Alpha 1 Gen 2 Lower unit removal

[Simoniz]

Hi Im trying to separate the lower unit from the upper unit on my Alpha 1 Gen 2 Outdrive, S/N OL 634881 in order to renew the impeller.

Ihave removed all 6 bolts and the lower drive has separated from the upper by about 1/4 inch, such that the dowels have disengaged but the lower unit wont come off any further. The Shifter is in Fwd gear and I have separated this drive before so I know it will come apart.

In the gap that is there, I can see quite a lot of crud, so is it that thats holding it together, or is there some other step that Ive forgotten? I dont really want to use excess force in case I break something or bend the driveshaft.

 

[achris]

Re: Alpha 1 Gen 2 Lower unit removal

You won't bend the drive shaft. All I can think is the dowels are still engaged and hanging up. Is the 1/4" gap all the way around, or just at one end?

Chris....

 

[Simoniz]

Re: Alpha 1 Gen 2 Lower unit removal

Hi Thanks for answering.

1/4inch gap is all around and the lower unit is definitely not hanging on the dowels, both ends are free. Just seems to be stuck either on the drive shaft or the water pipe connection. MAybe Ill rig up some kind of puller then and wind it off in a controlled manner.

 

[BigDog98]

Re: Alpha 1 Gen 2 Lower unit removal

This is very weird. If you have quit a bit of corrosion on there then it may be the reason. Try and stick a crowbar in the gap and try and lift it up If there is no budge then stop. You could also try and put some penetration oil in there to see it it helps. Remember 4 bolts on the sides of the drive and 1 underneath the trim zinc and 1 next to the shift shaft hook up.

 

[81 Checkmate]

Re: Alpha 1 Gen 2 Lower unit removal

Did ya get the bolt under the zinc........Ive done the same thing it will drop about a 1/4" then thats it.

Good Luck!

 

[Simoniz]

Re: Alpha 1 Gen 2 Lower unit removal

Well Ive removed 6 bolts in total, the obvious 4 at the sides, one under the round anode / trim tab and one at the front. Are there any more?

 

[Bt Doctur]

Re: Alpha 1 Gen 2 Lower unit removal

Did this unit have a severe impact at any time? This pic if from a prop shaft but I have seen the same twist in lower unit driveshafts. This causes the shaft to jam in the upper unit.

 

[achris]

Re: Alpha 1 Gen 2 Lower unit removal

Well Ive removed 6 bolts in total, the obvious 4 at the sides, one under the round anode / trim tab and one at the front. Are there any more?

No, you got them all. As already mentioned, could be just the 'O' rings in the water tube tying you up... I would use a SMALL lever at this stage, nothing like a crowbar, maybe a screwdriver...

 

[Simoniz]

Re: Alpha 1 Gen 2 Lower unit removal

Thanks for the advice, tried again this morning and jacked the lower unit off with some bolts between the vanes on the anti vent plates. It actually came apart easily with very little force and it was just the crud and the o rings on the drive shaft and water tube that was holding it together.

 

[Simoniz]

Impellor replacement - should I replace the 2 top seals as well?

Impellor replacement - should I replace the 2 top seals as well?

Ive got my Alpha 1 Gen 2 lower unit of to replace the impeller. Now that Ive got it apart so far, should I replace the plastic seal carrier together with the 2 oil seals and O ring, which sit on top of the drive shaft below the impeller (items 18, 19, 20 & 21 on Merc Service Manual No 14, Standar Rotation Gear Housing Exploded Parts View)?

I realise that its probably a good idea to do so but the plastic seal carrier looks like it might be difficult to prise out - any tips for doing so?

 

[Simoniz]

Drive shaft o ring remained in upper unit.

Drive shaft o ring remained in upper unit.

So Ive removed my lower unit (Alpha 1 Gen 2) and the o ring which sits at the top of the drive shaft seems to have remained between the upper drive shaft seals, ie it has not stayed on the top of the drive shaft.

Ive looked at the pdf entitled "Replacing a Mercruiser Raw Water Pump Impellor" from the Stickys section and the section entitled, "Gear Housing Disassembly", these is a note which says, "If O ring remains lodged between upper drive shaft seals (in drive shaft housing), be sure to remove O ring or reassembly will be impaired"

The o ring looks as if it is in a groove in the upper housing, so cant I just put it back together as it is? I would have thought that if I remove the o ring and put it on the shaft, then when I insert the drive shaft back up into the upper housing, the oil seals will simply push the o ring back down the shaft and it wont end up in the correct position.

If not, please are there any tips on how to remove the o ring and where to position it on the drive shaft when I put it back together?

 

[achris]

Re: Drive shaft o ring remained in upper unit.

Re: Drive shaft o ring remained in upper unit.

Alpha One Gen II never had an 'O' ring on the top of the lower drive shaft... Are you sure you're working on a gen II? Can you provide a drive serial number?

Chris......

 

[achris]

Re: Impellor replacement - should I replace the 2 top seals as well?

Re: Impellor replacement - should I replace the 2 top seals as well?

If the seals are leaking or the plastic housing distorted, or it failed a pressure test at that location, replace it, if not, leave it alone.

 

[achris]

Re: Alpha 1 Gen 2 Lower unit removal

.... my Alpha 1 Gen 2 Outdrive, S/N 0L634881 ....

BTW, that serial number is for a 3.0L engine, not a drive...

 

[Simoniz]

Re: Drive shaft o ring remained in upper unit.

Re: Drive shaft o ring remained in upper unit.

Alpha One Gen II never had an 'O' ring on the top of the lower drive shaft... Are you sure you're working on a gen II? Can you provide a drive serial number?

Chris......

Oh, OK, in that case all is in order, as no o ring came out with the drive shaft. Yes, its definitely a gen II, Transom SN is OL828972, boat is a year 1999 manufacture. I know I posted the engine SN, but it the teansom SN does not cover the drive as well, then I dont know what the SN of the drive is.

Thanks to for the advice about the seals. Ill block off the oil gallery and pressure test the lower unit then and if all is in order, leave the seals alone.

Mods - I see you have put the three threads together. Sorry for starting new ones, I thought it was best to do so as the new topics didnt seem to have much to do with the removal of the lower unit, but I guess its the same job.

Cheers!