Removing spacer in trim cylinders for more down sterndrive trim?

[Gunn]

So I am rebuilding all four of my trim cylinders on my Alpha I Gen II drives. They end cap on each cylinder was corroded, preventing the drive from moving downward.

In re-assembling the cylinder unit, the Mercruiser service manual mentions a particular spacer that is assembled on the cylinder rod end (the Shock Piston Assembly) and says it can be removed to obtain more downward trim of the drive unit. It also says that the manufacturer of the boat may or may not have included this, and if removed to look out for bow steer, chine walking, etc. and other possibly issues becuase of it.

At this point, all of the cylinders have been re-assembled, but I still haven't put them back on the drive. So I still have time to re-think my decision and remove them before I add fluid and purge the air from them.

I considered it because in certain angry sea states, I have the drive full down and the tabs full down and yet it still seems I have a rather overly bow-high attitude. And under normal calm conditions, I trim up a bit (with tabs up) but have a lot of room still remaining to trim upward, to remove this spacer.

I vaguely recall a post by Dave S. several years ago concerning the 260DA and a similar spacer, but heck if I can find it.

Does anyone have any thoughts pertaining to this, and/or the 280DA specifically?

Thanks,

Tom

 

[Bucit]

Interesting thought. I'm sure it would help with hole shots and getting up on plane quicker too.

 

[Lazy Daze]

Save your time - put it back together and get boating, Tom. That's only on the Bravo drives.

 

[kkalsch]

The spacer your thinking about is on the Bravo 3 (the celery stick) the Alpha drive does not have that
What Dennis said

 

[keokie]

I don't think he is talking about the celery stick (but that is a great piece of knowledge for Bravo owners). I think he is referring to a block that is INSIDE the trim cylinders.

 

[Gunn]

Save your time - put it back together and get boating, Tom. That's only on the Bravo drives.

Dennis, I'm not bluffing here. I know what I read. I have the correct Mercruiser Service Manual for my Alpha drive. And as I said, I have already taken it apart, and I have this spacer within my trim cylinder, installed on the unit.

I can't wait to go boating, and to remove them wouldn't take any time at all to do at this stage in the project anyway ...

 

[Gunn]

Here's the spacer (b) I'm talking about. I have this spacer on my trim cylinders. From the Mercruiser Service Manual:

IMPORTANT: The new trim cylinders provide the capability for an increased Trim-inrange. Spacer (b) can be removed from the trim cylinders to increase the Trim-in range by approximately 1-1/2 degrees. This will improve the acceleration on some boats by forcing the bow down more quickly. If spacers are to be removed, the boat must be tested to ensure the increased Trim-in range does not cause any undesired boat handling characteristics (bow-steer, chine-walk, etc.) if the drive is trimmed-in while the boat is operated at higher speeds. The boat should be tested under all conceivable load conditions and maneuvers to ensure that the additional Trim-in does not pose a problem. The final decision and responsibility for use of the additional Trim-in range is left up to the boat manufacturer.

 

[Lazy Daze]

Dennis, I'm not bluffing here. I know what I read.

I didn't think you were "bluffing". As Keokie surmised, I thought you were referring to the "celery stick" as that can be referred to as a spacer. I'll let Jason say for sure, but I also vaguely remember his post and I recall him referring to the celery stick... unless he did more than one post .

Sorry, I can't offer anything on removing the spacer you are referring to. I don't have any experience with it in reference to what you want to know.

But, in simply reading what you posted, I wouldn't hesitate to do it if I was in your shoes and wanted a little more oomph. Let's face it, that's basically a CYA on Merc's side. Ultimately, the captain determines what is safe/not safe. Trimming all the way down at high speed is something that we all already know is not a good thing. The way to avoid that? Simple... just don't do it!

EDIT: Heck, it's not like it's going to trim down by itself. Well, if it had a leak it might, but you'd also immediately notice that your boat is doing something funny and would take corrective action.

 

[Gunn]

Thanks for the comments. So I guess I may just step into uncharted territory and try this out. It's not like I'm going to lose any trim on the opposite end (up trim), and it can only help on initial acceleration. With a full load of people, I've had to use full down trim tabs to get going, and even then the boat struggles a bit and takes awhile to get on plane. With this mod, I'm guessing that will be much improved. Then I can tilt the drive up as usual and be on my way.

Same goes for rough seas, it will give me a bit more down trim to stay on plane at a minimum speed and cut through the waves better. And if it doesn't work out...well there is always the offseason...

I think I've sold myself...any other comments!?

Tom

 

[Bucit]

Gunn, please keep us informed as to the overall result. This may help out a lot of us 280DA owners with the 4.3l's and the slow planing with a full load.

 

[kkalsch]

Well...on a selfish note: do it! -I have the same issues that you have -I know when I changed the location of the celery stick on my 240 (which had a Bravo 3 ) there was a difference and you had to trim up or the bow would plow the water. The way Mercrusier sets up the drive package is fail safe

 

[Bucit]

I doubt the 280DA will plow the water when fully loaded. It's so ass heavy it's not even funny.

 

[kkalsch]

I doubt the 280DA will plow the water when fully loaded. It's so ass heavy it's not even funny.

Nothing wrong with that........kinda like the girls Gary dated in college......

 

[dlvwill]

I removed the spacers on my old Caravelle with an Alpha and flipped the celery stick on the B3 on my 220. Gives you an additional 2 degrees down which was very useful for all the watersports we do. No handling problems with either boat at speed even with the drive tucked in.

 

[OldSkool]

Removing the spacer should not be an issue. Stop position is limited by the bolt head bottoming on the barrel. Just use a bolt that is shorter by the same thickness of the spacer after it is removed. This is done with Hydraulic cylinders of all types and will not hurt anything as long as the rod is long enough so as the external eye does not jam against the barrel when fully retracted.

 

[Gunn]

Thanks guys, it's a done deal. I have all the cylinders reinstalled. My wife and I purged the air from them yesterday, and they are finally working beautifully once again. We'll see how she does once she splashes in about two weeks! I'm excited about it.

Tom

 

[keokie]

Two weeks?? We gotta wait two weeks?! You're killin' me. I gotta know if it is better!!!

 

[JKTOWN]

Two weeks?? We gotta wait two weeks?! You're killin' me. I gotta know if it is better!!!

WHAT EVER HAPPENED ????? just read article from May. What was the final outcome ? thanks

 

[Gunn]

Wow, sorry for never following up on this. Life got in the way I guess. I wish I would have updated sooner. Welcome to the forum!

We didn't get to use the boat near as much as I hoped to this year. In any case, I would say removing the spacer did help...but not a lot. Barely noticeable really. And now at this point, I can honestly say that I had forgotten all about doing it. I know the first time I went up on plane in the spring I was worried about bow steer, etc. But it really ran well.

I didn't get into any really nasty seas this year (like the previous year) when trimming full down and with tabs down really helps combat the pitching. But that would also be hard to compare at this point.

So all in all, if you ever have to rebuild your cylinders, I say take out the spacers. But I wouldn't bother going through all that work just for the sake of removing them.

Tom

 

[chad geetter]

Well...on a selfish note: do it! -I have the same issues that you have -I know when I changed the location of the celery stick on my 240 (which had a Bravo 3 ) there was a difference and you had to trim up or the bow would plow the water. The way Mercrusier sets up the drive package is fail safe

I just found out about the celery stick on my bravo three. I had the same idea of switching it to the other position so the drive was that much lower to help with unwanted bow rise. Is there any harm in trying?