Twisted I/O Drive.

[ChrisV]

Hey guys,

While I should wait for the lower unit to come this is something thats really bugging me. I recently put on a SCX upper and noticed the center line of the drive is off. Once I put on the lower unit, it will exaggerate it even more. The lower unit will be to the right side of the drain plug. Is this something moves over time? My friend said the gimbal might be bent.

Or do I remove the standoff box, and helmet assembly and realign the whole thing? New to boats so please help me out here. Also have a free day tomorrow so would like to address this.

 

[RadMan]

Move your camera to the right a little bit and snap new pics, it will be fixed.

J/K I have no help to give, best of luck fixing this. Please share, that’s interesting as much as it seems to suck.

 

[wet hull]

Is the drain plug perfectly centered? I would think as long as motor and drive are aligned the rest would only effect it leaning to 1 side potentially, but given prop spin that might counter that regardless. In the end I have no clue

 

[JFMFG]

Honestly I need you to come work for me. Your attention to detail is amazing. Like stated is it possible the drain plug is off center? I would think if motor and drive was aligned you’re good. Maybe it’s been like that? Idk.

 

[ChrisV]

Honestly I need you to come work for me. Your attention to detail is amazing. Like stated is it possible the drain plug is off center? I would think if motor and drive was aligned you’re good. Maybe it’s been like that? Idk.

It’s a curse imo. I checked the drain plug and it’s centered. I’m probably gonna throw the old drive on today to check.

 

[4Waters]

Is the drain plug perfectly centered? I would think as long as motor and drive are aligned the rest would only effect it leaning to 1 side potentially, but given prop spin that might counter that regardless. In the end I have no clue

Honestly I need you to come work for me. Your attention to detail is amazing. Like stated is it possible the drain plug is off center? I would think if motor and drive was aligned you’re good. Maybe it’s been like that? Idk.

Drain plug does look off center and a tape measure will answer that but this doesn't look level between the drive and the hull

 

[ChrisV]

Drain plug does look off center and a tape measure will answer that but this doesn't look level between the drive and the hull

View attachment 1431189

So the cavitation plate was bent on the first drive. IMCO exchanged it for me. New one is good which is the first pic.

 

[4Waters]

So the cavitation plate was bent on the first drive. IMCO exchanged it for me. New one is good which is the first pic.

Ok, both pictures are at a slightly different angle so I couldn't tell, just went off the 2nd pic measure the plug

 

[CSmith]

My Eliminator Fundeck was the same exact way. My little pea brain was thinking more about it and I wonder if they do that on purpose to accommodate "flex" for lack of a better term or when the prop is spinning the opposite way the drive goes etc. Maybe someone with actual facts can chime in but that was one thing that drove me crazy. When the prop is on its even worse. IMO.

 

[ChrisV]

My Eliminator Fundeck was the same exact way. My little pea brain was thinking more about it and I wonder if they do that on purpose to accommodate "flex" for lack of a better term or when the prop is spinning the opposite way the drive goes etc. Maybe someone with actual facts can chime in but that was one thing that drove me crazy. When the prop is on its even worse. IMO.

Boat drove fine?

I’m just gonna go with this.

 

[Singleton]

@Tony DCB Boats
When it comes to DCB, best to ask Tony and he will get you an answer.

 

[CSmith]

Boat drove fine?

I’m just gonna go with this.
View attachment 1431192

To me it did. I am buy no means a pro though so maybe "normal" wasn't normal. I put over 400 hours on it before selling.

Had 2 totally different drives on it in that time period and even took the entire transom assembly off and replaced gaskets when I went full hydraulic.

 

[lenmann]

I think you're theoretically correct. In a perfect world the plug for the hull mold would have been CNC machined to tight tolerances, the lamination processes would have been tightly controlled to assure no warp, shrink or twist, the machining processes used for the standoff box and drive components would be held to very tight tolerances, and when the guy rigging the boat drilled/cut the holes for the drive assembly alignment of the fixture to the hull would be tightly controlled.

Reality in the recreational boating world is quite different than what I described above, especially during the era your DCB was built. That coupled with the fact that the drive assembly extends off the back of the transom some 3-4 feet, any deviation at the mounting surface gets extrapolated to look even worse.

I learned some of this first hand when I rigged my Schiada. Trying to find the geometric "true north" of the hull is near impossible. The wetted surface isn't symmetrical side to side (one side is 1/2" wider than the other) and trying to find the center of the keel to align the blades of the turn fin and prop shaft strut perpendicular with the line that bisects the hull is near impossible. In the end the whole thing is a best effort kind of deal. I am a machinist by trade and very comfortable working with tight tolerances, turning that part of my brain off was very hard. I share the same sickness you have with seeing shit that looks off a little and then obsessing a bit.

I say just run the shit out of the boat. The minor deviations and stack up of tolerances that are creating the visual discontinuity are not meaningful to how much fun the experience of using the boat creates.

 

[wzuber]

I think you're theoretically correct. In a perfect world the plug for the hull mold would have been CNC machined to tight tolerances, the lamination processes would have been tightly controlled to assure no warp, shrink or twist, the machining processes used for the standoff box and drive components would be held to very tight tolerances, and when the guy rigging the boat drilled/cut the holes for the drive assembly alignment of the fixture to the hull would be tightly controlled.

Reality in the recreational boating world is quite different than what I described above, especially during the era your DCB was built. That coupled with the fact that the drive assembly extends off the back of the transom some 3-4 feet, any deviation at the mounting surface gets extrapolated to look even worse.

