Baffled

[rock54]

First post here. Have a 04 Utopia 185 with the 240. Im new to boats, especially the jet boat. Took it out for the first time this year and got floating in rather shallow water while fishing. Fired it up and took off, when loud knocking sounded and boat shut off. Wouldn't start. Looked at engine and watched starter kicking out but failing to turn over motor. Thought oh no I blew it up. Was able to turn flywheel by hand. So tried to fire up. It started, so accelerated and it quit immediately. Now I can't turn motor at all. Pulled it out of water to see if I sucked something up. Took grate off and holy sh*t rocks fall out. Huge rocks!! Look at impeller and found rocks stuck. CAN SOMEONE PLEASE TELL ME HOW ROCKS THIS BIG GOT SUCKED UP! Impossible , right?!! Check out pics.

 

[Lumps]

its crazy those got past your grate. were you able to get everything sorted?

 

[rock54]

No I haven't. Going up to camp in morning to get into it. There is no way a rock 4 inches in diameter can squeeze through a grate with approx 1 inch gaps. Is there another way?? IDK. Im starting to get paranoid thoughts, like the shop that winterized it, placed them there to F up my boat....so I have to take it in for 3000 worth of work. Like I said I'm dumb when it comes to boats.....don't know how they would get there.

 

[Lumps]

mine has the grate that is on a spring. not sure the purpose but it hinges inwards on a leaf spring. I don't think mine would hinge enough to let a 4 inch rock through but it definitely would let rocks in that are larger then the gaps in the tines.

I guess the question is what is the purpose of a grate that still lets in rocks? anyway, there are a couple of options for fixed grates that people usually get since the version I have has a history of having the spring break and go through the prop. there is a rock version and a normal one with wider tines. worth while looking at the rock one since it seems like you are in a rocky area

 

[Lumps]

No I haven't. Going up to camp in morning to get into it. There is no way a rock 4 inches in diameter can squeeze through a grate with approx 1 inch gaps. Is there another way?? IDK. Im starting to get paranoid thoughts, like the shop that winterized it, placed them there to F up my boat....so I have to take it in for 3000 worth of work. Like I said I'm dumb when it comes to boats.....don't know how they would get there.

also, there is a great pdf that shows you what you need to do call sjannualservicev1.1_190.pdf. just google it. its out there in a number of places. its not as simple as removing 4 bolts but its doable. just be careful of breaking off bolts. make sure you do the part about using penetrating oil a few days in advance. you may even choose to doa that part a number of times if you are in salt water

 

[henryb]

If you have the Hydro-surge grate, and the Spring that holds it closed is weak or broken... then it is possible to suck up rocks of that size... I've done it myself. So once you get all of the rocks removed, then I would order a "Rock Grate" (which is still available from Mercury and replace the Hydro-surge.

The Hydro-Surge grate (sometimes called the Weed grate) is designed with the splines on a hinge. The splines are supposed to be held down in a closed resting position with a metal finger type spring... to keep debris out at low speed. But once you are up on plane and engine revving higher, it will open up to allow weeds and other soft debris to be chopped up by the impeller. But once they get old, the spring that holds the splines down gets weak or a few of the fingers break off... the the splines can open even at idle and if you are in shallow water, you could suck up rocks.

 

[henryb]

The Rock grate is fantastic in that it has 11 thin splines, instead of 6 thicker splines. It is not mounted on a hinge, it is fixed in place.

It will definitely keep those rocks out... but it does have one down side, is that if you ride in weedy areas, it does get clogged up with weeds a bit easier... thus requiring you to jump in the lake and clearing the weeds off... which is normally a very easy task typically one minute and it's clear... but I always leave in the boat: a divers mask, bathing suit, towel, and even a wetsuit for those chilly days... just in case!

 

[rock54]

Ahhhhh! So that's how. I didn't realise that was on a spring like that. Thought it was fixed. I will definitely pursue a rock grate.
Any tips on how to get rocks out without having to pull stator? And thanks for your responses.

 

[henryb]

There's no magic trick... I would start by pulling the Hydro-surge grate off... it's held in place by 4 screws... so make sure you approach this job with the right tools, as they are known for breaking off. Speaking from experience... my Rock Grate is being held on with only 3 Screws at the moment!

Once the grate is off, you should be able to free up most of the rocks and any other debris from underneath. Then you can get a better look to see if the impeller is damaged or not. Check to see if the Blades of the impeller is bent or badly dinged... if not, then check the gap between the outer edge of the impeller blades and the wall. The gap should be fairly tight, like 2 sheets of paper, if it's more like the thickness of a quarter, then that's too much and will need repair. More then likely yours is probably somewhere in between and you will just need to determine if your boats performance is adequate or not...

What is adequate? Normally (with 1 person onboard and half a tank of gas) your boat should get up on plane in about 3 seconds from idle to full throttle. It should run about 50mph at full clip. These are just rough guidelines mind you. There are many other factors that could weigh into the equation as well.

 

[henryb]

I took a closer look at the photos you provided earlier... and from what I can see, the impeller looks ok... but certainly worth double checking all Blades for any dings or damage.

 

[Lumps]

Listen to Henry!!! be very careful of the bolts on the grate. the 2 smaller ones are through holes you can spray penetrating oil on the top side and let it sit in the empty part of the thread above the bolt. the bigger of the two appear to be closed on the top side so getting oil to penetrate is not that easy. if you think they are not going budge doing force them too much. use some heat. I used a small butane torch to release mine (of course after they were already broken off). maybe yours is fresh water only and will not be a sticky. take your time either way

 

[henryb]

As I look back to your original post... it seems that you have already pulled your Grate off!!! So... well done if you got it off without breaking any bolts! I recommend when you put the new Rock Grate on, you get new bolts from Mercury and apply some anti-seize compound on the threads to make sure they won't lock up in there in the future.

 

[rock54]

Awesome. Thanks so much for the knowledge!