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cheniermudder
MMT Pro Member
Joined: Mon Apr 06, 2015 8:30 am Posts: 434 Location: SW Louisiana - Sabine River
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 Motor mounting dampers
I was wondering if anyone has ever tried mounting rubber dampers between the motor and frame to try to reduce some of the vibration. Outboards have them, automobiles have them, seems it would at least HELP reduce some of the vibration. This would definitely require replacing the belt since the motor would set higher, but how would you determine what length belt would be needed without going thru a bunch of belts? Would softening the seat between motor and frame cause issues with the belt as well. Probably not a tangible solution, or one of the manufacturers would be doing it.
I'm sure someone else has probably considered this. Just wanted some input from the experts.
Thanks in advance.
_________________ 2010 31hp GT on a 1648 Alumacraft Jon Boat
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Mon Jun 08, 2015 3:11 pm |
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mudxxed
MMT 1000 Club
Joined: Thu Sep 05, 2013 4:46 pm Posts: 1398 Location: SE Bama
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 Re: Motor mounting dampers
bump. curious as well
_________________ 1651 Excel/ 35 MB HD: little of dis, little of dat
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Fri Jun 12, 2015 1:14 pm |
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HOTSAUCE170
MMT 1000 Club
Joined: Thu Jun 05, 2014 11:44 am Posts: 1685 Location: Lake Blackshear,GA
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 Re: Motor mounting dampers
I'm no engineer by no means but if you mount the motor on rubber dampners or anything to absorb vibration they will also flex some with the torque of the engine. The engines mounted rigid doesn't require the use of a tensioner on GT GD, mudbuddy has one I think but since the engine doesn't move the belt doesn't require tensioning. The rubber mounts sound like a great idea for vibration issues but would require a variable tensioner "like on a serpentine belt" to compensate for the engine moving some. Another issue I see as I think is what would keep the belt from walking off of the back of the pulley if engine flexed towards the rear meaning the output shaft pointed downward and the fan housing went up. As for a pro drive I don't see why they couldn't mount the vertical engine with these from the start.
_________________ I named my boat RIANNA cause it gets beat up all the time
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Fri Jun 12, 2015 1:38 pm |
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cheniermudder
MMT Pro Member
Joined: Mon Apr 06, 2015 8:30 am Posts: 434 Location: SW Louisiana - Sabine River
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 Re: Motor mounting dampers
I had considered the need for an adjustable/variable tensioner, tho how you would work it into the unit is beyond me. If the top drive gear had a plate/lip on the back to act as a stop, I think this would keep the belt from riding off when the motor flexed, but it would need to be a high enough lip to keep the belt fron jumping over and getting ate up ( and possibly a thicker belt to prevent it from cupping over the lip ). Or........Possibly even redesign the belt and gears to include a bevilled ridge in the middle of the belt running the length of the belt ( across the teeth) and a groove in the middle of each gear for the new ridge to ride in. I know there are more specific terms to describe this but hopefully y'all get my drift.
Aint it amazing how making one small change nesecitates so many others?
If no-one has developed this into a motor by the time I'm ready to get another one, i think i'll keep this one to experiment on, lol
_________________ 2010 31hp GT on a 1648 Alumacraft Jon Boat
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Fri Jun 12, 2015 4:47 pm |
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HOTSAUCE170
MMT 1000 Club
Joined: Thu Jun 05, 2014 11:44 am Posts: 1685 Location: Lake Blackshear,GA
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 Re: Motor mounting dampers
Your right about changing one and having three more things to fix! But I was thinking about the tensioner mounting to the belt housing and pushing on the backside of the belt just below the top pulley . I would use a belt that's longer so the tensioner would push the belt to the other side of itself but not touch and clear the side of the housing when releasing tension
Sent from denda this
_________________ I named my boat RIANNA cause it gets beat up all the time
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Fri Jun 12, 2015 5:38 pm |
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banded-mallard
MMT 1000 Club
Joined: Wed Oct 07, 2009 8:18 pm Posts: 4310
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 Re: Motor mounting dampers
I'm a vibration specialist and check shit like this on a daily basis. You will have some serious problems in doing this. Yes, it will help vibration, but as the engine vibrates, the belt alignment will get off. That is the key to belt longevity. The rest of the system is rigit, except the engine. The slightest misalignment and turning that fast, will allow the belt to wear prematurely. Seen it 1000 times in the plant. Now, if you want to have dampeners on the handle or even on the motor where it mounts to the hull, but don't do just the engine with the remaining pieces rigit. JMO though.
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Fri Jun 12, 2015 7:27 pm |
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bayouboy
MMT Elite Member
Joined: Tue Jan 13, 2009 6:08 pm Posts: 5376 Location: Venice, La
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 Re: Motor mounting dampers
^^^ Pessimist!! 
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Sat Jun 13, 2015 7:29 pm |
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cheniermudder
MMT Pro Member
Joined: Mon Apr 06, 2015 8:30 am Posts: 434 Location: SW Louisiana - Sabine River
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 Re: Motor mounting dampers
I just wonder if you were to take a set of rubber stoppers drilled out to allow the motor mounting bolts to pass thru and use them as seats for the motor if it would reduce the vibration? Yes there would be a degree of flex in the motor, thats a given. But how much flex can the belt withstand? It would still be a pretty solid union. Also, how would you determine what length belt you would have to swap to with the given lift of the motor? Is there a specific measurement, point A to point B dimension that will tell you what length belt you need?
