Alpha One Gen2 Grinding Noise at extreme turns

[fender147]

Last summer my 2008 Starcraft w/ Mercruiser Alpha One Gen2 I/O started making loud grinding noise at high trim and during turns. The problem was pretty obviously the u joints so I replaced them (Sierra U-Joint-Mc #865496A02) which made a big improvement, although they were very difficult to get in the yoke and coupler. However, a less severe noise persists at and near the turning extremes and also when trimmed up all the way (straight and turns). Next I replaced the gimbal bearing (although the old one moved freely) but the grinding noise persists, as seen in the video below.

In this video, disregard the engine "ticking" and notice the grinding noise come as go as we progress through the turning range. The noise only happens when in gear, either fwd or rev. In neutral, there is no noise throughout the turning or trim range.

I plan to check the u joints again to make sure they still move freely (they did when they were replaced the first time though). Any advice on what else could be causing this would be appreciated.

 

[kghost]

This is NORMAL when trimmed all the way up as it puts a strain on ujoints and gimbal bearing. It is not reccomened to do this but for only temporary while in shallow water. Not as a normal method of propulsion......

 

[fender147]

This is NORMAL when trimmed all the way up as it puts a strain on ujoints and gimbal bearing. It is not reccomened to do this but for only temporary while in shallow water. Not as a normal method of propulsion......

Thanks, the video is trimmed fully down where the noise also happens at the turn extremes. I just wanted to mention the noise happens when trimmed up as well.

 

[kghost]

When you installed new gimbal bearing, did you check alignment of bearing to coupler? Was removing and installing drive easy or difficult meaning you had to force it?

 

[fender147]

Used an alignment tool to set the new bearing before installing the drive. The drive came off easy but was challenging getting it back in. Had to carefully tap it in to get it started.

 

[kghost]

You have bigger problems based on the noise from that video. whats that loud ticking?

When you installed the gimbal bearing, how did you do this? Are you sure it is seated all the way? Did you replace the two orings on the drive shaft? they keep the shaft in "suspension" within the gimbal bearing. If this does not occur the the shaft will be rubbing on the gimbal inner bearing race.

When drive is away/off from the gimbal housing is there any signs of metal flake?

When was the gear oil for outdrive changed last and what did it look like?

 

[fender147]

The engine ticking has been there for a couple years now, no performance issues. I think it's an exhaust leak, will investigate that next.

I used this bearing install tool. I'm confident that the bearing is seated all the way because I could not feel any gap after install. I'm pretty sure I reused the o rings on the drive shaft as they looked to be in good condition but I'll replace them next time its apart. Will check for any signs of rubbing on the shaft too.

No signs of metal flake in the gimbal housing and I change the gear oil regularly (done at the beginning last season), any flakes were minimal.

I can't help but focus on the u joints again since the noise only happens at the turning extremes (the rest of the gears spin regardless of the turn angle.)

 

[kghost]

At this point without physically being able to her and see your issue, I would suggest taking the top cap off the outdrive and carefully inspect the cap bearing. Look for discoloration or the needles in the tapered bearing to be discolored or severly pitted. Then rotate the ujoint assembly and listen and feel very carefully for the two back to back tapered bearings in the snout (where the Ujoint yoke goes into) to see if you may have bearing failure. maybe it will have a slight grumbling sound vs no sound

If at some time the drive was run to low on gear oil or water got in due to a seal leak and was not fixed in a timely manner or the drive sat unused for many years, the bearings could have become pitted and could cause the noise.

 

[kghost]

"""I used this bearing install tool. I'm confident that the bearing is seated all the way because I could not feel any gap after install."""

That is not how it is checked. You cannot see or really feel this.

My experience in installing the gimbal bearing (and I have done hundreds) is,

Using a driver tool (similar to the pics you showed but I designed my own) but use the same method with NO plastic or wood between the 3 pound sledge hammer and the steel driver rod. You pound the bearing in until you clearly hear a tone change for two consecutive hits signalling the bearing has bottomed out in the pocket. This may not be as easy to detect if you only do one but it is a very different tone.

 

[Dieter]

"""I used this bearing install tool. I'm confident that the bearing is seated all the way because I could not feel any gap after install."""

That is not how it is checked. You cannot see or really feel this.

