Refitting lower unit

[2mate]

Hi there,

I've got a 1996 mercury 30hp elpto serial no 09885943.
I bought the engine with a broken lower unit and have since found a replacement. The trouble I'm having is that when I do the lower unit up tight to the midsection you cannot turn the engine over. I have tried putting the original lower unit on and am having the same problem. I've left the selector shaft undone so I know it's not that catching. The drive shaft on the new unit is a couple of mm shorter but this should make it go in easier if anything. The shafts are definitely engaging as I can turn the flywheel and see the shaft/prop turning its only when the bolts are tightened I no longer can turn it.
Any ideas?
Cheers

 

[Iceman66]

Re: Refitting lower unit

Maybe the splines inside the crankshaft are twisted,
or something that shouldnt be in there is stuck there,
or full of corrosion/dirt ,
and the driveshaft doesnt slide smoothly ALL the way in.

Maybe earlier owner has forced it into its place and didnt care, could be the reason why the original lower unit has broken.

 

[jslu]

Re: Refitting lower unit

Check for excessive amoun of grease in the crankhaft female spline. Too much grease can exert excessive downford force on to the driveshaft and hence to the lower unit. hard to see up there, but take a peek.

I've got a 1996 mercury 30hp elpto serial no 09885943.
I bought the engine with a broken lower unit and have since found a replacement. The trouble I'm having is that when I do the lower unit up tight to the midsection you cannot turn the engine over. I have tried putting the original lower unit on and am having the same problem. I've left the selector shaft undone so I know it's not that catching. The drive shaft on the new unit is a couple of mm shorter but this should make it go in easier if anything. The shafts are definitely engaging as I can turn the flywheel and see the shaft/prop turning its only when the bolts are tightened I no longer can turn it.
Any ideas?
Cheers[/QUOTE]