Engine coupler or dog clutch or something else

[Kchomes1]

Few weeks ago went boating to break in a new sei upper unit. Everything went well until the end of day when at about 4000 rpm lost power and rpms increased.. I figured it was a spun prop. Changed the prop put back in water today… ran great for 45 minutes then at about 4000 rpm same thing except some white smoke from back of boat not sure if this is from excessive rpm or what… after that could not get above 2000 rpm without it losing power and raising rpms… pulled stern drive the splines looked fine
Engine mercruiser 350 alpha
Outdrive alpha one gen 2

Thanks in advance

 

[dubs283]

clutch dog - not likely
engine coupler - possibly
something else - perhaps

did the white smoke have a burnt rubber smell to it?

 

[Kchomes1]

I’d say so it definitely smelled…tried to check and see rubber shaving but got dark on us

 

[dubs283]

may be that the hub spun in the engine coupler. if you can mark the rubber hub and the outer steel area then run the boat and see if the marks are no longer lined up

 

[Scott06]

may be that the hub spun in the engine coupler. if you can mark the rubber hub and the outer steel area then run the boat and see if the marks are no longer lined up

Pull the drive and inspect coupler for rubber pieces and screwed up or pointy splines. Take top off drive look at upper gears see if they are ok.
whit smoke could be overheating if coupler is slipping or drive gears are gone vertical shaft in outdrive wont be spinning and thus water pump impeller wont be pumping

 

[Kchomes1]

Started getting ready to pull engine. Confirmed it is the coupler…rubber everywhere

 

[Scott06]

Started getting ready to pull engine. Confirmed it is the coupler…rubber everywhere

Was the alignment checked when the drive was replaced?

 

[Kchomes1]

Yes… when the old drive failed it locked the drive shaft and I believe that’s when the engine coupler spun and that was the beginning of the end

 

[Scott06]

Yes… when the old drive failed it locked the drive shaft and I believe that’s when the engine coupler spun and that was the beginning of the end

Makes sense as thats whatt he coupler is supposed to do.

Depending on your boat you may not need to completely remove the engine, just lift it up and twist it 90 or pull it forward enough to remove the flywheel housing.

 

[Kchomes1]

We are attaching hoist this afternoon will see if we can get away with not removing completely