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Have a Merc Bravo 3.  When I flush the engine is the drive supposed to be trimmed up or down? I saw a Merc video that says trim it up.

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I dont think Mercruiser would put out a video showing that. Dont believe everything you find on the net

Down is best

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I can't believe it would matter.  When I flush mine (rarely), it's after I've pulled it from the water, it's on the trailer, and the drive is up.  The drive is always up when on the trailer unless maintenance requires otherwise (fluid changes, removal, etc.)

 

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When the trim is up you are putting excess strain on the U joints of the drive. Even with the drive in neutral the drive is still under torque when the engine is running. Always run in down position if possible.

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2 hours ago, Chap243 said:

When the trim is up you are putting excess strain on the U joints of the drive. Even with the drive in neutral the drive is still under torque when the engine is running. Always run in down position if possible.

When I am flushing it's because I've just pulled it from saltwater and plan to drive hundreds of miles that day.  Drive stays up.

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33 minutes ago, TexasPilot71 said:

When I am flushing it's because I've just pulled it from saltwater and plan to drive hundreds of miles that day.  Drive stays up.

It's best not to have the drive in the full up/out trailer position when the engine is running as this position places the u-joints at an extreme angle.  I have seen the tabs on the retainer nut ground half down from running with the drive in the trailer position.

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I always leave any drive as close to straight down as possible.  Trailering with a skeg dragger is different. If you do not or can not trust the hydraulics for a trip ?  Cut a 2 X 4 and wedge it in place after tilting the drive up enough to feel safe. You might need a wider board on some motors. 2 screw eyes into the board with a stretch cord does it.

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Yes, crank them ALL the way up till the hyd pump groans, I make more money that.way. A new gimbal housing and a new drive after the U joints explode

DSCN2492.jpg

Now if you want to keep some of that money , lower the drive to flush and raise it to trailer.

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1 hour ago, cyclops2 said:

I always leave any drive as close to straight down as possible.  Trailering with a skeg dragger is different. If you do not or can not trust the hydraulics for a trip ?  Cut a 2 X 4 and wedge it in place after tilting the drive up enough to feel safe. You might need a wider board on some motors. 2 screw eyes into the board with a stretch cord does it.

I will stick with these.....

SIE-18-9098_lg__49806.1469113196.1280.12

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On 8/10/2018 at 5:44 PM, Dennis A said:

It's best not to have the drive in the full up/out trailer position when the engine is running as this position places the u-joints at an extreme angle.  I have seen the tabs on the retainer nut ground half down from running with the drive in the trailer position.

Good to know and lesson learned!  I've only done it this way twice...both times pulling out of Florida.  And after that second trip this past June, I replaced the entire shaft, U-joint, gimbal, and everything associated.  So I got all new stuff!

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On 8/10/2018 at 6:02 PM, TexasPilot71 said:

When I am flushing it's because I've just pulled it from saltwater and plan to drive hundreds of miles that day.  Drive stays up.

I understand. I was referring to flushing the engine while running engine with the drive up.

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On ‎8‎/‎10‎/‎2018 at 10:00 PM, Bt Doctur said:

Yes, crank them ALL the way up till the hyd pump groans, I make more money that.way. A new gimbal housing and a new drive after the U joints explode

DSCN2492.jpg

Now if you want to keep some of that money , lower the drive to flush and raise it to trailer.

Hahaaa, nice!  Hey, lemme ask you a question - before mounting the gimbal housing back on the transom and bolting it, do you add 4200 to the rubber seal that goes all the way around the housing or not?  I'm helping a friend put his Alpha back on and he wants to put a bead of 4200 just outside the edge of that rubber sealer before remounting it and I was telling him we should check to see if it's ok to do.  I've seen others do it and I know it's ultimately a much better seal on top of the rubber, but does it affect the rubber?  Or the way the housing sits on the transom with the added thickness of the goo?

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No , I use 3M  Weatherstrip adhesive on the rubber gasket , once the gasket is installed a very SMALL bit of black RTV between the gasket edge and housing edge

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2 hours ago, Bt Doctur said:

No , I use 3M  Weatherstrip adhesive on the rubber gasket , once the gasket is installed a very SMALL bit of black RTV between the gasket edge and housing edge

Ah, ok.  Good to know, thanks.  We're using a gasket sealer but he wanted to add an additional bead of something as a secondary sealer between the housing and the transom. 

