Possible Inboard Motor/Pump

[catmansteve]

So my friend's father has a small fiberglass jet boat that he wants to get rid of, and I'm curious to know if anyone here has ever heard of the boat/motor or considered using the combo for an inboard jet jon. The boat is a 1988 Jetstar 1250, 12.5' fiberglass 3-seater speed/ski boat. From what I can find it was made by the Ultranautics company, they also made a Wetbike and a conventional PWC with the same engine/pump. The hull is in rough shape and leaky, but the boat is all together and runs fine aside from the leaks, and I can buy the thing for a song basically.

Now the interesting part: the engine/pump combo is similar in design to a Mercury Sport Jet. It uses a verticle shaft Suzuki 50 hp outboard powerhead that sits on top of an aluminum intake/pump. I've ridden in the boat before, it runs about 30-35 mph with two people, and according to the spec sheet the dry weight of the boat is 700lbs, the motor itself weighs about 150lbs. I'm going to guesstimate the dimensions of the engine compartment to be 30" long by 18" wide by 24" high. I'm thinking the motor would be perfect for a medium sized jet-jon fishing rig, either a 1448 or 1648 hull, and would have a much smaller footprint as well as a more straightforward fabrication than a jet ski motor/pump.

Does anyone have any knowledge or experience with these boats or motors? Anyone ever heard of this engine/pump being used for a jet jon?

 

[catmansteve]

Just found this youtube video, no idea who's video it is but the boat is basically identical to this
https://www.youtube.com/watch?v=I0cHvrA8Ou4

 

[openseat]

I considered doing this a couple years ago, for all the reasons that you mentioned. What put me off was it looked like parts availability was pretty limited. 1991 was Ultranautics last year. Seems the wetbike collectors around here snap up junk just to scavenge what they can. I haven't come across another make besides ultranautics where that suzuki combo was used.

There is a guy in WI that apparently bought out some remaining warehouse stock of ultranautics parts. Google deckjetwatercraft. I would check with him about it will take to replace wear items like the impellar.

 

[catmansteve]

Yeah, locating parts is definitely a concern. I checked out that site, seems he has just about everything for them, thanks for the link. I think I'm going to go ahead and buy the boat, the trailer is worth more than his asking price, and just hold onto the motor until I can find a hull I'm willing to chop up.

When you were researching the motor did you find out anything about the thickness/durabilty of the impellor and pump? I know that's one of the biggest complaints against jet ski pumps in river boats, they're not heavy enough to handle picking up sand and gravel.

 

[openseat]

I don't have any pump specs. IMO a critical issue with pwc pumps is choosing a model that has a wear ring or replacable liner. Otherwise, you have to replace the entire pump housing if the pebbles/sand beat it up.

If this model has a wear ring or liner, there should be somebody selling them. Or, look for a parts diagram/owners manual.

 

[PSG-1]

I don't have any pump specs. IMO a critical issue with pwc pumps is choosing a model that has a wear ring or replacable liner. Otherwise, you have to replace the entire pump housing if the pebbles/sand beat it up.

Absolutely right! Most PWC's have the wear ring as an individual part than can be replaced. Some, however, such as the Kawasaki 750, the entire pump is one unit, and if the wear ring gets chewed up, you have to replace the whole pump, which is about a thousand dollars for a newly manufactured one, and about 500 for a used one. As opposed to the wear ring assembly for a Yamaha XL1200, which is about 150 dollars.

Also, it should be noted that some PWC's like Sea Doo use a replaceable wear ring liner made from plastic, which keeps you from having to replace the entire wear ring unit. Also because with stainless wear ring liners, what often happens is salt water getting between the aluminum wear ring housing and the stainless liner, and causing a bulge. This bulge swells up a high spot on the wear ring, and the edges of the prop bind against it, or hit it while spinning, wearing down the prop.

With a plastic liner, the dis-similar metal factor is eliminated, as is the wear on the prop caused by the swelling of the wear ring. In theory it's a good idea, but in practical use, it's like having a plastic propellor on a boat.

As long as you're running in clean water, it'll run a long time with no issues. But the first time it sees sand or gravel, peace out....you'll be replacing it. As opposed to a wear ring with a stainless liner, you can run those through a little sand and it won't kill them.

Just my .02 as someone who's seen results of various jet skis run in sand, salt, and silt.

 

[catmansteve]

Thanks guys. The boat owner (my buddy's dad) has all the original paperwork, owner's manuals, parts diagrams, you name it, so I'll check and make sure it has a replaceable liner, I think it does but I'm not positive. I've been weighing the options for a few days, and I think I'm gonna go ahead and buy the boat, even if I decide not to go through with the build I can still probably double my money by parting the thing out.