Original prop for 74 v step 165 hp 6 cyl?

[Dodgerrr]

Hi Guys. I finally had the chance of taking out the old boat only to hit a rock and damage the prop.
Specs:
Prop #18-78122-21
Engine 165 Merc inboard 6 cyl.
Max rpm 4100.
Max speed 38 mph, I think.

Now when I went to install the prop I noticed that the splines did not protrude past the prop at all for the brass locking collar to engage with. I guess last the few years, the only thing locking the nut from spinning off was nothing at all? Some one said the tapered spacer may be too thick which results in an inability to lock the nut properly.

I think the guy I bought the boat from did some swapping before I bought it. BTW, I know nothing.

Question? Does any one know or have the original prop or information that may have come with this boat when new? Is this the correct prop. I think max RPM should be around 4400.

This also takes for ever to get up on plane. It also steers terrible always pulling hard to the left. Yes and there is some klunking in the shafts when I steer sharp and hard at hi speeds.
I swear I need 40 acres to get this thing turned around. It is easier to stop, slowly turn and then gun it back up to speed.

Your thoughts are appreciated.
Dodgerrr.

[spareparts]

sounds like you need a 19 pitch prop, try to get the rpm to 4400 -4600. Watch that clunking, it coiuld get expensive. the inline 6 set ups didn't come with power steering, but they used a long trim tab to offset the steering torque. be carefull with some props as some of them will hit the extra long trim tab. BTW, the trim tab needs to be adjusted to offset the steering torque

[Dodgerrr]

Originally Posted by spareparts

sounds like you need a 19 pitch prop, try to get the rpm to 4400 -4600. Watch that clunking, it coiuld get expensive. the inline 6 set ups didn't come with power steering, but they used a long trim tab to offset the steering torque. be carefull with some props as some of them will hit the extra long trim tab. BTW, the trim tab needs to be adjusted to offset the steering torque

That my friend makes a lot of sound advice. The boat does have some big a** trim tabs.
I guess you use them when travelling in a straight line, right? Turning with the tabs lower in the water wouldmake it more difficult, correct?

I replaced the engine myself last year and a friend said that I should have it sent in for exact alignment.

One other thing... there is a tab above the prop which has very much disintigrated. How important is this part?

BTW, thanks for your quick advice.

[tsubaki]

That's the one he's talkin about, it helps equalize the steering torque. If it's a right hand rotation it may be turned slightly starboard to help reduce steering pull, if left handed to port.

Some people want a boat to pull toward a circle when the steering is released, you will have to adjust it to your needs.

[macojoe]

You can get the steering zinc at any boat store they all have them.

My 1975 V20 Cuddy 165 I/O used a 17 pitch when I got it, but I liked a 15 1/4 X 15 much better for over all use, got up on plane in just a few seconds.

[spareparts]

that is the one I was talking about. the straight 6 drives used a bigger one than the regular tab, it might be a little harder to find, but go with the big one if you can find it

here it is....
http://www.boatzincs.com/MER34127.html

[Dodgerrr]

You guys have been great, thanks for all your help.
I know how important it is to try and upload a picture so here one is...I think it may be kind of small though.
Dodgerrr.

I'll try again.

[axespino]

Where are you located at I have two lower units and a used engine from 73 V20's and probably some controls.