Thread Tools Search this Thread Display Modes
Old 09-02-2011, 01:54 PM   #1
Join Date: Apr 2011
Posts: 3
Default Alpha One Trim Bypass Squeal

Hello Everyone,

I'm working on a problem on a 1998 2300SC w/ the 5.0 Merc and Alpha One. Recently, I've noticed that when trimmed all the way down, The squeal of the trim pump has changed pitch. All of the trim functions work fine, up/down/trailer; it's just that when trimmed fully down, the noise the pump makes during the fluid bypass is now a louder, higher-pitched squeal. I know it's supposed to sound different from the normal operating noise. It's always been a higher pitch during bypass, but now it's obnoxious. Nothing appears to be leaking and the fluid level is fine.

Any help would be appreciated. Thanks.


willin58 is offline   Reply With Quote
Old 09-02-2011, 02:18 PM   #2

Join Date: Apr 2008
Posts: 3,975

Hi Willin58, welcome aboard!!!! Whether you use the Trim In/Out (UP down) button, or the Trailer button, the sound should be the same. The only difference is the Trim IN/Out will be limited in it's range by the Trim Limit sender on the drive, which prevents bringing the drive too far out (up) while operating the boat underway. The Trailer button bypasses the trim limit sender and allows the drive to be brought all the way out. Obvoiusly the trim IN switch brings the drive in (Down) regardless of how far out the drive is.

When the drive is trimmed all the way out via the trailer buton, or all the way in, via the drive trim in button, the pump will make a slightly different (higher pitched noise). I use this to let me know when to stop trimming in or out.

Just to clarify, are you saying the trim pump is, in general, making a louder noise through the entire travel range? Or are you saying that it is much louder when it is all the way in or out? Or are you saying it only makes noise when the trailer button is used rather than the trim in/ou buttons?

shrew is offline   Reply With Quote
Old 09-02-2011, 08:01 PM   #3
Join Date: Apr 2011
Posts: 3

Hi shrew, thanks for the welcome and the reply...

The function and sound of the actual trimming motion (up and down) is fine, including trailering. Once the drive is trimmed all the down/in, it always has made a different noise, as it should while the fluid is continuously flowing through the bypass. It's just that now the bypass sound from the pump is more of a shrieking/higher pitched sound than it ever was before, while trimmed all the way down. Thanks!
willin58 is offline   Reply With Quote
Old 09-03-2011, 03:22 PM   #4

ss3964spd's Avatar
Join Date: Jul 2009
Location: Fairfax Va
Posts: 1,512
Send a message via Yahoo to ss3964spd

Really only one thing it can be, Nick, the pump itself. Of course it could specifically be the bypass or other individual bits inside the pump but I don't know if select parts are available for replacement, or if you simply have to replace the whole thing. either way it doesn't sound too horribly expensive.

ss3964spd is offline   Reply With Quote
Old 09-06-2011, 07:35 PM   #5
Join Date: Apr 2011
Posts: 3

Thanks guys, I'll have to keep an eye on it.
willin58 is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 03:58 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.