Is there such a thing as trim/tilt on a jet?

[Daley]

Got a '97 Sugar Sand Heat with a 120xr, and while I've been around boats a little bit I don't have a clue if it doesn't have a prop. Is there such a thing as trimming on jet-powered machines? The ride-plate (I'm assuming that's what it's called, right behind the grate) appears to be missing two bolts and I'm just curious how much of a difference this makes. Can y'all educate me a little on jet-powered stuff?

 

[thumpar]

Re: Is there such a thing as trim/tilt on a jet?

Any trimming of a jet powered craft would be from the nozzle moving. Some have it some don't. The ride plate should be fixed.

 

[Daley]

Re: Is there such a thing as trim/tilt on a jet?

Duh... Seems like those were some silly questions, now that you've answered 'em for me. I guess I just have to get past the newness of it. Somehow it makes so much more sense AFTER I post the questions for some reason :redface:

Thanks thumpar

 

[haulnazz15]

Re: Is there such a thing as trim/tilt on a jet?

The trim is somewhat of a pointless option on jetskis and they tend to have a lot of issues. VERY expensive to replace, so most people just set them in the lowest position when the trim unit fails. There is some difference, but the amount of time that jet skis spend going from zero to planing speed leaves little time to be messing with trim constantly.

Also, just go to a dealership and order the facotry bolts for the ride plate.

 

[Daley]

Re: Is there such a thing as trim/tilt on a jet?

hmm, let's see... hardware-store bolts for 29 cents and have it NOT be right, run the risk of problems BECAUSE they're not right, and deal with the cost/labor/embarrassment of such, OR, go get the RIGHT bolts the first time for a couple bucks... Yeah, I think that's good advice that I'll follow.

Oh yeah, thanks for helping with the trim question as well

 

[thumpar]

Re: Is there such a thing as trim/tilt on a jet?

I use the trim constantly on my ski and it does make a huge difference. Don't know if it would do as much on a jet boat.

 

[haulnazz15]

Re: Is there such a thing as trim/tilt on a jet?

I use the trim constantly on my ski and it does make a huge difference. Don't know if it would do as much on a jet boat.

It would help MORE on a jet boat than it does on the ski. The bigger the boat, the more bow you can get out of the water thus higher speeds. The jet ski weight and balance points vary so much, especially since most of the fuel/oil is located in the fron half that as you burn fuel, less up trim is needed. You may "use" it constantly, but trim units aren't designed for constant use. They are designed to be used while coming on/off plane and then left alone. Jet skis run stop-n-go so much that the benefit is usually not that great, and when they break from such rapid/constant use it hits your wallet.

 

[thumpar]

Re: Is there such a thing as trim/tilt on a jet?

I guess that makes sense about trimming a boat. That is how I trim my propped boat.

I use the trim on the ski to make it handle different. Point down you can get wet. Point it up and you can get it porpoising like a bull. I have fixed it once for $0 and then water proofed and fixed the weak spots that kawi figured wasn't needed.

 

[H20Rat]

Re: Is there such a thing as trim/tilt on a jet?

Any trimming of a jet powered craft would be from the nozzle moving. Some have it some don't. The ride plate should be fixed.

nope...

The angle of the ride plate will make a HUGE difference in how it handles. In my case with a sport jet 175, the ride plate is adjustable with threaded screws. Turning the screws half a turn makes a noticeable difference in handling, even though the ride plate didn't move any visible amount.

There is a REALLY nice aftermarket electric ride plate out for the 175+ sportjets, just a little $$$ though.
http://www.placediverter.com/index.php?page=mercury



Anyway, back to the original question. No, sportjet 90/120's do not have adjustable ride plates, and there is no aftermarket option to add one. You MIGHT be able to trim the front down a little by getting the screws you are missing, and then slipping some small washers between the ride plate and the pump above. (forgot what the 120 looks like, sold mine last year)

 

[Crater]

Re: Is there such a thing as trim/tilt on a jet?

On my SJ 90 ride plate there are 2 notches near the rear of the plate. By removing the plate and bending the plate down at the notches is the only trim option. Slip washers or spacer between stator and ride plate and replace bolts. Manual say to replace bolts with new ones but not everyone has a dozen extra bolts lying around. Just remember to use Locktite on them, alot of viberation down there will loosen them up fast.
BTY this adjustment is to counter porpusing affects not really to trim the boat.

 

[Daley]

Re: Is there such a thing as trim/tilt on a jet?

Thanks for all the replies! My ride plate is missing two bolts in the rear, and there appears to be about a quarter inch of space between the plate and the stator, so I'm guessing that just tightening it up will change it some - how much is yet to be determined. Judging from some good information above, it appears that I'll notice quite a bit with a full quarter inch!

Now my gears are turning trying to come up with a way to make that remotely adjustable, but I'm not coming up with a safe way to do that. It wasn't engineered that way so I should leave well enough alone, right? If only my mind worked that way

Regardless, again - I appreciate the wealth of info that everyone has shared.

 

[Crater]

Re: Is there such a thing as trim/tilt on a jet?

Yep, use washers to space the ride plate down then replace bolts USE LOCKTITE on these I've had a couple fall out from the vibs, and your good to go.