2020 189 trx 150 pro xs question

[Leeadam71]

When I am on plane and I bump it up to full trim at some point the boat will jerk/slide to one side, not a lot but you can definitely feel it, the sound of the motor changes a little also. It will do this once or twice and then it wont happen again till I trim the motor back down again and the bring it back up. Any ideas what could cause this. Unsure if prop issue 21 tempest, jack plate needs to go up or down or something else.

I dont notice an rpm spike when it happens. But it happens fast.

[Riccochet]

My 18XS has done the same exact thing since day 1. I have no idea what causes it, and no amount of adjusting resolves it. I think it's just a characteristic of the hull design when it gets on pad.

[greenheadz]

intresting... my 18xs has never done that but my cougar FTD did it bad! It would scare the crap out of me!

[Leeadam71]

Yea, it definitely catches you off guard. If it's normal, ok annoying, but no big deal. Just trying to make sure there isn't a bigger issue.

[Riccochet]

It's almost like there is a cavitation pocket on one side of the lower unit that suddenly collapses. Usually around 50 MPH. Over trimming exaggerates it.

Some days I can run all day and it never happens. Other times I think I'm just over trimming too soon and she'll slide to the left a bit.

[bman5150]

Can’t say I ever experienced this but maybe I’m not understanding what it is exactly your boat is doing. What do you mean by “full trim”? As high as it will go under speed? I can’t and don’t go that high because on my boat, I’d be losing speed.

[Leeadam71]

Riccochet nailed it. That is exactly the same symptom. For my boat that little nudge to full trim is worth about 3mph.

[Riccochet]

Can’t say I ever experienced this but maybe I’m not understanding what it is exactly your boat is doing. What do you mean by “full trim”? As high as it will go under speed? I can’t and don’t go that high because on my boat, I’d be losing speed.

Picture this. You punch it and start accelerating while trimming up at the same time. As the bow starts coming up and you hit about 50 MPH the rear/stern of the boat will kick out to the port/passenger side about 4-6 inches. And that's it. It's an abrupt little kick. Smooth sailing after that.

I have checked every nut, bolt, fitting, bled the steering, sent the prop off to Croxton, adjusted the jack plate up, down, yelled at the thing. You name it. She kicks out the left and that's all there is to it.

And Leeadam71 was spot on. The motor sounds like it frees up. Like something was just barely holding it back a little. It's weird. I'll try to get it on gopro.

[chatabass]

I would say it's caused by the prop. I see you sent the prop to be checked out, have you tried a different prop?

[bman5150]

Hmmm. I’ll pay more attention the next time I’m out but I’m pretty sure I’m not experiencing that at all. I do not have a jack plate and run a Tempest 23P with my 175 ProXS. I wouldnt thing the different motor would matter though. Same footprint/size and displacement as the 150 you guys are running.

I notice a change to the sound and speed though when the boat starts to run solely on the pad. It doesn’t jump left or right though. You can just feel the boat lift the front half of the hull above the water line. But I doubt that’s what you guys are experiencing as we all know what that feels like.

[bman5150]

Also wondering what if anything is attached below the water line to your hulls? Any transducers? Anything dragging from the stern while running? Just a thought.

[Jimmy3]

My 2018, 189 TRX does the same thing when it gets on pad. It'll hook to the left. When it comes off pad It'll hook to the right, sometimes that one will scare me when I'm not expecting it.

[Leeadam71]

Ok, it seems like a some what common deal. Makes me feel better. I lowered my motor a 1/4 inch on the jack plate and I am going to run again and see if it is any better or worse. I have noticed if I will run 50 to 53 my boat is smooth as silk, when I push it up to 55 to 56 is when this deal happens. But again happens once then back to smooth. I have been wondering if going to a 22 pitch prop might also help, but I really am just guessing here.

[bman5150]

Almost forgot to mention this - The only time my boat’s rear end gets a little loose is when I run a 4-blade trophy prop. The four blade lifts the stern better than the three blade Tempest so it will get a little loose if I don’t trim down enough in even the slightest of turns. The 4 blade also likes less trim than the three blade. Runs completely fine if I don’t over trim and trim down more than with the three blade in all turns.

the sensation I’ve experienced with that 4 blade sounds similar to what you guys are describing.

[greenheadz]

I honestly believe this happens from over trimming to quick especially in slick water conditions. When there is a slight chop I bet you don't notice it as bad? Mine would do it right around the same speed each time but not every time.

[Leeadam71]

I haven't tried a different prop. Only thing on my boat is a keel guard. I took the boat out tonight, I dropped the motor to 4.25 ptp and it still did it. Was just an idea. Ironically I didnt notice any real performance difference at 4.25, my boat seems to like to run 54 to 56, no matter how I adjust motor on jack plate. I have noticed that if I run wot and set the trim to run about 52 and I am around 5800 rpm it doesnt seem to do it. It's that extra little trim that makes it slide, but then it reaches full speed.

Those of you with jack plates and the 150 pro xs (4 stroke) what prop and what's your ptp, if you know.

[Leeadam71]

I like the idea of mounting a camera back there pointed at the motor and see if I can catch a video of it. I will try that this weekend. Home lake is Guntersville, and they are having bass master elite, so I will wait till Sunday to try that.

[chatabass]

The only reason I said it might be the prop was a few years back I had a trx 179 that would back end shift every once in a while when trimmed up and full speed. It wasn't severe enough to cause me concern and I never mentioned it. Another guy on here had the same boat and IM'ed me asking if mine did this because he apparently had one that did this worse than mine (mine was quick shift and done) his was bad/often enough it caused him concern. He changed props and it stoped.

[Bob20]

My TR186 did that nearly every time at around 45 mph. The rear end would kick out suddenly and scare the shit out of me! Always worried the bow would hook on me. My motor(150 Opti with 21Tempest)) was about 4" below pad. Raised motor to 3.25 below pad and it helped quite a bit. Then switched to 23 Tempest and no more problems!
I know that sudden"kickout" scared me!! Mine was pretty bad and a little too violent for me! Never had that happen on a boat before.

[bman5150]

Went out today and did not notice anything like what’s described in this thread. Maybe a different prop would be worth a shot.