Jet Drive outboard motor:

[REW]

Bfish,
My brother tells me that it is a 2012 or a 2013 motor.

But, due to not working well for the crew, it has received virtually no use.

Be safe

[grizzley]

REW:
I think all the outboard jet drives, for all the manufacturers, are made by one company: "outboard jets" in CA. It may be of some benefit to call them and see if they can provide some helpful info.

[REW]

The information about the 60hp power head on the 40hp marked jet drive certainly seems correct:

https://www.mercurymarine.com/en/us/...specifications

The 40hp prop drive is a 45.6 cubic inch power head.

The 60hp prop drive is a 60.8 cubic inch power head.


https://www.mercurymarine.com/en/us/...ards-25-80-hp/

The 40hp jet drive is a 60.8 cubic inch power head.

Thanks for the update.

[Huntindave]

Originally Posted by REW

The information about the 60hp power head on the 40hp marked jet drive certainly seems correct:

https://www.mercurymarine.com/en/us/...specifications

The 40hp prop drive is a 45.6 cubic inch power head.

The 60hp prop drive is a 60.8 cubic inch power head.


https://www.mercurymarine.com/en/us/...ards-25-80-hp/

The 40hp jet drive is a 60.8 cubic inch power head.

Thanks for the update.

Yep, Thats what I found when I replied earlier in your thread. As to swapping out the jet pump impellers; I'd suggest (just as you would when selecting a prop) that you ask him what RPMs they are getting presently.

I'm not sure swapping impellers is an option but it may be. I believe the 6 5/8 and 6 7/8 refers to the diameter rather than the pitch. If you are able to change to the other impeller, they will also have to replace the inner liner to match the impeller diameter.

IMHO; Given that you indeed have a 60hp powerhed, The engine weight or transom setup, may be contributing more to the performance issue, rather than lack of power. Tweaking and tuning the engine for altitude certainly won't hurt.

[CKM]

Originally Posted by Huntindave

Yep, Thats what I found when I replied earlier in your thread. As to swapping out the jet pump impellers; I'd suggest (just as you would when selecting a prop) that you ask him what RPMs they are getting presently.

I'm not sure swapping impellers is an option but it may be. I believe the 6 5/8 and 6 7/8 refers to the diameter rather than the pitch. If you are able to change to the other impeller, they will also have to replace the inner liner to match the impeller diameter.

IMHO; Given that you indeed have a 60hp powerhed, The engine weight or transom setup, may be contributing more to the performance issue, rather than lack of power. Tweaking and tuning the engine for altitude certainly won't hurt.

should be able to turn it to a 60hp with a dealer computer. for a cost of course. you must be able to change the impeller. no way they would run the same impeller on a 40 as they do a 60. I'd bet the same jet drive is used on both. physically there is probably no physical size/weight difference between the 40/60.

[Huntindave]

CKM,

How are you going to account for the huge difference is the physical size of displacement? These motors are not just different in how they are tuned.

The difference in cubic inch displacement is huge. The 40hp power head 45.6 cubic inch and the 60hp power head is a 60.8 cubic inch .

This is all a mute point anyhow as REW has listed the model number and it is a 60hp power head.

[jet man]

I have built jet style jon boats for use on the river.
To max performance it really takes a tunnel designed specifically for jets which in the in the boat style you are referring to would be not likely.
At a minimum it takes a jack plate so you can fine tune the intake point. With the boat you are referencing you are likely plowing water with the intake which will greatly affect performance. Tough application in my opinion.

[jet man]

Call Kevin Turner at:
http://www.riverpro-boats.com/
before I would invest 20K in an inflatable I would see what he could build for you. They are working on an outboard jetboat and I guarantee it will be built to take a beating.
I run one of their inboard jet boats and they build a tough product and can do custom work.
You have nothing to lose by having them call him.

[grizzley]

REW: You stated that the other Zodiac works just fine with the Yamaha Jet. I doubt if it is the motor itself, unless it is related to the additional weight of the motor. Lots of guys run 60/40 Merc. jets on Jon boats in our area.
It was mentioned about how far the foot should be below the hull; too low and the jet housing will cause a lot of drag. Another thing they don't like is air bubbles. If the reverse gate is partially engaged it will lose a lot of power.
A pic. of the setup, with the motor trimmed down, may give someone an idea as to what may be causing the problem.

Get them to contact the jet mfg.: they build them, they should know!

[REW]

Thanks for everyone's thoughts.
I have forwarded these ideas to the search team. It is up to act on any of them.

Thanks again.