Prop shaft vs crankshaft alignment on DPS-A

[saaristo]

My boat has always had this bow-high riding attitude. So much so that it is often porpoising unless the tabs are down. Other boaters are saying why don't you trim down your outdrive, but it is as down as it can be. So when doing maintenance I adjusted the trailer so that engine is level on longitudinal axis (crankshaft is level). And then found out that even when fully trimmed down the cavitation plate still points upward, not much, but still. So I'm wondering, 4.3 gxi +DPS when trim is "zero" should the axles be parrallel? When trimmed down to -6 shoul the angle be negative i.e cavitation plate pointing downwards?

 

[saaristo]

Decided to update the first post with some clarification. Accordiing to manual the -6 to +6 is the normal operating trim range (respective numbers on EVC screen). On the drawing (a real work of art, I know) - is it so that when EVC shows me "0" it means the engine crankshaft A and the prop shaft B should be parallel? Similarly, if EVC shows me -6 the prop shaft should be looking down and when +6 then looking up compared to axle "A"?
If that's the case then something is really wrong - even when trimmed as down as it can be the prop shaft is looking up. The only thing that seems to limit it from going further down is that the trim cylinders won't retract more (leaving like 2 inches of piston visible between cylinder end and piston eye). How do you adjust that?

 

[BRICH1260]

If your trim rams are showing two inches of ram showing then something is definitely wrong, mine retract to the hilt. You have something out of place within your rams preventing it from complete retraction. You may need to disable them to see what the problem is. It may be a limiting spacer placed on the wrong side of the piston.

 

[saaristo]

This is how the piston is visible when fully retracted (EVC shows -6).

 

[BRICH1260]

I`ll take a look at mine tonight and compare. I just know when mine is fully down, there is a negative cant to the propeller line.

 

[dan02gt]

This is how the piston is visible when fully retracted (EVC shows -6).

While I don’t have measurements the trim rams in my SX-A drive retract further than that significantly. You could remove the pins that hold the ram to the drive, lift the rams out of the way, and see how much further the drive will go down without them connected. Something is definitely up with your setup.

 

[saaristo]

Did some experimenting and now I'm really confused. Since I was about to rebuild the cylinders anyway , I drained the cylinders. And now all of a sudden there seems to be nothing physical that would keep the cylinders from retracting to the end. And now also the cavitation plate is pointing down. I don't get it, was it all wrong trim sender adjustment which didn't allow the cylinders to retract more? To my understanding the sender/gauge should not restrict the pump from pumping it all the way down, but rather it would have to be a physical limiter?
Now, when trying to put it together again, is it so that when trim gauge shows zero the cavitation plate should be parallel to the keel? And when cylinders fully retracted the gauge should read -6 (meaning the cylinders are bottomed out)?

 

[dan02gt]

Did some experimenting and now I'm really confused. Since I was about to rebuild the cylinders anyway , I drained the cylinders. And now all of a sudden there seems to be nothing physical that would keep the cylinders from retracting to the end. And now also the cavitation plate is pointing down. I don't get it, was it all wrong trim sender adjustment which didn't allow the cylinders to retract more? To my understanding the sender/gauge should not restrict the pump from pumping it all the way down, but rather it would have to be a physical limiter?
Now, when trying to put it together again, is it so that when trim gauge shows zero the cavitation plate should be parallel to the keel? And when cylinders fully retracted the gauge should read -6 (meaning the cylinders are bottomed out)?

In that picture yours looks like mine does when it’s all the way down. I agree on the trim position sensor and don’t think it has anything to do with how far the drive will go down.
On mine when the drive is al the way down the gauge shows all the way down. I have no 0 or -6 on my gauge dashes for increments.
I wonder if something is going on with your pump.