my idea for a jet jon build will it work?

thanks ranchero if I see those speeds with a load I'd be more than happy. The guy doing the aluminum welding said he was gonna weld up my hull to make it sturdier I didn't know if that was necessary.

Honestly depending on what he's doing, it shouldn't be. My build started as a 1448mv and has held up fine with just a set of engine mount stringers on top of the ribs from the transom plate to the rib in front of the motor. I also welded an additional 1" x .125" piece of angle to the keel more for the bow extension than the rear.

I will suggest doing some framing up higher when you support your deck. Just understand the forces involved and don't overbuild any one part of it. My stringers are 3/16 and everything else is 1/8" max. The hull is .063, most of the rest is .080 or .100" sheet metal. Check out my build, it's worked very well for the last couple years and the hull is very stiff.

Am I missing a downside to a inboard jet? If I was to buy an outboard jet to get 30-40 mph Id need bigger than a 60/40 which weigh 200-300 pounds and a good used one is 4k plus. So far Im 600 into the motor and parts and probably by the end of welding/ fabrication maybe another 3k into it on the high side and I end up with a lighter faster boat. Are these engines less reliable and more prone to break?

The only downside so far has been picking up trash or maybe the rear deck doghouse. My doghouse isn't huge with the horizontal shaft engine and axial pump. I think a lot of the 'problem' was the original ski power plant was expensive and the Tracker I/B jet was not very popular (again, cost a good bit more vs. an outboard) and the engine did not perform well. The tracker was a vertical shaft centrifugal pump which made it taller and that doghouse was a PITA to fish around.

Picking up trash is just something you have to deal with. A potato chip bag will stop a jet dead if the impeller can't get to it. Weed beds suck at idle but I can blast over them at speed and not pick anything up except water. A short rake or just design your hull so you can reach under the transom and pull the clumps out. O/B jet guys have the same problems only they can tilt the engine up to clear it.

you ever had to pull the pump housing to get anything caught in the impeller or will the impeller spit it out?

On my Boston Whaler Rage, the boat stayed in the water 24 hours a day from March through October and the jet housing started to show the effects of being submerged constantly. I would also get debris in the intake and have to backflush it (turn boat around at the dock and let the river flow back through) but one time a small piece of branch got wedged on the impeller and I had no option but to limp it to the boat ramp a mile away and get it up on the trailer to knock out the debris with a long screwdriver. Never attempt to do that with the boat in the water if you need to go under the boat and hold your breath, that is asking for disaster.

There are only 2 downsides to outboard jets.

1. They cannot be tilted out of the water like an OB jet, and this leaves them susceptible to corrosion/electrolysis. And because they use a water box and wet exhaust system, in cold weather, lines can freeze.

2. They become a vacuum cleaner at idle, and in water shallower than 18-24 inches (or double that depth when in reverse due to the water being shot straight under the boat) your cooling system can get blocked with sand, etc. (Put a Jabsco inline water strainer on your cooling line, along with an OBM water PSI gauge at your dash, and be done with that worry)

As for sucking up leaves, etc....yep, it happens. But if you modify the intake grate into a stomp grate, then, problem solved for that, as well. Check out my Aluma-jet build, near the bottom of page 1, you'll see how to do a stomp grate mod for your pump.

Hope that info helps!

Like this? Thanks for these little tips this is th stuff I need to know.

I've been reading bad things about the cooling system for it anyway to bullet proof it

[url=https://www.tinboats.net/forum/viewtopic.php?p=353965#p353965 said:

amk » Yesterday, 22:53[/url]"]Like this? Thanks for these little tips this is th stuff I need to know.

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Yep, exactly like that. However, I recommend also buying the 3/4" model, and using the strainer screen from that, as it's slightly more coarse. The screen that comes with the 5/8" model is very fine mesh, and actually does too good of a job, and loads up quickly.

Also, as I mentioned, get an outboard water PSI gauge, and install the T fitting between the strainer and the engine. This way, if the strainer clogs, the PSI drops, and you can shut down the engine before it overheats.

That number for dan I called and it says it doesn't except incoming calls or something

Hmmm, that's odd. But then again, he just re-located his shop a month ago, so, that might have something to do with it.

Try his cell (843) 450-9101. I'm pretty sure that number works.

I see alot of guys putting little v shapped wedges before the grate on the bottom is that necessary?

Mine is a rounded V. Technically it should be shaped like a spoon, hence its name, "spoon".

yes but is it necessary

amk said:

yes but is it necessary

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Um, well, that it a hard question to answer. Most of the successful builds I have seen have them. Some try without and depending on hull design it may or may not work, then add it as needed. I built mine while doing the install to avoid grafting it on later.

Necessary? With so many different boat hulls and jet ski pumps being used I believe every install is different, some may benefit from one, some may not.

one of the cylinders isnt holding compression anyone got a 650 short block?

Got the motor rebuilt and found a guy to build the boat since

Coming together nicely

Very nice work on that tunnel modification! Looking good.