_________________ 2010 31hp GT on a 1648 Alumacraft Jon Boat
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Sat Jun 13, 2015 8:10 pm |
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bayouboy
MMT Elite Member
Joined: Tue Jan 13, 2009 6:08 pm Posts: 5376 Location: Venice, La
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 Re: Motor mounting dampers
The engine would have to be raised and a longer belt purchased. You'd be better off insulating the tiller. also not sure about the longer belt and slap (flapping) or if you would need to incorporate an idler pulley.
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Sat Jun 13, 2015 8:23 pm |
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brycecheramie
MMT 1000 Club
Joined: Thu Nov 04, 2010 7:38 am Posts: 4323 Location: Cut Off, La.
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 Re: Motor mounting dampers
_________________ Refurbishing a Prodrive
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Sat Jun 13, 2015 8:27 pm |
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bayouboy
MMT Elite Member
Joined: Tue Jan 13, 2009 6:08 pm Posts: 5376 Location: Venice, La
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 Re: Motor mounting dampers
^^^ This guys on to something! 
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Sat Jun 13, 2015 8:28 pm |
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brycecheramie
MMT 1000 Club
Joined: Thu Nov 04, 2010 7:38 am Posts: 4323 Location: Cut Off, La.
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 Re: Motor mounting dampers
_________________ Refurbishing a Prodrive
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Sat Jun 13, 2015 8:29 pm |
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msm8281
MMT Elite Member
Joined: Fri Oct 09, 2009 1:50 pm Posts: 9673 Location: New Iberia, La.
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 Re: Motor mounting dampers
Mine only vibrates over 27mph. I'm pretty sure that's why the PDs don't vibrate cause they never reach that speed. 
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Sat Jun 13, 2015 8:38 pm |
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brycecheramie
MMT 1000 Club
Joined: Thu Nov 04, 2010 7:38 am Posts: 4323 Location: Cut Off, La.
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 Re: Motor mounting dampers
_________________ Refurbishing a Prodrive
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Sat Jun 13, 2015 8:50 pm |
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bayouboy
MMT Elite Member
Joined: Tue Jan 13, 2009 6:08 pm Posts: 5376 Location: Venice, La
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 Re: Motor mounting dampers
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Sat Jun 13, 2015 9:00 pm |
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msm8281
MMT Elite Member
Joined: Fri Oct 09, 2009 1:50 pm Posts: 9673 Location: New Iberia, La.
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 Re: Motor mounting dampers
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Sat Jun 13, 2015 9:01 pm |
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JLACOUR
MMT 1000 Club
Joined: Wed Jan 14, 2009 8:18 pm Posts: 4915 Location: Lake Jackson, TX
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 Re: Motor mounting dampers
_________________ 37 PD EFI FPR 18x48 Tiller SOLD -- 36 PD EFI FPR 18x48 Stick Steer SOLD -- 27 PD FPR 16x36 Skiff
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Sat Jun 13, 2015 11:24 pm |
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cheniermudder
MMT Pro Member
Joined: Mon Apr 06, 2015 8:30 am Posts: 434 Location: SW Louisiana - Sabine River
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 Re: Motor mounting dampers
Have I complained about vibration? No. Have I tried knocking one brand versus another? No. I am purely trying to instill some thought into improving on an issue that several operators have mentioned/complained about. And while there has been some much appreciated input regarding the issue, no-one has yet to answer how to determine what belt length would be needed. If I decide to persue the issue first hand, I would like to know how to go about replacing the belt to match the new motor height. Does anyone know the formula? I guess when/if the time comes I'll just take a string and measure the entire circumferance around the loop around both gears and hope the vendor can tell me what length belt I need.
Bayouboy....if one were going to try to insulate the tiller, any suggestions on how to do that? Would stacking a series of neoprene washers at the each side of the pivot point do the trick?
_________________ 2010 31hp GT on a 1648 Alumacraft Jon Boat
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Sun Jun 14, 2015 8:02 am |
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HOTSAUCE170
MMT 1000 Club
Joined: Thu Jun 05, 2014 11:44 am Posts: 1685 Location: Lake Blackshear,GA
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 Re: Motor mounting dampers
_________________ I named my boat RIANNA cause it gets beat up all the time
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Mon Jun 15, 2015 7:57 am |
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Will
MMT Elite Member
Joined: Fri Jul 08, 2011 1:54 pm Posts: 8133
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 Re: Motor mounting dampers
_________________ Before the internet, the majority of the village idiots stayed in their villages.
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Mon Jun 15, 2015 11:23 am |
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cheniermudder
MMT Pro Member
Joined: Mon Apr 06, 2015 8:30 am Posts: 434 Location: SW Louisiana - Sabine River
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 Re: Motor mounting dampers
To be honest, I hadn't thought of a handlebar insert. As soon as I get my rig back (next couple of days hopefully) I'm going to have to look into that. Again, I not really too concerned at this point. My biggest issue currently is reducing my torque, which is job one when I get it home. Just put a new LU on it before it went into the shop and haven't had the opportunity to tune in or possibly shift the motor over.
I was just curious if anyone had ever put any effort into the subject of vibration. Something to think about....
_________________ 2010 31hp GT on a 1648 Alumacraft Jon Boat
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Tue Jun 16, 2015 2:30 pm |
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