4.3L Mercruiser Alpha One only idles along

[specmkr]

I can shift into forward and reverse, and can idle along, but when I throttle up at all the engine just revs and the boat goes at the same idle speed. I am not a do it yourselfer and will have someone look at it, but just wondering what it may be. Only has 128 hrs on engine and was working perfectly before this started.

 

[paultjohnson]

Re: 4.3L Mercruiser Alpha One only idles along

Sounds like you spun your prop hub or maybe the coupler . Have you checked either ? Hopefully its the rubber insert on the prop...spun prop hub

 

[burp]

Re: 4.3L Mercruiser Alpha One only idles along

A quick and easy way to see if it is a spun prop hub is to draw a straight line with a permanent marker across the aft end of the prop...across the prop barrel/body, prop hub, and the end of the prop shaft. Put the boat in the water and try to go. Afterwards, recheck the line. If the line no longer lines up, pull the prop and have it repaired/re-hubbed.

 

[specmkr]

Re: 4.3L Mercruiser Alpha One only idles along

I have a solid hub prop on it right now as the old prop was beat up pretty bad. Not sure what a coupler is. Hopefully it is something this simple though. I will pull the prop and see what it looks like though. Truthfully, I was so irritated, I just wanted to get it home before I broke anything else. Just bought the boat recently and this is only the third outing.

 

[Brewman61]

Re: 4.3L Mercruiser Alpha One only idles along

Not sure what a coupler is. Hopefully it is something this simple though.

Coupler is on the flywheel (back of the engine) basically the link between the splined shaft on your outdrive and the engine. Replacement is quite labor intensive, so keep you fingers crossed it's not the coupler.

 

[specmkr]

Re: 4.3L Mercruiser Alpha One only idles along

fingers crossed....

 

[Pete104]

Re: 4.3L Mercruiser Alpha One only idles along

What solid hub prop?

 

[specmkr]

Re: 4.3L Mercruiser Alpha One only idles along

Pulled the prop today. Definitely spun the hub, thank the Lord. New prop ordered and hitting the water next weekend. Thanks guys for your input. This was a spare and I believe the wrong diameter. Ordered the original pitch and size.

 

[specmkr]

Re: 4.3L Mercruiser Alpha One only idles along

Just meant that the hub is not removable. It's all one piece.

 

[burp]

Re: 4.3L Mercruiser Alpha One only idles along

The Bravo 3 props are a single piece......but most props for the Alpha outdrive have a hub.....which is a rubber piece that is between the splined sleeve and the prop. The rubber hub piece is pressed into the prop and can be replaced by a prop shop.

 

[specmkr]

Re: 4.3L Mercruiser Alpha One only idles along

Thanks burp for the info. This has definitely been a learning process for me. I have found a great resource/mechanic here in the Raleigh area who has helped me tremendously. Great guy. Thanks again