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On 8/10/2018 at 5:44 PM, Dennis A said:

It's best not to have the drive in the full up/out trailer position when the engine is running as this position places the u-joints at an extreme angle.  I have seen the tabs on the retainer nut ground half down from running with the drive in the trailer position.

Actually, hang on...if the engine is running but the drive is not in gear, how would anything in there grind down?  

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18 hours ago, Chap243 said:

I understand. I was referring to flushing the engine while running engine with the drive up.

Oh yes, so was I. Flushing with muffs. 

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because on a Alpha drive , Bravo cobra drive, volvo drive the U joints are spinning with the motor running

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15 minutes ago, TexasPilot71 said:

Actually, hang on...if the engine is running but the drive is not in gear, how would anything in there grind down?  

Gear change is done in the bottom of the outdrive. Everything inside the top is always spinning.

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That's the reason I trim all the way Down BEFORE I start up. In the summer, my boat lives on a lift, well out of Lake Huron. I usually like to trim Up into the trailer zone - keeping the outdrive from taking hits from any wave action. When we're ready to take her out,  I lower her down almost, but not, free floating off the lift. I then trim the outdrive Down fully which keeps the u-joints from working at much of an angle. Once she's running, and warmed up, we get aboard and lower the lift the rest of the way to float off.

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5 hours ago, TexasPilot71 said:

Actually, hang on...if the engine is running but the drive is not in gear, how would anything in there grind down?  

Everything is spinning... just not in gear..... parts is parts. ..spinning is spinning. Think outside the props... everything on top of the leg is spinning... trust us.... trim down when the engine is running... 

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The outdrive input shaft slips into the engine flywheel coupler so as others have said, if the engine is running, the top bearing and gear set are turning. The shift mechanism on a Volvo Dual Prop or Bravo drive is in the upper gearcase of the out drive. On a Alpha drive it's a dog clutch in the foot, just ahead of the propeller.

We beat this to death but as the manual states, running the engine with the drive in or near the full up position is not recommended, and should be reserved for idle only operations in very shallow waters. The angle is not the issue, again as stated in the manual. The constant velocity dual u-joints could care less, and the gimbel bearing is slip fit designed to compensate, and the engine couple is a lubricated spline, which also could care less what the drive angle is. The problem is that as the drive reaches the upper limits of trim up, the side "ears" exit the gimbel ring and looses the required side support for high torque operation. Idling into a beach with the drive 80% up is not an issue, but if you were to hit something at that moment, severe damage is much more likely. Storing a drive in the full up induces strain to the drive shaft bellows as they take a set over time and are more likely to fail when returned to service. Again the other mechanical's could care less.  W

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13 hours ago, Phillbo said:

Everything is spinning... just not in gear..... parts is parts. ..spinning is spinning. Think outside the props... everything on top of the leg is spinning... trust us.... trim down when the engine is running... 

Interesting!  I just assumed the shaft only spun when in gear.  Great info and good to know.  (Showing my ignorance)  :)

 

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2 hours ago, Wingnut said:

The outdrive input shaft slips into the engine flywheel coupler so as others have said, if the engine is running, the top bearing and gear set are turning. The shift mechanism on a Volvo Dual Prop or Bravo drive is in the upper gearcase of the out drive. On a Alpha drive it's a dog clutch in the foot, just ahead of the propeller.

We beat this to death but as the manual states, running the engine with the drive in or near the full up position is not recommended, and should be reserved for idle only operations in very shallow waters. The angle is not the issue, again as stated in the manual. The constant velocity dual u-joints could care less, and the gimbel bearing is slip fit designed to compensate, and the engine couple is a lubricated spline, which also could care less what the drive angle is. The problem is that as the drive reaches the upper limits of trim up, the side "ears" exit the gimbel ring and looses the required side support for high torque operation. Idling into a beach with the drive 80% up is not an issue, but if you were to hit something at that moment, severe damage is much more likely. Storing a drive in the full up induces strain to the drive shaft bellows as they take a set over time and are more likely to fail when returned to service. Again the other mechanical's could care less.  W

Excellent (as always)!  Thanks Wingnut!

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