# 40hp Yamaha Jet drive



## Smackdaddy53 (Dec 31, 2012)

They have a flush hose on the foot that feeds water straight to the water pump. I had a jet once and it was a pain in the ass.


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## JC Designs (Apr 5, 2020)

You’ll need one of these to flush the motor. There is a plug right at the grease hose. Unscrew the plug and thread in this adaptor.


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## Hogprint (Feb 23, 2020)

Thanks Smackdaddy and JC D. 

HEY Smackdaddy, can you elaborate a little more on why you didn’t like it? I’ve heard you lose about 10hp by not having a prop. That’s not necessarily a deal breaker for me as it would only be myself an an 11yr old w minimal gear but would love to hear your views on it.


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## State fish rob (Jan 25, 2017)

Not sure about the 10 hp , always heard its closer to 30%. Guys I know with them run the Dan & Roanoke rivers ,chasing stripers


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## Seymour fish (May 13, 2018)

Hogprint said:


> Thanks Smackdaddy and JC D.
> 
> HEY Smackdaddy, can you elaborate a little more on why you didn’t like it? I’ve heard you lose about 10hp by not having a prop. That’s not necessarily a deal breaker for me as it would only be myself an an 11yr old w minimal gear but would love to hear your views on it.


90 Yammy jet liked to cuisinart grass and spew it up into the water jackets in the head. Overheat. Easy to suck up a rock or shell that jams the impeller. To maintain some performance you need to keep the impeller shimmed just right. Towing another boat is frowned upon as you will be turning big rpm’s. Gas mileage is Shitty. Power loss realistically 35%, At best. Weight sensitive. Don’t back up very well. There are a very few specific instances where you need one


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## Seymour fish (May 13, 2018)

Seymour fish said:


> 90 Yammy jet liked to cuisinart grass and spew it up into the water jackets in the head. Overheat. Easy to suck up a rock or shell that jams the impeller. To maintain some performance you need to keep the impeller shimmed just right. Towing another boat is frowned upon as you will be turning big rpm’s. Gas mileage is Shitty. Power loss realistically 35%, At best. Weight sensitive. Don’t back up very well. There are a very few specific instances where you need one


Oh, and a dog in deep water


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## Hogprint (Feb 23, 2020)

Thanks for the input Seymour fish. It gives me some things to consider. The price seems to be right but the headaches may not be worth it.


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## JC Designs (Apr 5, 2020)

An outboard jet is a “specialty” tool. A must when needed for certain areas, a pita when not! I use them, but again they are for running shallow/rocky areas and this is where they shine.


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## Zika (Aug 6, 2015)

Friend had one on his aluminum boat that he fished in the rocky, shallow areas of Florida's Big Bend. Had so much problems with floating grass and overheating that he pulled it off and now runs a normal lower unit with prop in the same areas.


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## Hogprint (Feb 23, 2020)

Good info Zika. I wonder what the cost of that would be? Yamaha 40 is a good motor from I’ve heard. That may be an option.

edit: just jumped over to eBay/amazon and they had a new SEI lower unit for $1095...


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## Smackdaddy53 (Dec 31, 2012)

I had a 60/45 on my aluminum hull I built just for the jet and it would barely get on plane and when it did I got about 20mph. To get performance up to par with a prop I’d have had to have a 115/80 which was waaay too heavy for a poling skiff. No thanks. I run in 3-4” with my prop setup now and that us skinny enough to get me anywhere I don’t have business being. 
Outboardjets in California is the monopoly company for jet lower units. Everything you need to know can be found through them and talking with them on the phone.


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## JC Designs (Apr 5, 2020)

I can teach ya’ll how to handle floating grass with a jet on a skiff. But, they are slow and real finicky about hull shape, weight, and weight placement. I’ve ran them for many years but am currently on the fence about my next build. Smack’s been using some peer pressure for a tunnel X lol!


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## Smackdaddy53 (Dec 31, 2012)

Remove every other grate on the foot and it will turn it into a salad shooter. I added intake fins to mine to help with rough water crossings but it just wasn’t enough motor.


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## JC Designs (Apr 5, 2020)

Smackdaddy53 said:


> Remove every other grate on the foot and it will turn it into a salad shooter. I added intake fins to mine to help with rough water crossings but it just wasn’t enough motor.
> View attachment 141614
> View attachment 141616
> View attachment 141618


Yeah, that’s a lot of boat for a 60/40.


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## Smackdaddy53 (Dec 31, 2012)

JC Designs said:


> Yeah, that’s a lot of boat for a 60/40.


I got that motor for $700. Sold it for a grand and bought a rebuilt 90 with new prop lower unit. Ran it a couple of years. Ed fished on that fake temperature alarm POS.


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## JC Designs (Apr 5, 2020)

Smackdaddy53 said:


> I got that motor for $700. Sold it for a grand and bought a rebuilt 90 with new prop lower unit. Ran it a couple of years. Ed fished on that fake temperature alarm POS.


Go to bed, it’s 1A:M here!


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## Hogprint (Feb 23, 2020)

Smackdaddy53 said:


> I had a 60/45 on my aluminum hull I built just for the jet and it would barely get on plane and when it did I got about 20mph. To get performance up to par with a prop I’d have had to have a 115/80 which was waaay too heavy for a poling skiff. No thanks. I run in 3-4” with my prop setup now and that us skinny enough to get me anywhere I don’t have business being.
> Outboardjets in California is the monopoly company for jet lower units. Everything you need to know can be found through them and talking with them on the phone.


Good info Smackdaddy. I also found another thread over in the General sect that JC Designs answered w the Outboard jets website. It had a weight to HP chart on it that was pretty informative. I need to to find out what a 16’ Landau weighs now! 
Thanks for all the info. Good stuff.


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## Smackdaddy53 (Dec 31, 2012)

Here’s a little jet jon rigged out by Sonny’s Marine in Port O’ Connor Texas. They are pretty knowledgeable on jets as well.


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