Vibration on down trim
 

Today my boat had a strange shutter or vibration on down trim only. It's very brief only on plane and when you tap the switch for trim down. It goes away after a second and the rest of the down trim travel is smooth and no vibration. I check the gimble ring for slop and the coupler to see if there was binding or rubber, but they booth appeared fine. When the boat is on the trailer and some one hits the down trim I can feel it very slightly shutter for a brief second. I had the rams apart last year and added the trim limit bushing since I replaced the drive. When apart the fluid looked good and I changed it anyways. I don't know where the best place to start is, maybe change the fluid again or is this a sign the pump is going bad? Up trim works fine.

Thanks
Michael

Usually; it is a tight spot, in the rams or check the hinge pins.

Thanks MER I'll pull the rams and busings apart and lubricate.

Hold on!!!!! First; the end caps can corrode; causing the o-ring, scraper to seize around ram. You can buy; rebuild kits that will include these parts. If the caps are corroded; to bad, they will need replaced. You will need a pin spanner wrench, also to remove the cap, the piston has to come off also. The bolt that holds it is secured with red loctite, then you will have to follow the proper bleeding procedures, when finished .

When I added the trim limiter spacers last year the caps looked great and so did the ram internals. No corroding on the caps the boat is a low hour 99 year modle fresh water only. It's weird becuase I have used it several times since adding the spacers last year and it worked fine, just started it the last trip out after sitting for a month. Unfortunately the season is mostly over till next year due to drought conditions so I might not be able to test until next season if we get rain. Its hard to tell if it's doing it on the trailer but is very notiacble at speed but brief maybe a second at most. I was kinda of stumped and searched the formum and doesn't seem like a common problem. Also as far as I can tell the whole trim system is original circa 99 merc stuff. Maybe the I over tightened the bushings in rams but so don't think so.

Couple of things. One is your hinge pins properly torqued ? You should have the grease jerks for that area as well. How long has it been since they were last greased.

Also your problem could be the valve body of the trim unit itself. What condition is your trim fluid ? Do you have air in the system or any form of water in the trim fluid ? If you pull the trim reservoir off the unit - you will see two screens on the inlet and outlet portion of the bottom of the valve body that rests in the trim fluid when the reservoir is intact. Make sure those 2 screens are clean and free of any debris.

Do U have the spacer installed that goes thru the rear of the outdrive where the back trim ram pin goes through. The white plastic spacer. Actually we call it the celery stick because it looks like that.

Could it be a burr on the drive shaft or worn coupler?

BUP,

Yes the celery stick is in there right. I didn't think there were grease zerts in the hinge pins because it's a HP gimble assembly

Buck,

I thought the couple too because went the drive blew it twisted the splines in input shaft. It's just strange because it just started this and I have put almost 30 hrs and two seasons since I replaced the drive. I would think it would do it all the time or on up trim too. Boat runs smooth the rest of the time. In check the alignment last winter and it seems fine. Tool slid in. There might have been a couple of burs on the coupler when the drive was replaced 2 yrs ago but it seemed fine. Hate to pull it for coupler if that is not the issue.

Thanks for the help guys

Maybe if you unpin the rams from the out drive and throw a rod in to connect them run up and down to see if the vibration is still there with pressure against them , if not manually lift and lower drive to see if there's any resistance, still nothing maybe a u joint on it's way out? Wild azz guesses, good luck!

Was there ever a resolution to this? I have the EXACT SAME PROBLEM. Actually, I had my boat repaired by Marine Max for an electrical problem and the also pulled the lower unit to check on something else. When I got the boat back, there is a very distinctive shutter when you trim down. Only lasts for 1/2 a second or so. They took the boat back and could not figure out why. So, they said that my transom is bad and there is nothing they can do. It's a 2001 with 680 hours on it. We float the boat all summer on our dock and they are telling me that it's waterlogged. I don't believe this is the problem so they returned the boat to me. This started after they pulled the lower unit and put it back.

When they were trying to determine why, they also replaced the U-Joints telling me that was the problem. It did not resolve the issue. Boat is in solid sound shape. Now I'm stuck with a problem that Marine Max (which is the Sea Ray dealer) is washing their hands of.

Ping Donzi1979 if you see this, maybe you can share your resolution.

Please help!

Sorry, my first post but I think your expertise may be able to help.

If I need to start a new forum post, just tell me and I will :)

EddieRock