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Stern drive slowly trims down

Old 06-02-2021, 11:45 AM
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Default Stern drive slowly trims down

I got a bravo that slowly comes down over a few days if left trimmed up in the barn. When under power it will also slowly trim down and I have to keep adjusting it.
Is it the seals in the trim rams or something in the trim pump? What's the right way to know for certain?
Thank you.
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Old 06-02-2021, 03:32 PM
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If you don't see oil leaking from the cylinders or an oil slick on the water, likely not the rams. The pumps have a base plate that fluid is controlled by a series of steel balls in an aluminum seat. Those tend to leak after a while causing them to lose pressure. I thought someone made an oversized ball kit, but that's been years since I looked.
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Old 06-02-2021, 09:43 PM
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Its most likely the valves in the trim pump. I had the same issue on a boat years ago. Replaced pump and all good.
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Old 06-03-2021, 06:56 AM
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Is pump replacement the only option for repair? Or is the valve base plate available and replaceable? Or should I just replace the pump regardless since it is 28 years old...
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Old 06-03-2021, 07:34 AM
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I would just put in a new pump. I also used SEI Marine rams on mine, much cheaper than Merc, and 4 years later they still seem just fine to me.

https://www.sterndrive.cc/product/Fi...-98704A26.html
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Griff (06-04-2021)
Old 06-03-2021, 02:45 PM
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Originally Posted by LakeHuronPower View Post
Is pump replacement the only option for repair? Or is the valve base plate available and replaceable? Or should I just replace the pump regardless since it is 28 years old...
It's by far the easiest! I've cracked open several pump bases without roaring success. Some work for a while, others never worked better, sometimes you drop a valve ball and throw the whole thing in the trash (long story) If you look around CL and Ebay, there are some that come up relatively inexpensive.
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Old 06-03-2021, 04:08 PM
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28 years it doesn't owe you anything
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Old 06-04-2021, 07:29 AM
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Thanks for the help.
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