I learned some of this first hand when I rigged my Schiada. Trying to find the geometric "true north" of the hull is near impossible. The wetted surface isn't symmetrical side to side (one side is 1/2" wider than the other) and trying to find the center of the keel to align the blades of the turn fin and prop shaft strut perpendicular with the line that bisects the hull is near impossible. In the end the whole thing is a best effort kind of deal. I am a machinist by trade and very comfortable working with tight tolerances, turning that part of my brain off was very hard. I share the same sickness you have with seeing shit that looks off a little and then obsessing a bit.

I say just run the shit out of the boat. The minor deviations and stack up of tolerances that are creating the visual discontinuity are not meaningful to how much fun the experience of using the boat creates.

I tend to agree w/ the above, especially in a recreational application. Commonly, these boats ( in general) are anything but symmetrical. Maybe the newer generation boats are better then the 70's/80's era hulls? IDK
My experience is limited to setting jet pump intakes and as stated above locating the keel c/l becomes a best compromise situation. Fortunately for me they all ran significantly better afterward so I felt good about the choices made.
I would hope Tony can help clarify your situation and look forward to what his input here would be. I can imagine the drive being off center that way would lead to some driving input correction required to run straight. How much "slop" is there in the mounting assemblies? A little there can translate to what your seeing. Have you checked to see if each component is parallel to the transom as you install ea. Section such as the std. Off box etc.?
There's so many variables w/ components in these things it's a real challenge to insure and verify exactly how true they all are.

 

[lbhsbz]

Some hulls are crooked on purpose, some are crooked not on purpose.

I’ve mounted outboards on 2 boats after transom replacement (from the inside…didn’t change the boat) and finding a center point is challenging, or impossible. I measure from every possible edge and end up with a cluster of dots…then put a big one right in the middle and use that as my starting point.

 

[SOCALCRICKETT]

Some hulls are crooked on purpose, some are crooked not on purpose.

I’ve mounted outboards on 2 boats after transom replacement (from the inside…didn’t change the boat) and finding a center point is challenging, or impossible. I measure from every possible edge and end up with a cluster of dots…then put a big one right in the middle and use that as my starting point.

This, if I recall the podcast "schiada stan" did he talked about the slight differences hulls can have as far symmetry goes. I wouldn't be surprised if the drive is offset for torque steer purposes...


Then again with that much of a standoff off box it's tough to get everything dead nuts square

 

[GETBOATS]

Some hulls are crooked on purpose, some are crooked not on purpose.

I’ve mounted outboards on 2 boats after transom replacement (from the inside…didn’t change the boat) and finding a center point is challenging, or impossible. I measure from every possible edge and end up with a cluster of dots…then put a big one right in the middle and use that as my starting point.

This is very true, I would start with long straight edges from every point, it may not be as pronounced as the pictures.
I can commiserate though, I can myself going down the rabbit hole trying to make it perfect.
We all need to remember boats are 100% hand made from mold to finished product.

 

[Ziggy]

To me the only real affect would be the unequal port/starboard lean in turns, straight line driving not so much.
The photo gives me this impression

 

[RiverDave]

That is bizarre..

 

[lbhsbz]

The drain plug is not centered....not even close. Find the center of the keel and put a sharpie dot....then re-eyeball it, it'll look a lot better.

 

[Done-it-again]

Put your degree finder back on to see if the drive is setting perpendicular.

 

[lakemadness]

The drain plug is not centered....not even close. Find the center of the keel and put a sharpie dot....then re-eyeball it, it'll look a lot better.

100%

 

[lbhsbz]

Put your degree finder back on to see if the drive is setting perpendicular.

Then adjust trailer tire pressure until it’s level.

 

[lakemadness]

Put your degree finder back on to see if the drive is setting perpendicular.

Yes, and use the steering wheel to adjust the drive angle and dial it in 90 degrees from the stern. Fixed!

 

[GETBOATS]

Drain plug centered or not, what catches my eye is center pods horizontal lines don't match drives anti vent plate. However if we took this close a look at most boats regardless of price we'd find this in some cases.

 

[lakemadness]

Your drive is not "twisted". Maybe, and I say, maybe it's not centered perfectly. Or your drain plug is not centered. Or the curvature of the center sponson is not symmetrical. A lot of things on boats are not centered or symmetrical, you can drive yourself batshit crazy chasing it... Either way, the boat works well, right? Dont fix what's not broken.

This is free advice, so you know...

 

[ChrisV]

Drain plug is off .250" from center.

I ended pulling the gimbal assembly off. Theres slight play in the bolts to the standoff box. Just pulled the lower section of the drive towards the left and tighten everything. Silicone the assembly and put it back on with the alignment tool. Much better now.

@lenmann I could see you going crazy over boats because you're a machinist. I'm happy to feel I'm not the only crazy one. haha

 

[ChrisV]

Your drive is not "twisted". Maybe, and I say, maybe it's not centered perfectly. Or your drain plug is not centered. Or the curvature if the center sponson is not symmetrical. A lot of things on boats are not centered or symmetrical, you can drive yourself batshit crazy chasing it... Either way, the boat works well, right? Dont fix what's not broken.

This is free advice, so you know...

Just out here learning. I'm very new to boats so figured i asked if theres a problem. Something I might of missed. Also my first drive swap.

 

[GETBOATS]

Great, now the anti vent plate and trim ram thru bolt lines up with center pod lines and top of tunnels.

 

[ChrisV]

Great, now the anti vent plate and trim ram thru bolt lines up with center pod lines and top of tunnels.

Tweeked out

 

[lakemadness]

Just out here learning. I'm very new to boats so figured i asked if theres a problem. Something I might of missed. Also my first drive swap.

You're way ahead of me. I've never taken a drive off/on. Cheers! Badass boat btw.