Merc Prop issues

pyro225

Petty Officer 2nd Class
Joined
Oct 1, 2014
Messages
191
Hi Guys,

My 80 merc has a 10" pitch prop. I have got a 19" prop i tried to fit...

I took the old one off and it had like a gold spacer on it... this would not fit the new prop - but the new prop seemed to have something built in to space it out the same...

I put it on drove it for about 500m and the prop seemed to seize and cut out.

What have i done wrong? or what am i missing?

Original:

25375667-1696-4D98-A343-0771ACAEC1BF.jpg



NEW:
696DCC61-E374-49A3-BC44-4F50C8C67A66.jpg
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,795
The gold "hoots" in your first picture is the thrust washer. Looking at the inside diameter you will notice that it's tapered. Look at the prop shaft prior to entering the lower unit and you will also notice a taper. The taper of the thrust washer must match the shaft taper, not the reverse (putting the washer on backwards) which will not allow you to get the prop nut on adequately. With no thrust washer the prop can slide too far forward and come in contact with the LU housing.

Measure the dimension from the front of the prop hub to the front of the prop housing on both props. Measure the length of the hub splined insert. If both dimensions are at or near the same, with your thrust washer installed properly, your new prop will work. If not, you need a different thickness thrust washer. Usually the newer props with replaceable hubs require a different washer but yours looks to be rubber cored and rubber cored so it should match.

Mark
 

pyro225

Petty Officer 2nd Class
Joined
Oct 1, 2014
Messages
191
ok well the lip on the washer slides into the original prop should i take it off and make sure its the right way around? the washer doesn't fit anywhere on the new prop - so i definitely do need another one?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,795
Did you make the measurements I asked for? While measuring, measure the diameter of the inner alum hub on both props. Looks to me like the OEM prop is wider than the new prop and allows for the insertion you mention. Insertion is not necessary as long as you have the thrust washer properly rotated and installed allowing the prop something to push against. Since you have your camera handy and know how to upload, install the washer properly, and the new prop and nut with the locking mechanisms and run the nut up SNUG ensuring that you get the locking ring lined up so that the points of the nut fit into it. Then take two pictures: 1. looking from the side at the interface of the front of the prop and lower unit casting....looking for proper clearance.

2. From about a 45 degree angle shoot the prop nut showing how everything fits and I'm looking for that and how much prop shaft thread you have protruding from the rear of the nut.

If all looks good then I'll come back with the comment to torque the nut to 55 ft-lbs and bend the locking tabs down. 3 is all you need and once you get your 55, just keep turning slightly until 3 tabs line up and lock her down.

Mark
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,463
You need one that's flat on "both" sides. Same thickness is fine. If tha one you have is that way it will work. Just pay attention to tha "tapper" of tha shaft and tha hole in tha washer....Think you said you ran tha prop without a washer???
 
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