the detent groove facing aft. The upper cam for the reverse locking latch (prevents the engine from lifting in reverse) should be set on the shifting shaft so it allows the latch lever (located above where the lower unit separated from the housing, to be fully down. This cam lifts that upper latching rod to latch the motor to the transom mount to prevent it from lifting. If you have the lower unit in forward as I describe in the thread, you can place that cam on the splined shaft in the position shown in the picture. It is important that the lower unit be in that forward drive position and the cam in the detent like I describe. Read the thread carefully.

The cam I removed for the latch was plastic and I replaced it with a metal one as shown in the picture.

I highly recommend you get the repair manual for this engine. It really helps.

Here are some pics that may make this more clear.

Roberta
Attachments
Lower unit 2 010.jpg
Line up the bottom of the slope on the cam to the front bolt on the water pump.
Lower unit 2 004.jpg
You can see the detent on the cam. This is the position for forward.
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".


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