Help...I can't get lower unit back on 5hp Nissan 4 stroke

[BillP]

The title says it all. I took the lower unit off and changed the water pump with no problems. Now I can't get the splines back in. I've done this with many other engines and never had issues. Is there something special to be done to get the unit back on? I have a manual and it has the same instructions as every other motor. This one has me stumped. I'm to the point of pulling the head off to check the splines...but really don't want to work that hard for what is normally a simple job. This should have been done in an hour! Its a 1999 Nissan 5 hp 4 stroke.

Any info is appreciated.

Bill P

 

[Barnacle_Bill]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

I have been successful by putting upward pressure on the lower unit while someone else turns the flywheel. It usually just takes a fraction of an inch.

 

[chumstain]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

i usually put the lower unit in gear and turn the prop to line up the splines

 

[pvanv]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

It's not unusual to completely miss the bottom of the crank when raising the LU. In which case, the driveshaft will strike alongside the crank, instead of lining up with the splines. Takes a "feel" (and some patience) to make sure you are near the splines. Then maybe a slight revolution of the flywheel to re-engage the splines. If you are really stuck, pop out the 6 bolts that retain the powerhead, insert the LU, and reinstall the powerhead. You may need a new base gasket if you do pull the powerhead.

 

[BillP]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

I've done enough of these on other engines to consider myself experienced...old age must be making me stupid! I know the drive shaft is going into the small tube but it hits something about 3" out...not even close. Rotating the shaft hasn't helped. One more try and the head is coming off. Thanks.
bp

 

[TOHATSU GURU]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

It sounds like you are hitting the crankcase head at the bottom of the block/crank shaft. Like Paul said, it's a feel issue. I've struggled to get many a lower unit back on. Sometimes they go in the first time with no effort. Sometimes you just have to walk away and let ANYONE else do it.

 

[BillP]

Re: Help...I can't get lower unit back on 5hp Nissan 4 stroke

Walkiing away for a day really helped...I wasn't seeing the forest fo the trees! After looking carefully with a flashlight I fouind the hangup was the shift rod not finding it's way into the upper hole. Once I jiggled it around it took about 5 minutes to finish the installation. Lesson learned on the Nissan. Always check that alignment.

Thanks for responding guys, it helped fix my brain drain.

bp