Mercruiser 3.0 Alpha 1 Gen 2 Driveshaft Sticking Out

[Roadblock007]

Recently while underway the boat started making a clicking noise around the top of the upper unit. It changed the tone of the whole outdrive, like a hole in a car exhaust. I suspect it's the universal in the driveshaft. I am at the lake and the clicking continued at random speeds, random times, and random trim/tilt levels. It is now not clicking but sounds rough all the time. I took a good look around and noticed that the driveshaft seems to be pretty far back out of the engine. Is this normal?

 

[Roadblock007]

Don't know if the photos are working.

 

[Bt Doctur]

? ????????????????
the input shaft does enter the coupler that is bolted to the flywheel

 

[Bt Doctur]

 

[Bt Doctur]

If your hearing noises ,its time for drive removal and inspection before something blows apart

 

[Roadblock007]

I'm sorry. Is that a question or a statement? Is it normal to have that much spline showing?

 

[Bt Doctur]

with most of the engines and drives I work on it is, the length is fixed and cannot change

 

[Roadblock007]

Alright thank you. I am very experienced with automotive so I'll pull the drive and inspect the universal.

 

[Bondo]

Alright thank you. I am very experienced with automotive so I'll pull the drive and inspect the universal.

Ayuh,..... I'd drain the drive's oil 1st, 'n look for metal in it,.....

 

[Bt Doctur]

and shift into fwd gear too

 

[harringtondav]

Something is terribly wrong. That shaft is supposed to be much farther ahead 1 -1.5" into the coupler. The O ring is supposed to be inside, sealing the coupler grease. Stop running now and pull the drive. I can't imagine what would allow the driveshaft/U joint assembly to pull back that much, but I bet it will be ugly.

 

[harringtondav]

...ps. It may be possible someone rebuilt the drive shaft/ U joint assy. with the wrong engine coupler U joint shaft, shown by Bt Doctur above. I'm pretty sure various Stern Drives have had different lengths over the years. This is the only expatiation I can think of. Something is too short, and you're only getting partial spline engagement in the coupler. I bet that has caused the alum. splines in the coupler to wear, and finally start fussing.

I just measured my '96 Alpha Gen 2. The distance from the end of the splined shaft to the face of the castle lock ring is exactly 14" The gear end yoke that goes into the upper hsg also comes in different lengths. One of these has to be the wrong length.

 

[Bt Doctur]

can also be from the coupler not having the shroud for greasing

 

[harringtondav]

..also, Merc specifies a transom thickness of 2 - 2.25". If someone got carried away with a transom rebuild, and added an extra inch, the coupler shaft will come up short.

 

[harringtondav]

Bt Doctur It does look like his coupler is an older model w/o the shroud. But I'm still thinking the shaft used in older and newer couplers were different lengths. I just looked up a p/n for the older M/R/MR dirves, and it is different. Roadblock007 what year is your boat, and what is the maintenance history in the O/D gimbal area?

 

[Roadblock007]

Boat is 1991 Bayliner and I have no history of maintenance in that area. IIpulled the lower unit and did new impeller and seals and fluid at the beginning of this season. The gimbal bearing and bellows was on my to-do list for this upcoming off season.

 

[Fun Times]

The distance between the o'ring drive shaft to engine coupler engagement appears normal from what I have seen for certain model applications plus below are some random photos of the same area found online...One boat in the images below had a spun engine coupler while the other had no coupler issues.

https://us.v-cdn.net/5020499/uploads/FileUpload/53/38b3fdcda0b378296370767003c17c.jpg
https://forums.iboats.com/forum/eng...rcruiser-gear-lube-leak?p=9926111#post9926111

 

[Fun Times]

Boat is 1991 Bayliner and I have no history of maintenance in that area. IIpulled the lower unit and did new impeller and seals and fluid at the beginning of this season. The gimbal bearing and bellows was on my to-do list for this upcoming off season.

Please know that the post above isn't to deter you from fully inspecting things out which needs to happen to help sort out the sounds you're hearing though as damage in that same area is still possible and can't be found unless pulled apart, etc., etc..

Keep us updated, good luck.