Banging, clunking and thumping. Driveline problem 496/Bravo
12-05-2017, 01:28 PM
#41
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Platinum Member
BE CERTAIN that they check and correct engine alignment before they put that drive back on there. It's a bit hard to "check" the coupler, but ensuring engine alignment is going to be paramount, especially after your boat spent all that time on it's side on the trip over. I would be CERTAIN to make sure that all of the engine mounting points are sound, and all fasteners are tight. I have seen gimbal bearings go bad before making noise and the like, but I have NEVER seen one come apart.
Have the techs SHOW you their alignment tool and show you how they use it. If they can't do that, you need to find someone that HAS the tool, and knows what they are doing.
Have the techs SHOW you their alignment tool and show you how they use it. If they can't do that, you need to find someone that HAS the tool, and knows what they are doing.
When I originally stated that I was going in the direction of the U joints I had never seen a Gimbal bearing do that before .
12-05-2017, 01:37 PM
#43
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Platinum Member
12-05-2017, 01:53 PM
#45
VIP Member
Remember, this is how rr's boat was shipped over to Asia. The boat was on it's sides for weeks; along with the jarring of loading and shipping.
I would make absolutely certain that the engine mounts are sound.
Other pictures and info he posted leads one to believe the boat had a rough bout on the way over.
Donzi 27 ZR arrives in Thailand
I would make absolutely certain that the engine mounts are sound.
Other pictures and info he posted leads one to believe the boat had a rough bout on the way over.
Donzi 27 ZR arrives in Thailand
12-05-2017, 03:51 PM
#46
Banned
iTrader: (9)
there is not one spec of grease on the GB ball bearings as well. They are pitted and scared and black corrosion badly. the pitting and scaring is no grease and corrosion damage. Water washed out whatever grease was left. The GB never got greased nor did the splines for the engine coupler. Lack maintenance all the way around. they other cause for GB wear and or coming apart is the wrong GB was installed. There is different versions of GB to be installed per what u joints and input shaft is used in the upper. GKN shaft and GKN u joints uses a different GB that the past NLA set up thru Merc . The old set up was Metitor components === (spelling ) I have no idea how to spell the past set up.
If the drive pulled off like butter then more times than not the alignment is good. If it was very hard to pull away the drive - alignment could be the issue as well. Just saying for a laymans term about alignment. Not set in stone. Yes alignment can be the issue but IMO the coupler would have been really worn out and it would have pointed teeth for the coupler splines. I would change the coupler as well here.
If the drive pulled off like butter then more times than not the alignment is good. If it was very hard to pull away the drive - alignment could be the issue as well. Just saying for a laymans term about alignment. Not set in stone. Yes alignment can be the issue but IMO the coupler would have been really worn out and it would have pointed teeth for the coupler splines. I would change the coupler as well here.
Last edited by BUP; 12-05-2017 at 03:53 PM.
12-05-2017, 04:06 PM
#47
https://www.offshoreonly.com/forums/...autosales.html
Mike aka M&RAutoSales here on OSO had a problem with one of the 496HOs in his 35 Fountain where the mounting 'post' (sorry, using bad terms) pulled out of the stringer, and allowed the motor to lift and twist against the drive with the torque of the motor. Given what he told me about this and this only happened over typical operating conditions, I could see this happening with a boat that was stored on it's side like yours was for the shipment/trip.
Mike aka M&RAutoSales here on OSO had a problem with one of the 496HOs in his 35 Fountain where the mounting 'post' (sorry, using bad terms) pulled out of the stringer, and allowed the motor to lift and twist against the drive with the torque of the motor. Given what he told me about this and this only happened over typical operating conditions, I could see this happening with a boat that was stored on it's side like yours was for the shipment/trip.
12-05-2017, 10:31 PM
#48
Gold Member
Gold MemberThread Starter
Great replies as always. I know a lot of you are very busy workwise and you still take the time to post knowledgeable and sensible opinions. Thank you 
A couple of points....
There's only one dealer over here (2 locations). They send technicians to Cambodia frequently to do work for customers so I think they're pretty good.
If you collected all the sports boats in Thailand at one location, they'd fit in the car park at Walmart.
I speak a bit of Thai but I don't know the Thai for technical words and 'Mercury specific' words like coupler, gimbal, alignment etc so there is a language barrier.
The boat has not been mistreated but I suspect it hasn't been serviced properly given the low hours but it's still 10 years old. It was a fresh water boat. It gets flushed after every use here, on the ramp, when they pull her out. The last time out it ran flawlessly, about 8 weeks prior.
My guess now, the bellows split towards the end of the previous day out and the salt water came in and started doing its damage. The engine was flushed and the damaged bearing sat in fresh water for 6 weeks. Put her in the water this time with split bellows and it quickly flushed all the grease out and then the bearing collapsed completely. The engine was flushed and she was put away. The water you see inside is fresh water, I tasted it to make sure. Yuk!
The technicians say the coupler should be good. The drive is now in their workshop to check it out properly. I will go and have a look when they contact me with an update.
There is no visible sign of stringer damage around the engine mounts and I'll be poking my hand around inside to feel the coupler splines and anything else I can find. I will ask the technicians to double check the coupler and the engine alignment.
Fingers crossed and thanks again for the advice, it's been a HUGE help. (Oops, capitals...)
RR
A couple of points....
There's only one dealer over here (2 locations). They send technicians to Cambodia frequently to do work for customers so I think they're pretty good.
If you collected all the sports boats in Thailand at one location, they'd fit in the car park at Walmart.
I speak a bit of Thai but I don't know the Thai for technical words and 'Mercury specific' words like coupler, gimbal, alignment etc so there is a language barrier.
The boat has not been mistreated but I suspect it hasn't been serviced properly given the low hours but it's still 10 years old. It was a fresh water boat. It gets flushed after every use here, on the ramp, when they pull her out. The last time out it ran flawlessly, about 8 weeks prior.
My guess now, the bellows split towards the end of the previous day out and the salt water came in and started doing its damage. The engine was flushed and the damaged bearing sat in fresh water for 6 weeks. Put her in the water this time with split bellows and it quickly flushed all the grease out and then the bearing collapsed completely. The engine was flushed and she was put away. The water you see inside is fresh water, I tasted it to make sure. Yuk!
The technicians say the coupler should be good. The drive is now in their workshop to check it out properly. I will go and have a look when they contact me with an update.
There is no visible sign of stringer damage around the engine mounts and I'll be poking my hand around inside to feel the coupler splines and anything else I can find. I will ask the technicians to double check the coupler and the engine alignment.
Fingers crossed and thanks again for the advice, it's been a HUGE help. (Oops, capitals...)
RR
Last edited by rak rua; 12-06-2017 at 12:59 AM.
12-06-2017, 06:33 AM
#49
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there is not one spec of grease on the GB ball bearings as well. They are pitted and scared and black corrosion badly. the pitting and scaring is no grease and corrosion damage. Water washed out whatever grease was left. The GB never got greased nor did the splines for the engine coupler. Lack maintenance all the way around. they other cause for GB wear and or coming apart is the wrong GB was installed. There is different versions of GB to be installed per what u joints and input shaft is used in the upper. GKN shaft and GKN u joints uses a different GB that the past NLA set up thru Merc . The old set up was Metitor components === (spelling ) I have no idea how to spell the past set up.
If the drive pulled off like butter then more times than not the alignment is good. If it was very hard to pull away the drive - alignment could be the issue as well. Just saying for a laymans term about alignment. Not set in stone. Yes alignment can be the issue but IMO the coupler would have been really worn out and it would have pointed teeth for the coupler splines. I would change the coupler as well here.
If the drive pulled off like butter then more times than not the alignment is good. If it was very hard to pull away the drive - alignment could be the issue as well. Just saying for a laymans term about alignment. Not set in stone. Yes alignment can be the issue but IMO the coupler would have been really worn out and it would have pointed teeth for the coupler splines. I would change the coupler as well here.
Bup, surely the drive will always come out easily with no gimble bearing left ( unless the splines are corroded)?
12-06-2017, 06:54 AM
#50
Registered
If the front of the engine has dropped down due to the front mount lower nuts backing off it will pinch the input shaft in the coupler and can be all but impossible to remove the drive. Have had that happen to me on a previous boat. Drive would not come off until I lifted the front of the engine back up. It doesn't take much movement either to pinch the drive in place.
