Mercruiser 4.3 prop issue

[Bswiernik]

I have a 97 rinker captiva 182 with a 4.3 alpha one gen 2. My prop is very banged up and corroded, I can not read any numbers off of it. Is there anyway to know what was on it? I bought a 14 1/4 17p from the marina today, as I am going away this weekend and was looking to replace it before that. Any way of knowing what my performance will be? With whatever prop was on there I was at 4200 wot at 41mph lightly loaded. Thanks in advance.

 

[steelespike]

Prop size may be under the prop nut
​What hp? Very likely the 17 is way too light.
You will have amazing hole shot but you will have to be careful not to over rev.

 

[Bswiernik]

That's what I was afraid of. It's a 190 hp I believe. It's a 2 barrel carb. I took it off and looked under the nut, on the way to the shop to try and clean it up more. It's just so corroded it's hard to read.

 

[poconojoe]

I don't know if this helps... My boat is a Bayliner 185 bow rider it also has a 4.3L carb and alpha 1 gen 2 with 1:81 ratio. My prop is a 14 X 23P 3 blade. The boat weighs a bit over 2,100 lbs.

 

[Bswiernik]

That does help. Thanks. What's your top speed and rpm? How's the hole shot? Thanks.

 

[Bswiernik]

I used the Mercury prop selector and it suggests a 21 pitch. I generally run with 4 adults and a well stocked cooler. No water sports. Is this a good place to start? Or should I go with a 19? Thanks.

 

[poconojoe]

That does help. Thanks. What's your top speed and rpm? How's the hole shot? Thanks.

Our boat seems similar to yours. It runs great, gets on plane quick and I can throttle down to about 20MPH and stay on plane. Most of the time it's just me and the wife. The lake we are on is very rough most of the time. Unfortunately very rare we get a day where the water is like glass. That being said, I rarely open her up to WOT. I think the 14x23P is a good match for us. I know I've been up between 45-50 MPH but don't remember the exact RPM's. It definitely wasn't over revving. The weather this season has been terribly rainy and we haven't been out much. I was hoping to get out today and get some numbers for you, but it's pouring out again!

 

[Sea Rider]

Why don't you take it to a prop shop, they should be able to determine size and pitch. If combo was doing great hitting 4200 revs while lightly loaded buy same size/pitch new, assuming max revs achieved corresponds to max wot revs factory range for that engine


Happy Boating

 

[Bswiernik]

I don't really know where there is a prop shop near me. Here is what I found today.
14.25x17p. Rpm was way to high. Turned right around. No go for my setup.
14.25 x 19p. Rpm was 5000 and speed was 39 mph. Nearly threw me out of the boat when I got on it it had so much pull.

14.25x21p Rpm was 4600 and speed was 46 mph. Still pulled good out of the hole, and felt good through the whole rpm range. I left it on for now and that is what I'll be running on sacandaga lake this weekend.
Both props had the same load and are the same manufacturer. My Marina stocks some and let me try 3 before I decided which one to keep.

 

[steelespike]

I don't really know where there is a prop shop near me. Here is what I found today.
14.25x17p. Rpm was way to high. Turned right around. No go for my setup.
14.25 x 19p. Rpm was 5000 and speed was 39 mph. Nearly threw me out of the boat when I got on it it had so much pull.

14.25x21p Rpm was 4600 and speed was 46 mph. Still pulled good out of the hole, and felt good through the whole rpm range. I left it on for now and that is what I'll be running on sacandaga lake this weekend.
Both props had the same load and are the same manufacturer. My Marina stocks some and let me try 3 before I decided which one to keep.

Thats the way to do it if you can.Is speed by gps?
Calculations indicate your setup is about perfect. Showing a very respectable 8% slip.At 4600 if you go higher pitch It may become sensitive to
added weight and may struggle with water sports.May become fussy when trying to cruise at lower rpm.

 

[Bswiernik]

Speed is on GPS. Checked the tach against my snap on tach and it was within 50 rpm through the whole range. Thanks.