My experience in installing the gimbal bearing (and I have done hundreds) is,

Using a driver tool (similar to the pics you showed but I designed my own) but use the same method with NO plastic or wood between the 3 pound sledge hammer and the steel driver rod. You pound the bearing in until you clearly hear a tone change for two consecutive hits signalling the bearing has bottomed out in the pocket. This may not be as easy to detect if you only do one but it is a very different tone.

would add to this its easy to cock the bearing and think it is seated. As Jack outlines you can hit the outer race with a drift etc with out fear of damaging the bearing and use a BFH to hit it home

 

[fender147]

At this point without physically being able to her and see your issue, I would suggest taking the top cap off the outdrive and carefully inspect the cap bearing. Look for discoloration or the needles in the tapered bearing to be discolored or severly pitted. Then rotate the ujoint assembly and listen and feel very carefully for the two back to back tapered bearings in the snout (where the Ujoint yoke goes into) to see if you may have bearing failure. maybe it will have a slight grumbling sound vs no sound

If at some time the drive was run to low on gear oil or water got in due to a seal leak and was not fixed in a timely manner or the drive sat unused for many years, the bearings could have become pitted and could cause the noise.

Thanks, I'll follow these instructions next time its apart. Any thoughts about an engine coupler issue like worn splines? Hard to see but maybe I can reach in to feel them?

 

[fender147]

would add to this its easy to cock the bearing and think it is seated. As Jack outlines you can hit the outer race with a drift etc with out fear of damaging the bearing and use a BFH to hit it home

Thanks, maybe I'll give it a few more hits for good measure next time its apart.

 

[kghost]

Thanks, I'll follow these instructions next time its apart. Any thoughts about an engine coupler issue like worn splines? Hard to see but maybe I can reach in to feel them?

The only way to determine coupler condition while engine is in the boat is the presence of aluminum material on the drive shaft splines. The drive shaft splines are steel, the female splines of the coupler are aluminum. If un-lubricated for long periods or out of alignment the female splines of the coupler will wear badly or even strip out which would STOP turning the drive shaft and engine would over heat as no water would be pulled in through impeller in the outdrive.

One of the short comings of the Gen II design is the newer couplers and driveshafts (with three orings) The coupler has grease fittings to grease the splines and the third oring on drive shaft is to keep the grease in the coupler. Problem is no one can reach the grease fitting(s) on the coupler so it never gets greased. With the use of non serviceable ujoints and gimbal bearing the drive is no longer removed annually to grease ujoints and drive shaft splines and replace and grease the orings and inspect gimbal bearing. This in my opinion leads to a lot of unsuspected problems.

Thus When ever I service a Gen II I still pull the drive annually and do what I can like grease the shaft by hand, Replace all orings and grease them liberally, check gimbal bearing spin by feel ect.

You as a boat owner doing your own maintenance is good but until you understand all the things to do, how to do them and why, You are possibly not going to do every thing correctly or at all. Best to ask here first for opinions and not wait for problems to surface.

JMHO............

 

[fender147]

Just to follow up for anyone else dealing with these symptoms, the problem was the u joints after all. After buying the proper parts and replacing both u joints (again) the grinding went away. Lesson learned: pony up for quality parts. Also, the engine ticking in the video was leaky exhaust and manifold/flaps replaced took care of it.

 

[Dieter]

Just to follow up for anyone else dealing with these symptoms, the problem was the u joints after all. After buying the proper parts and replacing both u joints (again) the grinding went away. Lesson learned: pony up for quality parts. Also, the engine ticking in the video was leaky exhaust and manifold/flaps replaced took care of it.

thanks for following up - when you say quality parts do you mind sharing the brand of cheap u joint that made the noise (was that sierra?) and what parts you put in?

 

[fender147]

Good question, the part that didn't work was Sierra brand which was half the price of Merc/Quicksilver part. 865496A02

 

[Dieter]

Good question, the part that didn't work was Sierra brand which was half the price of Merc/Quicksilver part. 865496A02

yeah the Mercs are like $270 each . I used spicer equivalents two years ago, I have some vibration but I think my alignment is off, so I need to pull my drive and check. Getting weird shudder when I trim in under load. I was asking as I was thinking if the ujoints didnt hold up I would use OEM.

Issue with the perma lube ones is they only lasted about 300 -350 hrs on mine vs the 23 yr old greaseable ones on my old boat (gen 1) ...

Anyone have good results with the any aftermarket greaseable gimbal bearings? I should have left my original one in as the bellows never leaked, was chasing a vibration did the perma lube bearing got through last season ok, but forgot to align it after seemed ok, but have vibration this year...

I wonder if you can take a perma lube bearing apart and drill it for the lube port? I think they are SKF bearings which are great quality