# Convert Yamaha F25 to jet drive



## knot_trying (Oct 28, 2020)

Getting really tired of all the rocks and trees with my Tohatsu 20 on my Towee.

Thinking about trying to find a new Yamaha 25 and then getting the jet drive from Outboard Jets.

Curious to know if that's a fools errand or perhaps not a bad idea? Also wonder how long it would take to switch back to the prop drive lower unit if I want to hit the lake?

Figure I would end up with about 18HP at the jet drive which I can live with as I don't need speed but peace of mind while running the Hooch.


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## Smackdaddy53 (Dec 31, 2012)

Call Outboard Jets and discuss with them your hull etc and they will line you out.
I do know to go jet you need the absolute lightest hull possible due to the inefficiency of the jet lower unit. I had one and sold it after a month once I realized I needed a much larger outboard to get the performance I wanted. At that point I just went prop.
There’s a boat builder here in Tejas called Black Duck Skiffs that is all about jets so you might get some good conversation if you call them up.






Black Duck Skiffs | Shallow Water Performance and Durability.







blackduckskiffs.com


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## Bending.banjo (Dec 19, 2021)

Following... Have one of the new F25s and considering the same idea for a 14ft Jon for river running.


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## Wolfmansbrother (Mar 4, 2021)

I can’t say for sure as I’ve never used a jet that in that hp range but I’ve switched a 2 stroke 70 hp yammy to a jet and I wasn’t honestly not all that impressed with the result. It does serve its purpose in running shallow but the loss of power makes it almost not worth it. Motor sits on a 1652 all welded boat end tops out around 18 mph with three men and fishing gear. Same set up ran 35 mph before the conversion


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## rickc (Nov 7, 2018)

Rule of thumb Is you need about 1.5 times the horsepower when switching to a jet. A 40 hp outboard jet will probably get you where this 25 now performs 

Grass is hard on jets too. They clog up pretty easily


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## Hank (Jan 14, 2019)

Switching lower units back and forth probably won’t be worthwhile. The motor won’t be at the right height for one or the other set up and the jet really needs to be right to get good performance.

For a light boat and one person I think adding the jet to a 25 will be slow but OK. Any more than that and not so much. The boat weight chart at outboard jets seems correct - have a look at it.

FWIW, my 400lb. 1652 with one person and a Yamaha 30/40 jet runs 25-27 mph. Plenty fast for small rivers or really anywhere unless you have to make long runs. But you might want a bigger boat for that anyway.

20mph will get you 5 miles upriver In 15 minutes. That’s a good bit of fishing as you drift back down. If you feel the need to blast from spot to spot at high speed you may not like a slow boat. But that 20’ bass boat with a 250 on the back that will run 70mph will really suck if you get it stuck on a gravel bar or try to maneuver in 6” of water on a 70’ wide river.

For the correctly defined use a small light boat with jet can be the answer.


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