Dpsm duo prop boat shake /wobble

Desjr72

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Sep 17, 2019
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So I have a weird problem that started recently. I was backing into my slip and all of a sudden the stern of the boat started to shake or wobble Side to side . I put it into neutral and back in reverse a few times and it stopped. It doesn’t happen every time I go out but it has happened a few more times since the first time . I would have bet I had something wrapped around a prop or even a bent blade the way it was acting . I checked the props and they look perfect. My boat has 2 5.0 engines with dpsm 195 duo prop drives . I have no issues underway, only seams to happen at idle speed, mostly in reverse. Has anyone experienced anything like this ???????
 

GA_Boater

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Welcome aboard.

Is this occurring in reverse, forward or both. Is it only happening in your slip or also in open water?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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make sure your revers latch is working.

you may have a drive coming up in reverse, and the shaking is the u-joints tearing themselves apart.

time to pull the boat and look
 

alldodge

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Agree, need to look, but may also be the prop nut(s) have loosened
 

QBhoy

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Mar 10, 2016
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I’m with the reverse latch not catching and the drive throwing itself up to the surface. Common on true older dp. Maybe not so much on these though.
 

muc

"Retired" Association of Marine Technicians...
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Jul 7, 2004
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Don't think Iv'e ever seen a reverse latch on a DP-SM.

Iv'e had a few Volvo's that would sometimes get the steering oscillating But it's usually happens in neutral.
Don't know what causes it. My guess is it's something in the power steering control valve. Never tried replacing that because they are so expensive. And a lot of work.

What I have tried successfully, is to add some more plastic washers to the bottom swivel pin on the TSK.
part number 3852557 They are less than $2.00 each. Might be worth a try.
 

BRICH1260

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Don't think there is a reverse latch on a VP. Your linkage may need some adjusting as your cone clutch may not be completely engaging the reverse gear.
 

89retta

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Jul 18, 2010
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772
I have the same problem sometimes. Single engine 4.3 gxi with a sx outdrive. It will rock the whole boat side to side like something is out of balance. Only happens at start up when it does happen. It all depends on on how my drive is tilted usually around the halfway mark. Goes away once I trim it down . Still dont know what causes it though.
 

dypcdiver

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Nov 1, 2005
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Happens on my DP-SM but only when everything is hot, after pulling mono skier and selecting neutral and very occasionally when going astern into my mooring and selecting neutral. I go along with muc and suspect there is something going on in the power steering control valve.
 

C-Rad

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Aug 4, 2015
Messages
8
Mine did this as well. intermittently while idling or moving slow. Lower unit does a little jiggle back and forth and shakes the boat. Its the steering ram. check your bilge or reach back behind the engine and chances are you will have power steering fluid leaking. I am going to pull mine this winter and send it off to an outfit in Florida that rebuild these. You have to send yours in first. Then they send you one that's rebuilt already for 280 bucks. Cheaper than paying about 700 for a new one. Seems like this steering ram is a common problem. They do sell rebuild kits but I am not going to chance it as I believe you need some specific tools and replacing the seals requires some kind of magic. Plus depending how easy it is to remove and reinstall. Looks like removal of manifold risers is needed to get to it better.
 

enginesilo

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Jun 9, 2008
Messages
355
Mine did this as well. intermittently while idling or moving slow. Lower unit does a little jiggle back and forth and shakes the boat. Its the steering ram. check your bilge or reach back behind the engine and chances are you will have power steering fluid leaking. I am going to pull mine this winter and send it off to an outfit in Florida that rebuild these. You have to send yours in first. Then they send you one that's rebuilt already for 280 bucks. Cheaper than paying about 700 for a new one. Seems like this steering ram is a common problem. They do sell rebuild kits but I am not going to chance it as I believe you need some specific tools and replacing the seals requires some kind of magic. Plus depending how easy it is to remove and reinstall. Looks like removal of manifold risers is needed to get to it better.

Sounds like you hit this one right on the head from experience. I once saw this video and it always stuck with me, after troubleshooting he finally figured out it was power steering related too

https://youtu.be/yMW_dyPXVpc
 

Cobe Marine

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Oct 5, 2019
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I have the same problem sometimes. Single engine 4.3 gxi with a sx outdrive. It will rock the whole boat side to side like something is out of balance. Only happens at start up when it does happen. It all depends on on how my drive is tilted usually around the halfway mark. Goes away once I trim it down . Still dont know what causes it though.

Just a heads up because we see this all the time......Per Volvo, and even Merc, the engine should never be running without the drive lowered to within the trim limiter's range. This in usually only about 2 inches from all the way down but it actually goes by angle degree in relation to the transom angle. When you run your engine above the trim limiter range (hence the word trim "limiter") you are putting incredible stress on those U-joints......."usually around the halfway mark" is WAY beyond this range.
 

Lou C

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Nov 10, 2002
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Interesting, I recall hearing about this over the years on Volvo SX drives, never experienced it on my OMC Cobra whose transom design Volvo adapted and also the power steering set up is similar but not identical. I can start mine with the drive half way up with no vibs no noise either. Sometimes in shallow mooring areas I've had to do this all season in fact due to the tidal swings where I am located...(7' between high and low tides).
 

Desjr72

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Sep 17, 2019
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9
So I have the boat home now after pulling it for the season . I noticed it happens sometimes when you start the engine . If you shut the engine off and start it back up it’s gone . I did notice some fluid in the bilge and the pump was a little low . Im going to look for a leak . I just replace the steering cylinder last winter . Brand new from Volvo 700$$$ . The old one never did this just leaked . When it was low last year due to the leak it never did this sort of thing . I also noticed it seams to only happen with the starboard engine running. That’s the one that my ps works off of . If it’s running and you push or pull on the drive it starts to do it so I’m leaning towards something in the steering .
 
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Horigan

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Jun 12, 2016
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614
First, you need to be running your engines with a hose and muffs attached to the drive. Maybe both drives, but I don't know how raw water pumping works on a twin engine boat. The raw water pump is couple of feet above your water tank and pump won't self prime, so you're running the pump dry, damaging your impeller, and not cooling your engine.

Second, it looks more like a steering issue than a drive issue.
 
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muc

"Retired" Association of Marine Technicians...
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Replace steering actuator, or see post #6
 

Desjr72

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Sep 17, 2019
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I replaced it last year from Volvo 700 bucks . I guessing could be defective.......
 
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