Venturi Removal Problem

[Tman240]

I went to change the jet pump oil and ran into a very quick but apparently existing problem.

3 of the Hex screws holding the venturi in place came right out. The 4th one immediately just spun in place and is obviously loose(it can actually move about 1/4" in and out) but beyond that it appears it has no thread engagement to the venturi assy. Clearly this tells me the jet pump oil has not been changed in I don't know how long since I purchased this ski beginning to mid summer. Second, how in the hell can you get the screw out and is there any reasonable fix other than a new venturi assy?

Got to love buying used sometimes...this was definitely a hidden, "I'm not going to mention it" problem.

Tom

[Bill O'Neal2]

Re: Venturi Removal Problem

You might be able to salavage it by installing a Time-Sert into the housing. The oem thread size is 5mm.
If that doesn't work, tap it to 6mm and drill a 6mm hole in the cone for that bolt.

[Tman240]

Re: Venturi Removal Problem

Thanks Bill,

So getting the existing bolt out I assume means drilling it out first correct? Would you recommend cutting the bolt head off and then drilling or ??

Second, is this a common problem given the cone is plastic and I suspect fairly easy to strip the internal threads if over tightened?

Tom

[Tman240]

Re: Venturi Removal Problem

Think I have another question... Getting the drill in place in terms of access looks like it will be a problem with the steering nozzle there. The bolt in question is the lower right hand bolt.

Tom

[Bill O'Neal2]

Re: Venturi Removal Problem

So remove both nozzels.........

[Tman240]

Re: Venturi Removal Problem

Taking the steering nozzle off doesn't appear to be too difficult, but arriving at the venturi assembly with that bolt stuck(apparently it is the threads in the impeller housing that are stripped) is well where I'm stuck.

Drill the existing bolt out head and all? Then try the time-sert?

Sorry for what may seem like idiotic questioning but just want to get the procedure right.

Tom

[jt40]

Re: Venturi Removal Problem

Try grabbing the head of the bolt with needle nose pliers and pull and unscrew at the same time. sometimes it will catch the threads and unscrew

[Bill O'Neal2]

Re: Venturi Removal Problem

Now I'm confused as to which bolt is stripped out. I thought you were saying that one of the tree cone screws was stripped? Or is it one of the 8mm venturi nozzel bolts?

Like he said, if it the venturi nozzel bolt, grab it with vise grips or pliers and pull as you unwind it. If it is the cone bolt, it is probably recessed enough so you cannot grab it, depending upon which year model cone assembly you have.
What year, make and model are we talking about here?

[Bill O'Neal2]

Re: Venturi Removal Problem

Ok, I think I know what your problem is. You have a plastic pump housing assembly.
Behind the ear is a plastic square that holds a 8mm nut. The whole nut assembly is spinning in the holder.

The way to get it apart is to remove the whole pump assembly from the boat. Then you can get hold of it.
I use a sharp chisel to cut away the square plastic surrounding the nut. Then I use a 13mm wrench on the nut to hold it still while I unscrew the venturi nozzel bolt.
This happens alot on those plastic pump housings.
When you finally get to replacing the bolt, put grease on the threads, not loc-tite.

[Tman240]

Re: Venturi Removal Problem

Correct, that would be the bolt(8mm x 70) in question along with the plastic nut housing.

Item #34 and Item #20 at HLSM on-line parts.

Removal of the entire pump assembly, now that sounds a bit much for my liking...but doesn't look like I have much choice.

Any procedure for this you could recommend?

Once I do get this bolt out, I will be sure to use grease. Doesn't make sense to me why the OEM recommends loctite with this sort of plastic application.

Tom

[Bill O'Neal2]

Re: Venturi Removal Problem

Pulling your pump is a very simple operation. Remove everything connected to the nozzels ( that is one screw and one bolt ), then remove the 4 17mm nuts holding the impellor housing to the back of the hull. Remove three hoses from the fittings on the pump which are located inside of the hull.
Grab the nozzels and pull straight back. The pump should come out. Some prying might be necessary as it will be stuck to some silicone sealant.

[Tman240]

Re: Venturi Removal Problem

Okay, thanks. Will give it a go tonight.

What do you think about replacing those square plastic nuts with some bronze? I kind of like the idea of just putting grease on the threads instead of the OEM suggested blue loctite. I understand they don't want the bolts to back out, but I can't see that happening in all reality.

Thanks for the advice.
Tom

[Bill O'Neal2]

Re: Venturi Removal Problem

Bronze is a dissimiliar material from the SS bolt and would probably be even worse when it came time to remove the nozzel bolts again in the future.

If your bolt has come back that 1/4 inch that you were talking about, you can use a hack saw to cut the bolt in half if you put the blade between the venturi nozzel and the impellor housing after you remove the other three bolts. I use a sawzall myself.

[Tman240]

Re: Venturi Removal Problem

Exactly my plan...going to use a dremmel to cut the bolt since I have at least that much bolt exposure to work with.

I should know better on the bronze/SS dissimilar metal....mechanical engineer by degree and now in business development for large power generation projects. Shows you why I'm not a practicing engineer anymore!

Tom

[Tman240]

Re: Venturi Removal Problem

Bill,

Going to attempt to remove the housing tonight. Other than the 3 hoses on the inside...is there coupling securing the impeller shaft or should that just slide right out one I break the silicone seal at the external hull/housing interface.

Tom