20/30 Johnson Jet leg.

Post Reply
User avatar
shuether
Posts: 4
Joined: 10 Oct 2018, 09:55
Location: Alberta, Canada

20/30 Johnson Jet leg.

Post by shuether » 23 Oct 2018, 14:06

So I've got a 1993 20hp Johnson and I've come across a jet leg I should be able to pickup for under $500CAD, depending on condition. My current boat is a 14' Mirrocraft that does excellent with the 20hp prop, handles 2-4 people with only 4kmh diff in top speed. This boat also did really well with a 70's Chrysler 15hp(~10hp when compared to the Johnson) with two people and gear. I've been wanting to get an outboard jet for a while to make it easier to explore some of the rivers near a friends place in BC that I visit every summer. I know the smaller jets are often frowned upon because of the 30% performance tax doesn't leave much power at the jet.

My question being this: is it worth messing with this jet leg? Or would I be better off to look at a 30+ jet down the road? Best I've seen is $3000-4000 for anything decent in my area. Also anything to watchout for when I go look at the jet leg?

At this point I'm thinking its worth a try. If it feels under powered on the 20, I can do the carb/intake off a 30 and get a little more out of it.
Current rig:
1978 Mirrocraft 14' Resort Model F-4604
1993 Johnson 20
1975 Chrysler 15 for sale

Projects:
1976 Chrysler 10 need flywheel, for sale soon

See my IG for more pics: @SHuether

Xtremeboats
User avatar
handyandy
Posts: 544
Joined: 02 Jun 2015, 09:56
Location: Bedford Indiana

20/30 Johnson Jet leg.

Post by handyandy » 02 Nov 2018, 09:18

that small of a jet motor is only good for 2 guys and light load if it's on a light boat which it sounds like your boat is light. If it's a v bottom boat forget it. You absolutely will want to get the 30-35hp carb and intake to up the performance of that engine, it still won't be fast though but should have enough to get on plane with two guys in a light flat bottom. What size is your boat 14' long how wide? flat bottom or semi v?

There are other things you can do with those little 2 cyl omc engines you can get them to scream pretty good considering how small they are. Guys race them on little hydros and v bottom boats with props and get really impressive speed. But prop is way different than jet. With that said you can shave the head a little, go to the bigger carb, better reeds, and shorten the exhaust tuner some, jet the carb accordingly for more performance, but for most that is beyond what they want to do. It would help that motor with a jet, but at the end of the day your still limited as to how much water that little jet pump can move.

User avatar
shuether
Posts: 4
Joined: 10 Oct 2018, 09:55
Location: Alberta, Canada

20/30 Johnson Jet leg.

Post by shuether » 05 Nov 2018, 17:08

Yea my boat is pretty light, about 180lbs empty. Its a 1978 Mirrocraft Resort F4604 14' x 57". The back end is pretty much flat but the front has a pretty good v so it handles lake chop very well. I'm thinking I might be a better off to try to find a 30-40 hp jet and just have two motors. There is definitely situations where either had its advantages. Or maybe I should just go the route of building a mini jet boat and keep that for the river exploration... so many options!
Current rig:
1978 Mirrocraft 14' Resort Model F-4604
1993 Johnson 20
1975 Chrysler 15 for sale

Projects:
1976 Chrysler 10 need flywheel, for sale soon

See my IG for more pics: @SHuether

JoshKeller
Posts: 447
Joined: 20 Aug 2012, 22:01
Location: martinsburg, wv

20/30 Johnson Jet leg.

Post by JoshKeller » 26 Nov 2018, 17:12

with a 180 lb boat, it should do just fine. the general suggestion is 25lbs per powerhead (not jet) horsepower

Post Reply