Flat bottom jet

[Fishinglohr]

I have a flat bottom 16 foot 60 inch wide jon boat I'm putting my yamaha 700 in, I was wondering if there is anything besides a spoon to help stop cavitation? I had a spoon on my 1536 jon boat and I didn't have any issues but it was a modified v and this one is completely flat. Thanks

 

[amk]

don't worry about a spoon until your sure you need one if the intake is flat with the bottom you shouldn't need one. I had someone say my boat wouldn't work it would cavitate blah blah blah... it works just fine doesn't even have a loader grate no cavitation and no spoon.

 

[amk]

what year is your motor? Are you sure its not a 701?

 

[Fishinglohr]

I'm not sure of the year, it was out of a waverunner3. It had plenty of get up and go in the old boat but I'm not sure how it's gonna do with this boat. I'm already looking for a 1200 yamaha.

 

[amk]

ya a 1200 would be a bad mama I have a 1648 and I just put a 760 in it. A 701 is it dual carb or single? youll go about 30 more like 28 with your set up would be my guess.

 

[CedarRiverScooter]

I would install the jet ski hull as deep as you can. Use as much length of the hull (to capture the keel) as you can. I am having to screw around with modifications to get rid of cavitation. I am convined that a deeper intake would have prevented my cavitation issue. Just my opinion. Others will differ I am sure.

 

[ColtonS]

It really all depends on how you plan to do the modifications (fabricate/weld or slice/splice) and the type of water you will be running it on.

 

[Fishinglohr]

It's a single carb 701, it's gonna be used in the upper potomac for fishing, I'm gonna bolt and weld the pump in

 

[ColtonS]

I'm not familiar with the potomac river but if it's shallow/rocky and you run high risk of finding the bottom then your options are limited. If its a fairly deep river and low risk of impact then your have a few different directions you can go. The condition of the surface of the water (smooth, choppy, rippled, ect....) will also be a factor to account for.

 

[BigTerp]

I'm not familiar with the potomac river but if it's shallow/rocky and you run high risk of finding the bottom then your options are limited. If its a fairly deep river and low risk of impact then your have a few different directions you can go. The condition of the surface of the water (smooth, choppy, rippled, ect....) will also be a factor to account for.

This is what can happen on the Upper Potomac.

Busted drain

Hole ripped in hull

Jet foot implosion

 

[Ranchero50]

It's a single carb 701, it's gonna be used in the upper potomac for fishing, I'm gonna bolt and weld the pump in

I'm in Hagerstown. If you want to check out my boat let me know. I have a 3` dead rise and still ingest some air in heavier chop where white caps show.

To me a jet boat just means you can idle through areas as deep as your hull is. I have too much time in my hull to be running WOT through too shallow areas.

 

[bnt5]

I have the same boat you are going to use, it is a 16' flat bottom jon with a wide bottom. I installed a 750 Kawasaki engine in it and dropped the intake down about 2" which kind of created a spoon of sorts. I can run no problems in the rivers around here and have some slight cavitation in fast riffles and choppy water, if I go out on a big lake and it gets windy then I am basically just idling along due to cavitation. The flat bottom does fine for what I need it for, I can run in crazy skinny water on step and never touch bottom, it's not an ideal hull but it works. My next one will be a modified Vee welded hull with a good deadrise to help push those choppy waves aside and not straight into the intake. But I love my jet boat flat bottom or not. :mrgreen: