Changing Props To Jet--any Remarks?

signum · 07 February 2006, 22:01

For some time now i'm thinking if i could find the way to change the propellers system to a jet system on my outboard motors....(2x225HP)
I would like to hear your remarks on that subject...is it worthy?

CJL · 07 February 2006, 22:38

Its a no go I think.

Mercury did a 60hp jet outboard but its was different from the 60hp prop version in a number of ways. It certainly wasn't like you could just change the gearboxes.

Chris

Hightower · 07 February 2006, 23:01

I saw a Mariner at Fairweather once, that was a 60 I think. They had dropped off the Gearbox and replaced it with a Jet unit. I don't ever remember Lee being that fond of it though. A failed experiment one thinks. I was up for sale about a year ago.

Nasher · 07 February 2006, 23:41

Johnson/Evinrude did a jet drive unit that bolted on in place of the bottom gearbox assembly.

The OMC workshop manual I have kicking around for 150 and 175HP 60deg loop V engines shows it in detail and has a full strip down etc.

The manual dates from the late 80's or early 90's, I presume they must still be out there somewhere secondhand or old stock, but might take some finding.

Be interested to know some more just out of curiosity.

Nasher.

codprawn · 07 February 2006, 23:45

http://www.outboardjets.com/

This company offer jet units for most outboards.

Unless you have a desperate need to operate in amongst swimmers don't bother - outboards are high revving which will cause probs - if you really want jets get a boat with a diesel inboard engine and a proper jet drive.

Cookee · 08 February 2006, 09:05

Yamaha also made / make one - retro fitting a one off gearbox / drive system to an existing outboard would be an enormous job, so unless the link above offers you a bolt on part I wouldn't even think about it - if they were a good solution then they would be more common! Better off converting to an inboard as already suggested - nothing better than a supercharged V8 with dry exhausts and a Berkely jet!

signum · 08 February 2006, 11:42

thank you all for your replies.....i'm sure now that it doesn't waorth the trouble....
anyways anything you need about Greece etc i'm at your disposal......

Matt · 08 February 2006, 12:17

Yes, I have a small job for you. Would you mind taking a trip to Santorini and "roughing up" a certain Manos Catspiss? Payment can be made on flexible terms.

signum · 08 February 2006, 12:20

why? you have a problem with manos?????? i beleive that you mean manos witht the famous marco!!!!!!

Simon B · 08 February 2006, 15:46

Your horsepower will take a nose dive and fuel consumption will go up with an OB jet. I believe this is a similar when an inboard diesel is coupled to an outdrive leg type thingy or a jet unit.

The Garfish · 08 February 2006, 17:42

Quote:

Originally Posted by signum

you mean manos witht the famous marco!!!!!!

noe yew nobbend. wee meen manoos wiv de famus bajja

gArf

signum · 08 February 2006, 22:31

thank you also simon b for yr reply.... anyways asking also here the johnson and some friends mechanics i finally dropped the idea......

Andy Gee · 09 February 2006, 14:21

Heading through to Edinburgh this morning I passed a RN Bomb Disposal Delta of around 7m fitted with twin Mariner 90 jet drives. Couldn't get a picture as on the phone at the time!!

Andy

signum · 09 February 2006, 14:55

thanks andy...that y remembered it counts!

Turbodiesel · 10 February 2006, 22:45

Ive just taken those two jets off the bomb disposal boat. They dont like them. Ive done loads and loads of jet trials for the MoD on all sorts of boats and engines. Most people dont like them. The boat really really needs to be designed to have jets, the engines need to be lifted up by a few inches, so the intake is just in the water. You loose a massive amount of power (about a quater to a third of your power). They are also alot different to control. Like a jet ski you have to have some power on to control a turn. I think the only reason for having a jet is if your operating in very shallow water 90% of the time. That bomb disposal boat will do 26-27knts with the jets and with gearboxes (props i mean) its doing 36-37knts. Thats alot of difference. Also the impellers need quite alot of maintanance if they are worn of get some crap caught in them they loose even more power as the jet will not work efficiently. Also if your operating in shallow water the intakes do get bloked up with seaweed etc and some times need unbloking.
However they are a very good safety feature, especially for the diving teams, as they have people in the water all the time and very good for safety boat work. No one likes to have a prop spinning near them do they.
Or like i think if you have people near your engines in the water really why not just switch the engines off!!!

signum · 10 February 2006, 23:07

thank y turbodiesel for yr reply.
i didn't beleive that the differnce in knts would be that much!
the only reason why i made this thread in the beggining was because i was seeing the jet skiis day by day to increase here and i though...why not and in outboards?