F90 G3 jet drive setup inf.

[Majesticman]

I have a G3 18 foot Tunnel with a F90 21 inch shaft prop and factory jack plate. Motor already sets 7 inches or so high.

I want to exchange my prop for a jet until KY lake rises.

Will the 6 or 7 inch tunnel cause problems?

Do I need to also buy a cable for reverse and forward?

Where can I get my deal on the unit. I went to the California's Mfg site and they don't show any dealers in my area. (That needs to be fixed)

I can use any inf. you can give because I am lost.

Thanks guys.

 

[rodbolt]

Re: F90 G3 jet drive setup inf.

outboard jets simply dont like tunels, they like flat bottoms or bottoms with less than 5* of rise.
second jets like to have the intake at or slightly above the hull bottom so they can suck an air free stream of water while keeping the jet intake as close to the surface as possible to cut down on drag.
will your tunnel hull accept a jet? yes. will turning and acceleration suffer? yes.
with a jack you already have several inchs of setback,means the motor has to be mounted even higher.
what you need to do is send your hull information and engine model number to the jet manufacturer and follow there reccomendations.
trust me they will work with you and give good advice and they also like pictures of the rig.
I understand low water and shallow water operation.
in my area we have a terrible amount of water just a lot of it is very thin.
with a jet drive shallow water operation is possible just always remember if there is less than about 2ft between the bottom and the jet intake NO idleing or low speed ops are reccomended.
they turn into giant hoovers and suck debris,sand and mud from the bottom that tends to clog impeelers and engine water passages.

 

[Lone Duck]

Re: F90 G3 jet drive setup inf.

I have a G3 18 foot Tunnel with a F90 21 inch shaft prop and factory jack plate. Motor already sets 7 inches or so high.

I want to exchange my prop for a jet until KY lake rises.

Will the 6 or 7 inch tunnel cause problems?

Do I need to also buy a cable for reverse and forward?

Where can I get my deal on the unit. I went to the California's Mfg site and they don't show any dealers in my area. (That needs to be fixed)

I can use any inf. you can give because I am lost.

Thanks guys.

google enhancing outboard jet by Cris Gorsuch Or snyder boats . They have very good information and diagrams.

 

[rodbolt]

Re: F90 G3 jet drive setup inf.

dont google jack.
simply contact the jet unit manufacturer and get it from the horses mouth.
kinda like how I got in trouble here in the shop a while back.
customer had an insufficient capacity and flow rated filter.
I tried explaining to the jackleg why it would not work.
said jack leg told me so n so at NAPA told him it would and sold it to him.
I told said jackleg to take it to napa and they would fix it and walked away.
I did have to apologize to the marina owner but I refuse to apologize to said jackleg.

 

[Lone Duck]

Re: F90 G3 jet drive setup inf.

dont google jack.
simply contact the jet unit manufacturer and get it from the horses mouth.
kinda like how I got in trouble here in the shop a while back.
customer had an insufficient capacity and flow rated filter.
I tried explaining to the jackleg why it would not work.
said jack leg told me so n so at NAPA told him it would and sold it to him.
I told said jackleg to take it to napa and they would fix it and walked away.
I did have to apologize to the marina owner but I refuse to apologize to said jackleg.

Bad experience for you. But I stand by my 1st post.

 

[Majesticman]

Re: F90 G3 jet drive setup inf.

Thanks for the inf. guys. I am only using the unit for 1 or 2 months until KY Lake rises thanks to a committee (of two, one a car dealer) that got us ripped off ($28K) on a dredging job at Pirates Cove. Sorry about getting off subject.


I am not worried about performance since I will be going straight out and I am in my spot. I just don't want to waste money or hurt the motor. We have a mud bottom and I am just considering giving it hell in the two feet of water in the marina (it does that) and cruising over the 8 inch 100 foot hump that was left. The boat is made for skinny water. I was really concerned if the tunnel would feed me water or cause cavitation.

I will use all the inf. both of you guys gave me.

Thanks you!