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  #11   Report Post  
us104
 
Posts: n/a
Default 20 to 30hp Johnson

Thanx for help!
The engineblock and cc is the same so it must be as you say.
Do you if it is possible to work with the carb or if its easier to get hold
of a 30hp carb?
matts


"Tony Thomas" wrote in message
news:0QH9b.475528$Ho3.80058@sccrnsc03...
Not sure on that year. I know the carbs are different. The exhaust tuner
may be different along w/ the ports.
Start w/ the carb and go from there. Should get you some power anyway.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"swedishconnection" wrote in message
...
Anyone knows anything about tuning a Johnson 20hp,1990,Two-stroke to

30hp??
I do gladly accept any advice on that!
matts


"swedishconnection" wrote in message
...
I have a Johnson 20hp,1990,Two-stroke.Just run 60 hours.
To pull waterskies with my Zodiac I need 10 more hp.
Does anyone know how complicated it is to "scare" the motor to 30 hp?
How is it done?
Grateful for any tip!
matts








  #12   Report Post  
Trainfan1
 
Posts: n/a
Default 20 to 30hp Johnson

There is no "work" to be done on the carb. The 30 carb has a larger bore.

Rob
*
*
*

"us104" wrote in message
...
Thanx for help!
The engineblock and cc is the same so it must be as you say.
Do you if it is possible to work with the carb or if its easier to get

hold
of a 30hp carb?
matts


"Tony Thomas" wrote in message
news:0QH9b.475528$Ho3.80058@sccrnsc03...
Not sure on that year. I know the carbs are different. The exhaust

tuner
may be different along w/ the ports.
Start w/ the carb and go from there. Should get you some power anyway.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"swedishconnection" wrote in message
...
Anyone knows anything about tuning a Johnson 20hp,1990,Two-stroke to

30hp??
I do gladly accept any advice on that!
matts


"swedishconnection" wrote in message
...
I have a Johnson 20hp,1990,Two-stroke.Just run 60 hours.
To pull waterskies with my Zodiac I need 10 more hp.
Does anyone know how complicated it is to "scare" the motor to 30

hp?
How is it done?
Grateful for any tip!
matts










  #13   Report Post  
Trond Solem
 
Posts: n/a
Default 20 to 30hp Johnson

Check if the hole in the intake manifold is smaller than the carb. Some of
these motors have 30hp carbs, but the hole in the manifold behind the carb
is much smaller than the hole in the carb. I suppose you know what to do
about it...


"Trainfan1" wrote in message
...
There is no "work" to be done on the carb. The 30 carb has a larger bore.

Rob
*
*
*

"us104" wrote in message
...
Thanx for help!
The engineblock and cc is the same so it must be as you say.
Do you if it is possible to work with the carb or if its easier to get

hold
of a 30hp carb?
matts


"Tony Thomas" wrote in message
news:0QH9b.475528$Ho3.80058@sccrnsc03...
Not sure on that year. I know the carbs are different. The exhaust

tuner
may be different along w/ the ports.
Start w/ the carb and go from there. Should get you some power

anyway.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"swedishconnection" wrote in message
...
Anyone knows anything about tuning a Johnson 20hp,1990,Two-stroke to
30hp??
I do gladly accept any advice on that!
matts


"swedishconnection" wrote in message
...
I have a Johnson 20hp,1990,Two-stroke.Just run 60 hours.
To pull waterskies with my Zodiac I need 10 more hp.
Does anyone know how complicated it is to "scare" the motor to 30

hp?
How is it done?
Grateful for any tip!
matts












  #14   Report Post  
Tony Thomas
 
Posts: n/a
Default 20 to 30hp Johnson

Different carb. By the way, what is your compression. While going to a
larger carb and rejetting, you might want to consider upping the compression
to say 140 psi by having the head shaved. This will really make a
difference on acceleration and you can advance the timing since you will be
running 93 octane fuel. Just make sure you get a tach of some kind to hook
up so you don't overrev the engine or you know what prop to change to.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"us104" wrote in message
...
Thanx for help!
The engineblock and cc is the same so it must be as you say.
Do you if it is possible to work with the carb or if its easier to get

hold
of a 30hp carb?
matts


"Tony Thomas" wrote in message
news:0QH9b.475528$Ho3.80058@sccrnsc03...
Not sure on that year. I know the carbs are different. The exhaust

tuner
may be different along w/ the ports.
Start w/ the carb and go from there. Should get you some power anyway.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"swedishconnection" wrote in message
...
Anyone knows anything about tuning a Johnson 20hp,1990,Two-stroke to

30hp??
I do gladly accept any advice on that!
matts


"swedishconnection" wrote in message
...
I have a Johnson 20hp,1990,Two-stroke.Just run 60 hours.
To pull waterskies with my Zodiac I need 10 more hp.
Does anyone know how complicated it is to "scare" the motor to 30

hp?
How is it done?
Grateful for any tip!
matts










  #15   Report Post  
us104
 
Posts: n/a
Default 20 to 30hp Johnson

Thanx for all advice - it is like I thought - but good to have some advice.
By the way - I use a ProPulse - adjustable propeller.Tried it for the first
time this summer.
Very good prop specially in the circumstances I use my boat!
http://www.propulse.se/english/index.html
Thanks again!
matts

"Tony Thomas" wrote in message
news:0QH9b.475528$Ho3.80058@sccrnsc03...
Not sure on that year. I know the carbs are different. The exhaust tuner
may be different along w/ the ports.
Start w/ the carb and go from there. Should get you some power anyway.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"swedishconnection" wrote in message
...
Anyone knows anything about tuning a Johnson 20hp,1990,Two-stroke to

30hp??
I do gladly accept any advice on that!
matts


"swedishconnection" wrote in message
...
I have a Johnson 20hp,1990,Two-stroke.Just run 60 hours.
To pull waterskies with my Zodiac I need 10 more hp.
Does anyone know how complicated it is to "scare" the motor to 30 hp?
How is it done?
Grateful for any tip!
matts










  #16   Report Post  
noah
 
Posts: n/a
Default 20 to 30hp Johnson

On Tue, 16 Sep 2003 08:55:24 GMT, "swedishconnection"
wrote:

Have a look at Zodiacs homepage - and good luck tubing!
http://www.zodiacmarine.com/img/prod/gz7a.jpg
matts


No offense intended, matts.
I just don't see it as a skiing package.
....then again, when I was younger, I did a few things that weren't
*in the book*.
Good luck with it, and good skiing.
noah
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