7.4 l mercuriser 2000 arc Maxum

[Bobportante]

Hey all, I’m having an issue I’m hoping i can get some help. I have a 2000 Maxum scr2800 with a single 7.4 mercruiser. The boat was running fine on my way out to the bay today nothing out of the ordinary happened and on the way back I couldn’t get over 5mph the rpms were moving and got up to 3000 but the boat wouldn’t accelerate. Any ideas?

[Gugi47]

Welcome to the site.
Any noise?

[Bobportante]

No the engine sounds fine once I try and push it I get a slit rattle tho

[mmwjr]

Welcome aboard

So the engine was turning 3000 rpm and the boat was going 5 mpg, correct? What outdrive? Sounds like either a spun prop hub or engine coupler.

[Bobportante]

its a bravo 3 dual prop drive

[mmwjr]

Originally Posted by Bobportante

its a bravo 3 dual prop drive

B3 has solid hubs so it’s the coupler. The engine needs to come out to replace it.

[Gugi47]

That's why I ask for any noise.
I guess is the engine couplet.

[jparsons121]

Any smell of burnt rubber in the ER. Coupler spinning will usually be accompanied by a strong smell. To check prop, make alignment mark the outside hub of the prop and on the nut/shaft. I use a small punch to make the marks.
Note the alignment of the marks and make a pull in gear simulating the normal operation. Shut down and observe the marks. If they aren't aligned anymore, the prop hub is slipping.

[Bobportante]

Thank you all for the advise, I will update you when i diagnose the problem for sure.

[Bobportante]

it had a little smell of possibly burnt rubber and some one on the boat said they did see a little dark smoke from the stern.