4.3LX No prop spin on throttle- Bad coupler?

Conspiracy

Cadet
Joined
Jul 12, 2020
Messages
7
Really here for confirmation...here is the scenario.
Had the boat out on the lake Saturday, running well around a small lake 4000-4800 RPM across smooth water. We go into a corner (the lake is basically an oval track with an island the length of the middle) across another boats wake. I slowed a bit to cross the wake and when we were making the turn the engine revved up and we lost power.

A lot of smoke and terrible smells later, we confirmed no fire and let the engine sit for a while. Prop was attached, the engine would go in gear and we even move a bit but any amt of throttle and nothing.

Temp and oil pressure both seemed fine before i’m the incident.

I’ve checked the prop bushing and unfortunately that doesn’t seem to be the issue. From what I understand the engine coupler is the next culprit. I’ve never removed an engine before but I understand if you follow the manual and have the tools, the coupler isn’t a terrible job right?

Any other ideas?
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,443
Other possibilities are broken drive shaft in the drive or toasted gears. In these scenarios the input shaft to the drive (from the coupler) won't turn when you spin the prop. You can pull the top cover of the drive and take a look, and check your gear oil. Then either way the drive is coming off. Once the engine is out the coupler takes 10 minutes to replace.
 
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