Bravo Rattle - Alignment Woes
06-06-2016, 03:19 PM
#1
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Bravo Rattle - Alignment Woes
Having a major issue with alignment on my Formula, and I'm trying some ways to get it figured out.
My issue started out like this:
I aligned the engine at installation back last summer, then the boat sat until I really started working on it in the fall. I never really trusted the alignment, but thought I had it really really close. The drive slips in easily, every time I've had it off (a few times now). The issue is noise. It sounds like I have a series of marbles bouncing around in the top of the drive. I've changed the fluid (perfect when it came out), and I've had the top cap and rear plate off the drive (gears are perfect, and everything looks good), I've greased the gimbal bearing, and replaced the u-joints; the rattle remains AND can be heard above the exhaust (granted, I have the Silent Thunder box on it, but the risers got to the tips, water is draining at the transom, and the baffles are pounded out). While doing some troubleshooting, I noticed that if the drive was really low, trim-wise, the noise was lessened by a good amount. Also, if I move the drive left and right, the noise increases substantially. That tells me that the u-joints and coupler are out of phase. Sound right?
This weekend, I decided to dive into it. I broke out my trustee Blue Point angle finder, leveled the trailer so that the keel was at zero degrees, measured the angle of the transom (found it to be at 15 degrees), then measured the engine (multiple places... blower pulley, crank pulley, flame arrestor), and found that I was about eight degrees off (high in the front... unsure of how the drive went on but it did). My problem now is that I have no more adjustment left in the mounts; I'm bottomed out. The friend that did my transom and stringer work ended up being a bit high on the mounting pad placement.
I'm thinking about duplicating IMCO's offshore mount (it's pretty much what Formula set-up in the first place except they used a Merc rubber mount versus solid). I was going to remove the rubber mount, and go with a solid 3/4 x 3-inch fine thread Grade 8 bolt with jam nuts, etc. to make my own so I think I have the solution figured out, but just wanted to run this by the collective for any thoughts, suggestions, etc. This is THE last thing left to do to really start enjoying this thing.
Outside of the alignment issue, I plan to change out the gimbal bearing (it feels great, but I want to eliminate any other possibilities with regard to the noise), and recheck the alignment with the tool once I have the mount issues worked out. I know finding the installed angle will get me close.
Anyway, open to comments and suggestions.
Thanks!
My issue started out like this:
I aligned the engine at installation back last summer, then the boat sat until I really started working on it in the fall. I never really trusted the alignment, but thought I had it really really close. The drive slips in easily, every time I've had it off (a few times now). The issue is noise. It sounds like I have a series of marbles bouncing around in the top of the drive. I've changed the fluid (perfect when it came out), and I've had the top cap and rear plate off the drive (gears are perfect, and everything looks good), I've greased the gimbal bearing, and replaced the u-joints; the rattle remains AND can be heard above the exhaust (granted, I have the Silent Thunder box on it, but the risers got to the tips, water is draining at the transom, and the baffles are pounded out). While doing some troubleshooting, I noticed that if the drive was really low, trim-wise, the noise was lessened by a good amount. Also, if I move the drive left and right, the noise increases substantially. That tells me that the u-joints and coupler are out of phase. Sound right?
This weekend, I decided to dive into it. I broke out my trustee Blue Point angle finder, leveled the trailer so that the keel was at zero degrees, measured the angle of the transom (found it to be at 15 degrees), then measured the engine (multiple places... blower pulley, crank pulley, flame arrestor), and found that I was about eight degrees off (high in the front... unsure of how the drive went on but it did). My problem now is that I have no more adjustment left in the mounts; I'm bottomed out. The friend that did my transom and stringer work ended up being a bit high on the mounting pad placement.
I'm thinking about duplicating IMCO's offshore mount (it's pretty much what Formula set-up in the first place except they used a Merc rubber mount versus solid). I was going to remove the rubber mount, and go with a solid 3/4 x 3-inch fine thread Grade 8 bolt with jam nuts, etc. to make my own so I think I have the solution figured out, but just wanted to run this by the collective for any thoughts, suggestions, etc. This is THE last thing left to do to really start enjoying this thing.
Outside of the alignment issue, I plan to change out the gimbal bearing (it feels great, but I want to eliminate any other possibilities with regard to the noise), and recheck the alignment with the tool once I have the mount issues worked out. I know finding the installed angle will get me close.
Anyway, open to comments and suggestions.
Thanks!
