Trim tabs lowering over winter

[tsp]

I put my tabs fully up in the fall and I noticed that over the winter they have lowered. One has moved more than the other. Is this normal? Or does it indicate a problem?
Thanks

 

[MOBILEMERCMAN]

They shouldn't move

 

[Otis311]

I have movement over the winter too. Is that bad ??

 

[MOBILEMERCMAN]

Maybe there is some air in the system. As far as problems go that is a minor one. If they were to push up while under way that would be worse by far. I would check the level, check fittings and cycle them. When they bind at the end of travel hold for 2 or 3 more seconds. If air is present you will her it pass.

 

[Chris]

Here's how to test- when you're running on smooth water, tab down. If they stay down, you're OK. If they creep upward, you either have bleed by inside the rams or inside the pumps. You can set the tabs down and plug the line fittings on the rams and test again. If the don't mnove, it's in the pumps.

 

[FULL FORCE]

Most lekely in the pumps, there is a ball valve inside pump that plugs the opposite direction, sometimes they get dirty and need cleaned, not a huge deal, I store mine down in the winter, same as drives..

 

[old377guy]

like full force said..

 

[Rookie]

I know I have a pinhole leak where the line meets the transom and the tab will get spongy over the week. Once I run it up and down again all the air works out and then is not a problem. (the tab will drift up a little while on a long run) I will be fixing that before spring.

If you are adding oil you have a leak and air is getting in, if oil level stays constant check what full force or chris said.

 

[tsp]

Thanks for the help. Once it gets warm I'll take the tarp off the boat and have a look. I have tried pushing down on them by hand and they won't budge.

 

[tsp]

Most lekely in the pumps, there is a ball valve inside pump that plugs the opposite direction, sometimes they get dirty and need cleaned, not a huge deal, I store mine down in the winter, same as drives..

I was not sure how to leave the tabs. Good to know.
I was hoping some movment was normal, but I guess I'll have to tear apart the pumps.
Thanks again for the help,
Tom

 

[cpmarine]

When you store your drives down the cylinders are retracted, no pressure on them. When you leave your tabs down the cylinders are extended, under pressure, just the opposite of the drive. I would think if there was a leak the cylinder would retract not extend, this would not let the tab go down. It takes pressure, not a leak to extend the cylinder.

 

[FULL FORCE]

When you store your drives down the cylinders are retracted, no pressure on them. When you leave your tabs down the cylinders are extended, under pressure, just the opposite of the drive. I would think if there was a leak the cylinder would retract not extend, this would not let the tab go down. It takes pressure, not a leak to extend the cylinder.

I am going with the gravity theory on the tabs, if they are left up, gravity wants to pull them down, resulting in pressure, they are extended yes by pressure but at rest when all the way down, thats how I see it anyway...

 

[inbetween]

When you store your drives down the cylinders are retracted, no pressure on them. When you leave your tabs down the cylinders are extended, under pressure, just the opposite of the drive. I would think if there was a leak the cylinder would retract not extend, this would not let the tab go down. It takes pressure, not a leak to extend the cylinder.

I had an external leak on a line in the bilge. The tab would drop while sitting on a lift or the trailer. The weight of the tab pulls down on the piston and creates a slight suction in the line when there is a leak, air gets pulled in through the leak point

 

[Ted]

It is better to leave the tabs up during storage to keep the rams retracted so they don't corrode or pit.