Jet newbie question on prop to jet conversion

Good evening all, I have an older riveted Generation lll 1648 with a 2005 Nissan 30 four stroke with power tilt and trim. Currently it is setup as a prop and runs my boat fairly well. Even being it has the older 1.9 gear ratio lower unit instead of the updated 2. Something. I hit 29 mph when trimmed out at full throttle. This is by myself, full fishing gear, decks, 24v trolling motor with two series 27 batteries mounted up front and other misc gear.

So here is the big question. Does anyone have any experience with a similar setup only with a pump? Trying to figure out if switching to a pump would be a waste of money or not. I fish a lot of small and large rivers now and cannot get where others can. Most of the time it's the better of the spots I cannot get into.

The boat is very wel balanced the way I have it setup and I feel the PTT would only help me with being slightly under powered.

Pics are so everyone can see the setup. The motor on the boat then was my old 25 merc two stroke.

I have a 2-st 40/30 on a 16 foot welded jon and I max out at about 39km/h which is around 24mph. I would think you'd be pretty underpowered converting your 30 to a jet.

Bowhunter1661 said:

Good evening all, I have an older riveted Generation lll 1648 with a 2005 Nissan 30 four stroke with power tilt and trim. Currently it is setup as a prop and runs my boat fairly well. Even being it has the older 1.9 gear ratio lower unit instead of the updated 2. Something. I hit 29 mph when trimmed out at full throttle. This is by myself, full fishing gear, decks, 24v trolling motor with two series 27 batteries mounted up front and other misc gear.

So here is the big question. Does anyone have any experience with a similar setup only with a pump? Trying to figure out if switching to a pump would be a waste of money or not. I fish a lot of small and large rivers now and cannot get where others can. Most of the time it's the better of the spots I cannot get into.

The boat is very wel balanced the way I have it setup and I feel the PTT would only help me with being slightly under powered.

Pics are so everyone can see the setup. The motor on the boat then was my old 25 merc two stroke.

Click to expand...

Personally I think if you converted that motor to a jet, you would not be pleased with performance. That would cut the hp down to like 18-20 at the jet. If you are set at getting into the shallower water, I would look at trading/selling to get at least a 40 hp motor which would give it around 28hp at the jet. You have some weight with that 24v trolling motor and batteries alone. When you own a jet you are always looking at ways to cut weight so you can get all the speed you can but most important I think is to get up on plane so u can run shallow. I run 12 volt to save weight. If you're up on plane trimmed you can run in some real shallow water. I just purchased my 4th jet and my second 60/40 mercury four stroke. It's on a 1852. By myself fishing with all my crap, my last one would hit 33 downstream and 30-31 upstream. Only had my new boat in the water twice now and had people with me, it hit 27 with one other guy and crap load of gear at the lake. It's setup just like my last one which was a 2015 model. I not an expert at all, just my experience. Hope this has helped and maybe others will chime in but I just don't think you will get the performance you want or need by converting. Good luck !!!


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Those answers were sort of my fear. My boat has a 35 hp limit so at the time the 30 4 stroke was perfect for me. I bought it at a fairly good price from a buddy and he also threw in a CMC jack plate for it as well, which I never installed because it is massive and rated up to 150 hp. $1700 for everything I don't think is terrible. Just hate to trade it off or sell after just buying it this past summer. I may just continue to putt putt up stream tilted up as high as possible.

I am jealous seeing you fellas crushing through 3-5" of water. Jets are very uncommon up here in N IL. I know of one guy that fishes the same river as I. I speak to him quite often when we cross paths. Funny thing is he putts around the river too, never once seen him on plane in or near shallow water.

As for the trolling motor, I know 24v may seem too much. I just prefer to be able to swiftly move upstream without completely draining a 12v in a shore time. Mainly though I'll drive upstream then float back and use the trolling motor for boat control.

I am hoping someone else may be able to give me some input as well. I greatly appreciate you fellas that took the time to reply!

Estimate your total boat weight as it will be when you are fishing and use this chart from the OBJ brochure to see what your HP requirements are. This chart is based on the prop HP. As you can see. a 30 HP motor would require that the max boat weight be around 900 lbs. Achieving that weight with a 1648 boat (even a riveted boat) would be quite difficult. Also, there is the cost of the jet kit to consider. A new kit would cost you around $1700. I'll have to go along with the other posters. Your boat will be underpowered if you convert to a jet and you will disappointed with the performance. There is also the very real possibly that you will remove the jet sooner or later and be stuck with it or have to practically give it away if you try to sell it. I seriously doubt that there is much of a market for a jet lower for a motor that small.

Here's what I would do in your position.https://propsavers.com/river-runner/ And, save on gas!!!!!!!

If you want a jet go with a minimum 40/30 you will be disappointed converting the 30. As long as you have good strong transom that can take the little extra who cares what it's rated for unless old mr green jeans in your area makes a big deal of it. If you put that jack plate on you could raise the engine straight up to putt putt into shallows rather than trimming up which pushes the back end down when under way. I'd just try mounting that jack plate up and see how you like that before selling off and converting to a jet.