06-06-2016, 05:00 PM
#2
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iTrader: (7)
Only noise I've ever had like that on a bravo was after I grenaded it or the gimbals bearing went out. Btw your not running engines with drives all the way up in trailer position are you? Can you use offshore mounts?
06-06-2016, 05:38 PM
#4
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Tom, angle finder is a good idea but don't over complicate it.
A mercury gimbal housing is made for a 13 degree transom angle. So with a 15 you would expect the engine to be 2 up in the front.
Just use the Mercury alignment tool and see where you are. Check the rear mount hardware stack up. Actually see what the gimbal bearing feels like. Put some pressure on it while you turn it. If you feel any roughness at all replace it.
A mercury gimbal housing is made for a 13 degree transom angle. So with a 15 you would expect the engine to be 2 up in the front.
Just use the Mercury alignment tool and see where you are. Check the rear mount hardware stack up. Actually see what the gimbal bearing feels like. Put some pressure on it while you turn it. If you feel any roughness at all replace it.
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Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
06-06-2016, 06:10 PM
#5
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The mount that I'm referring to is this from IMCO (sorry, was in the "offshore mount" section of their site):
http://www.cpperformance.com/p-13831...kit-black.aspx
it is very similar to how Formula originally mounted the engine just without the rubber pieces.
06-06-2016, 06:20 PM
#7
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Tom, angle finder is a good idea but don't over complicate it.
A mercury gimbal housing is made for a 13 degree transom angle. So with a 15 you would expect the engine to be 2 up in the front.
Just use the Mercury alignment tool and see where you are. Check the rear mount hardware stack up. Actually see what the gimbal bearing feels like. Put some pressure on it while you turn it. If you feel any roughness at all replace it.
A mercury gimbal housing is made for a 13 degree transom angle. So with a 15 you would expect the engine to be 2 up in the front.
Just use the Mercury alignment tool and see where you are. Check the rear mount hardware stack up. Actually see what the gimbal bearing feels like. Put some pressure on it while you turn it. If you feel any roughness at all replace it.
Gimbal bearing... I've turned the bearing and it felt very smooth, but I'm not so sure of it so I'm going to replace it anyway. I've got all of the service records for the boat since she was built... the bearing has never been replaced. Now's a good time.
06-06-2016, 06:31 PM
#8
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U Joints and or GB also another thing to throw out - warped coupler or loose couple bolts or even one that fell out and is rolling around.
IMO my best guess here, I would look into the coupler and or is bolts / nuts loose or one has fallen out rolling around with engine rotation. The odds for the money best guess here is ???
A proper feel and greased GB had a nice smooth roll with two finger rotation but does have drag to it without any play ZERO . Its kind of has a tight smooth drag roll to it. They do not spin freely or roll, Kind of hard to describe in words only.
IMO my best guess here, I would look into the coupler and or is bolts / nuts loose or one has fallen out rolling around with engine rotation. The odds for the money best guess here is ???
A proper feel and greased GB had a nice smooth roll with two finger rotation but does have drag to it without any play ZERO . Its kind of has a tight smooth drag roll to it. They do not spin freely or roll, Kind of hard to describe in words only.
Last edited by BUP; 06-06-2016 at 06:35 PM.
06-06-2016, 07:47 PM
#9
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Platinum MemberThread Starter
iTrader: (2)
U Joints and or GB also another thing to throw out - warped coupler or loose couple bolts or even one that fell out and is rolling around.
IMO my best guess here, I would look into the coupler and or is bolts / nuts loose or one has fallen out rolling around with engine rotation. The odds for the money best guess here is ???
A proper feel and greased GB had a nice smooth roll with two finger rotation but does have drag to it without any play ZERO . Its kind of has a tight smooth drag roll to it. They do not spin freely or roll, Kind of hard to describe in words only.
IMO my best guess here, I would look into the coupler and or is bolts / nuts loose or one has fallen out rolling around with engine rotation. The odds for the money best guess here is ???
A proper feel and greased GB had a nice smooth roll with two finger rotation but does have drag to it without any play ZERO . Its kind of has a tight smooth drag roll to it. They do not spin freely or roll, Kind of hard to describe in words only.
Ujoints are new, and I know for a fact that nothing came off the coupler/flywheel. Red locktite and torqued to spec. The fact that I can move things around and hear/feel the change points to alignment and gimbal bearing. Got the bearing, need to figure out the mounting. The Merc mounts (because of how my guy installed the pads) will not allow me the adjustment needed.
