2005 merc xr6 150 lower unit install

[Dave Ervin]

I have a 2005 merc xr6 150 hp. My serial number is 1B029436. I just replaced waterpump. I cannot get lower unit to go back in. My buddy dropped the lower unit with gear in forward. Tried for a couple of hours to mesh the splines of driveshaft and upper hole. I need some sound advise on what I may be doing wrong...and what I need to do to get this back on. It is falling short about 2".
thanks Dave

[leonreno]

Are you turning the prop while pushing it in? If so and it will not go in make sure lower unit is still in forward or put both lower unit and motor in neutral and try that way. Also should check the bottom of powerhead with flashlight that the bushing/seal around the motor crankshaft isn’t loose.

[Bruce2]

Old water pump seal still stuck to water tube, also are you using the plastic water pump tube guide.

[JohnM64]

2" is pretty far out, and would seem to rule out gear shift coupling. As mentioned, check the connection from water pump outlet on lower unit to mid section, and use the plastic water pump tube guide. For safety and ease of install, tie off the lower unit to the top of the transom once the driveshaft is up and in - that will hold it in place while you inspect for alignment.

Not long ago I had a similar problem, eventually diagnosed as almost imperceptible burrs on the male lower unit driveshaft - the burrs prevented the driveshaft from seating into the crankshaft coupling. They were only found by running a fingernail along the splines - the burrs were on each spline, and quick touch up with a file allowed easy install.

After you get it together, water test it, and bring your tools to the ramp - if the water pump connection did not go together correctly, your water pump pressure will be erratic as rpms increase. If so, remove and reinstall.

[SilverFox579]

Are you turning the prop while pushing it in? If so and it will not go in make sure lower unit is still in forward or put both lower unit and motor in neutral and try that way. Also should check the bottom of powerhead with flashlight that the bushing/seal around the motor crankshaft isn’t loose.

^^^^

[aussiejake]

Check the plastic o ring thing hasn't moved and interfered with the hole where the shaft is meant to sit.

[Dave Ervin]

Yes using plastic tube guide. Yes we tried turning prop while push it in. I will put lower unit in neutral and motor in neutral. How do I get lower unit in neutral? Turn shift guide by pump? I will check driveshaft splines for burrs.
Thanks for everyone's help/suggestions
Dave

[leonreno]

Change lower unit by turning shift shaft in front of warmter pump. I use a vise grip with a rag around shift shaft to prevent damage to the splines.

[Dave Ervin]

Thanks for info, put vise grips below splines, turn which direction in smal amounts? What is best way to turn flywheel?

[leonreno]

It doesn’t turn much, less than a half turn, more like a 1/4 turn. If it’s in forward turn it the only way it will turn, in other words I don’t remember which way to turn it, sorry. Many will hook a remote starter to the starter to bump while pushing in lower unit, or if you have a helper, a socket and breaker bar on flywheel nut works.

[Dave Ervin]

Thanks Leon! I will post when I get this fixed, hopefully Tuesday.

[paulrodbender]

As said before, look up with a flashlight. I had to use a piece of tubing to realign the washer that's up near the power head on my XR4.

[EuropeanAM]

Look up in there with a flashlight- going to bet the lower o-ring carrier has come off the end of the crankshaft, and is sitting across the opening for the driveshaft (preventing you from getting the driveshaft into the splines).

Fairly common when gearcase hasn't been off for a while, or the removal was awkward/over-zealous.

[Dave Ervin]

That is what has happened. The crankshaft o ring carrier is loose and not around the end of crankshaft . How do you fix this? This is what is preventing the shaft from going into shaft lineup with crank? Can this be put back on?

[Dave Ervin]

It doesn’t turn much, less than a half turn, more like a 1/4 turn. If it’s in forward turn it the only way it will turn, in other words I don’t remember which way to turn it, sorry. Many will hook a remote starter to the starter to bump while pushing in lower unit, or if you have a helper, a socket and breaker bar on flywheel nut works.

see my recent reply, lower O-ring carrier came loose, how do I put it back on bottom of crankshaft?
Dave

[leonreno]

I have not done it but I believe some people have taken a long wooden rod (such as a broom handle) to push it back in place, probably a little cursing involved too. If that doesn’t work, may have to remove powerhead to fix. But, maybe some else has a suggestion to fix it.

[EuropeanAM]

Custom-fashioned PVC Tool (takes a little grinding on a union, and a piece of pipe).

Put tool up in there, set trim LEVEL, and very very carefully align perfectly before tapping back into place.

​One shot chance at this... if it doesn't work, the powerhead will almost certainly be coming off.

[flubyu]

Old thread...but I have this same issue. I am in the process of fabbing up the tool as described. Wondering though, why is this a one shot deal? If i don't get it into place on the first try I can't attempt it again?

[EuropeanAM]

You can "attempt" as many times as you like. The problem is that if you don't get the collar properly aligned and try to drive it in, it will BEND in such a fashion that you will likely never get it in place.

Hence the "one shot deal".

[flubyu]

I see, thank you Don!