Mercusier MC-R Lower Drive not going back together after new pump install

[This Ship of Fools]

Have a 1976 Cobalt Mercrusier 233 with what I believe to be the MC-R drive I am replacing the sea water pump in the lower unit I purchased a Sierra 18-3317 kit everything looks close to the same but could not get the lower half of the new pump to set all the way so I reused he lower half of the old pump everything went together just fine I been trying to reinstall the lower drive to the upper drive Shift control is in forward shift selector spine in lower drive turned to forward ( lock prop so if prop is turned counter clockwise the lower drive shaft will spin .Have tried turning prop while installing This lower unit has a loaded pin on top that is very hard to compress if at all Is it this load pin stopping the drive from going in? The closest I can get the drive is to the point of the mating studs are just flush with the upper housing Any help will be greatly appreciated

 

[Eric 3.7LX Alpha 1]

The pre load pin should not stop you in any way.

you want to rotate the splined shift shaft on the lower unit clockwise and rotate the prop CCW until it locks and hold it there using your hand or a bungee cord.

That will hold the lower in Forward....

the Shift shaft in the upper should be straight front to back which will be in forward...

When you push the lower unit up to the upper half, if you get hung up slowly rotate the prop further CCW to align the splines and it should mate right up.

PS... you should pull the entire drive off the boat. So you can check alignment of the gimbal bearing, grease it, and the u-joints and make sure water has not

leaked into the bellows since the last time it was pulled off.

 

[This Ship of Fools]

Thanks for your response Tried it again but still would not go . so I removed the copper water supply line then tried and it went right together. I disassembled the pump and thought maybe there was a difference in heights of the new pump with the copper pipe attached but that all matched up. It appears that the connection for the copper pipe at the pump is very tight and that is what is making things difficult Good point about the upper drive inspection Just waiting on a new pump gasket as I damaged one taking apart the pump I will let you know Thanks again

 

[Bt Doctur]

a touch of grease on the rubber bushing in the pump cap or a bit on the copper tube works wonders

 

[This Ship of Fools]

No Title

Well got her to go together .I tried greasing the pipe and pump housing connection Still would not go so cleaned up the old pump housing put the new impeller in it put it all together and she went right in. Pump works great . But now I have a new issue of the engine running way to cold the temp gauge doesn't get past 100 degrees. The old impeller had no paddles left on it when removed I'm thinking now that maybe pieces of that impeller may have made their way into the engine and maybe have the thermostat suck open Picture of same engine I have below ( sorry about the clarity of the pic)

Anybody have any suggestions

 

[Watermann]

Take the t-stat housing apart and check. It doesn't look like you have a PS pump and cooler so the pieces might just be stuck in the t-stat if you're lucky.

You really should replace that blower hose or at least get it connected to the through the transom cover vent.

 

[Fishermark]

If you were missing fins, then yes, you definitely need to track them down. And yes, the thermostat housing is where you are likely to find them. Although I doubt they are the culprit for keeping you engine too cold. They do not usually make it all the way to the actual thermostat. Here's a pic of mine after an impeller shredded: