(not so) Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

[Ahhk]

Hi all!

I have a 1998 Stingray/4.3L Mercruiser-Alpha1 and am having a issue with the drive tilt/trim.

The short version is that it will go down properly....but will only go up (via the U/D) switch about 1/4 the way.

The odd part (at least to me) is that the drive goes up fine with the "Trailer" button on the throttle control.

If it didnt go up at all, I think there would be some obvious things to check. But the fact that it goes up part of the way with the U/D switch and all the way with the Trailer button.....confuses me.

Going up with the Trailer button suggests to me that its not a hydraulic/fluid/air in the line issue.

Going part of the way up via the U/D control suggests to me that its not an electrical issue.

Anyone have any idea what I am missing here and might need to check?

How would the "up" signal/voltage/polarity from the U/D control be any different than that from the Trailer button?

Thanks for any help!

 

[frank246]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

This is correct.
The u/d switch is to "trim" the outdrive, but it is limmited by a limmit switch on the port side of the gimball housing. The tilt (trailer) function overrules (by-passes) the limmit switch so the drive moves up complete.

 

[Ahhk]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Oh...........

Yeah, now that makes sense!

So, I guess I need to adjust the limit switch (if its adjustable)?

Or is the trim SUPPOSED to be limited to going barely 1/4 the way up? Heck...its probably closer to 1/8 (like the skeg moves maybe 4 - 5 inches) ). Seems odd to have to use the Trailer tilt when going in to shallow water.


Thanks for the response. I always assumed the "limiting" was mechanical.

 

[Don S]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

The trim is limited to a certain distance of travel. You should have another button on your control that operates the trailer (full tilt up) position. If you can't find it, post a picture of your throttle and shifter. I'm sure someone can show you where it's at.

EDIT: Nevermind, just re read your post.

 

[haulnazz15]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Well, the point of the trim limit switch is to KEEP you from tilting the drive up too much which can bind up the u-joints between the drive and the engine. Ig you are talking about going into 2-3 foot of water, I would be very careful about having the trim above where the trim limit stops. You can adjust the trim limit switch, but unless you're sure it isn't allowing the drive to go up the correct amount, I wouldn't mess with it. Remember, you don't want to have the engine above idle rpms when above the trim limit.

 

[Ahhk]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

The trim is limited to a certain distance of travel. You should have another button on your control that operates the trailer (full tilt up) position. If you can't find it, post a picture of your throttle and shifter. I'm sure someone can show you where it's at.

Don,

Thanks, per frank246's comments I understand that the up trim is limited by a switch. What I was asking in my followup was whether <10 degrees/4 - 5 inches of skeg movement was a normal amount of trim (up) movement.

Thanks for the responses!!

 

[Ahhk]

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Re: Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Well, the point of the trim limit switch is to KEEP you from tilting the drive up too much which can bind up the u-joints between the drive and the engine. Ig you are talking about going into 2-3 foot of water, I would be very careful about having the trim above where the trim limit stops. You can adjust the trim limit switch, but unless you're sure it isn't allowing the drive to go up the correct amount, I wouldn't mess with it. Remember, you don't want to have the engine above idle rpms when above the trim limit.

Gotcha! Guess I'm just used to outboards - where as long as the water intake is in the water...its all good!

When I refer to the shallow water, Im not talking about going full throttle across some flats but rather maneuvering up to the very long/shallow concrete boat ramp and being nervous about striking it with the expensive 4-blade SS prop :0

 

[Bronc Rider]

Re: (not so) Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

You are not supposed to rev the engine above 1200 rpm's when the drive is higher than the trim limit allows. Also, if you look at the drive you will notice it has two "ears" (gimbal flanges?), one on each side of the drive. These give the drive side to side support while turning. When the drive is too high up, those flanges do not make contact with the drive.
I avoid my I/O when going fishing because its shallow where I go too. I used to jump out and push the boat where I wanted it when I reached shallow water. Now I own an old outboard powered whaler just for fishing. I still use my merc powered bowrider 80% of the time though. Sterndrive powered boats are just not very friendly with skinny water.

 

[Ahhk]

Re: (not so) Odd Mercruiser 4.3/Alpha 1 Hydraulic Drive Lift Issue

Thanks all!

Ive previously always had outboards and wasnt aware of the I/O u-joint issues with the trim and will be sure to keep the RPMs low when trimmed up.

I dont intentionally go in shallow water - it's just unavoidable with the boat ramp I use. I've only done slow/short maneuvering moves while trying to sync up with the trailer....with a cross current.

Learn something new every day

Appreciate all the feedback!