Prop Spin…Just Barely.

I am in process of getting a boat ready to sell. It is a 1989 SeaRay Seville Mid Cabin with a rebuilt 2009 Mercruiser 4.3L. I feel like everything on this boat has been replaced since I have owned it the past six years. Now we have kids on the way, and I want to sell it. The problem is I just fired her up for the first time since 11/14 and while she runs good I am not getting good prop spin when I rev the engine on a fake a lake. The last time I had the boat in the water was 2014, and at that time I remember loosing power under load where the engine would rev RPM’s but the boat wouldn’t move forward or backwards very well.

I have been looking at forums, and researching this. I am not a mechanic by any means, and I am a little outside of my comfort zone with this type of boat and engine.

As much as I hope it is just a spun hub inside the propeller, I am prepping myself for the worst case scenario and think it could even be a spun engine coupler.

Does anyone have experience working on these motors or boats? I am willing to pay the right person to diagnose the problem, I just want to avoid the marina’s if possible (@ $179+ hour) and limit the amount of money I put into this thing since I am trying to sell it.

I am open to any ideas or advice.

Thanks!

First thing I would do is bring the prop in and have it inspected. If it is good then you probably have something internally wrong.

However from your description my bet is on the spun hub.

Easiest way to check if it’s a spun hub is to draw a line across the prop and hub, take the boat out and run it, and see if the line is still lined up or if it’s moved. That would be where I’d start.

Nick, the easiest way to narrow this down is to take the prop off and take it in to the nearest prop shop and have them check for a spun hub. That’s the easy solution even if it costs a few bucks.

Or… This is fairly easy to check yourself if you have a way of testing the prop in the water. I’m not sure what you mean by a “fake a lake”, is this some kind of test tank?

To test for a spun hub, simply use a dab of paint to make index marks that mark the position of the prop and the hub. Then put the boat in the water and test. If the index marks are not still together after the test, you have a spun hub.

Based on your description, this is the first and most obvious thing that I’d check. There’s no use going into “what ifs” until the most obvious and likely scenario is checked.

Grouse

I beat you to the punch, TFG.

Check the prop hub first for sure but it is not that uncommon to have the coupler go out on the engine. Which really isn’t that bad of a job depending on how the boat is designed as to how easy the engine is to pull.

Ok great, thank you all for commenting. The fake a lake is just the muffs I hook up to the hose. If I can access the back of the engine, I will make the marks and see if they line up after doing a on the water test. I should be able to get to that later in the week and will provide an update. I have some videos of what I am experiencing, maybe I can get those to post.

Boat is working, now in the water!

Good news, now get it sold. Be sure to include the Gremlins in the sale so your next boat doesn’t have any issues.

I have a guy traveling three hours this Friday to come look at it!

What was the problem?

It was an issue with my Merc throttle that caused it to stick in neutral of all things. As for the engine possibly losing power under load, to be determined. Boat moves in the water nicely though!