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18-09-2005, 06:26 PM
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#1
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Xr2 Carbs
Does anyone know how much revs or power i might lose by going from .068 main jets to .070 on my xr2?
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18-09-2005, 06:36 PM
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#2
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Registered User
Country: UK
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Re: Xr2 Carbs
Quote:
Originally posted by scottyboy
Does anyone know how much revs or power i might lose by going from .068 main jets to .070 on my xr2?
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i thought XR2's ran .8 sommat for mains but i aint sure
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18-09-2005, 06:47 PM
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#3
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Registered User
Country: UK
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Jay Smith on the subject of correctly jetting a motor
The plugs should be a "paper bag" color to be the ultimate in correct jetting. I don't read plugs as there are too many varibles involved, I have had good luck only reading the piston itself. I make a high speed pass and if the hull will allow it without back washing over the splash well kill it clean. Then I roll # 5 piston ( as generally # 5 is the hot hole on a Mercury and prone to burn if the mixture is too lean ) to bottom dead center and look at the piston crown on the intake side ( that will be the side toward the outside of the block ) with a bend o lite , the intake side of the piston at the intake port should be wet and look moist about the size of a quarter out toward the middle from the port. If the wettness is over across half of the crown your too rich and can lean down a bit. If it is dry and ashy in color your too lean and you need to richen up in a hurry. Maybe other people have different methods but this has always been the ticket for me. Some rely on pyros , I have found that when a motor is too lean a pyro will be too late in its report and the piston is already smoked ( a 2.5 Merc with stock stroke comes to top dead center@ 10,000 rpms at a rate of 120 times a second I'm an old man and I can't react that fast maybe some of the younger ones can but my incounters with a lean motor things just happen too fast ) also on MANY occations I have had customers motors be STUPID rich and the pryos are reading flame not egt and they continue to richen even more chasing thier tails. Also if a pyro is "coked" up" it will also read incorrectly . This is why I haven't alot of faith in the pyro system of jetting. I always tell my customers when I build modified motors to start off very rich and SLOWLY work your way to dialing in your jetting. And by ALL means don't listen to JOE BLOW as to where his motor runs best on jetting as EVERY MOTOR is different and what might run great on one jetting curve might cost you another trip to the machine shop and bank !
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18-09-2005, 06:50 PM
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#4
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hello
Join Date: Mar 2004
Posts: 2,739
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not much, why would you want to though?
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18-09-2005, 06:54 PM
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#5
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Think There supposed to be .068 (Well im assumong there supposed to be .068)but mine have been changed to .070 by little pete coz he wanted to run it slightly rich to reduce the risk of blowing it up! Im gonna put it back to standard and just wondered wot rpm or power i might gain
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18-09-2005, 06:57 PM
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#6
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hello
Join Date: Mar 2004
Posts: 2,739
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A lil bit but not much get a carb plate or stacks and go upto 72's
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18-09-2005, 06:58 PM
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#7
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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carb plate??
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 06:59 PM
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#8
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it says here http://www.mercruiserparts.com/Show_...RETOR+ASSEMBLY
that they are .80's standard. what year is your XR2 dude
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18-09-2005, 07:01 PM
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#9
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Dunno? Think its a 97 But its been rebuilt by ocean racing since then! Think its done about 10hours since then?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 07:01 PM
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#10
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Registered User
Country: UK
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Quote:
Originally posted by scottyboy
carb plate??
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18-09-2005, 07:26 PM
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#11
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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So do ya ditch the air filter? wot sort of rpm do ya gain from fitting these and where ya get em from?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 07:29 PM
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#12
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hello
Join Date: Mar 2004
Posts: 2,739
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I think it depends on what carbs are on the xr2. Duel bowl or single bowl pumper.
Being a newer motor yours would have had the single bowl pumper carbs from the factory but that doesn't mean someone didn't fit the older dual bowl carbs at some point. Some people dont like the pumper carbs as they can make the motor bog down when you stamp on the throttle.
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18-09-2005, 07:51 PM
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#13
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Mine has one acceloration pump per carb but theyve been disconected!
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 08:07 PM
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#14
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Registered User
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Quote:
Originally posted by scottyboy
So do ya ditch the air filter? wot sort of rpm do ya gain from fitting these and where ya get em from?
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i think you gain 2 to 300 rpm. you can make one yourself and its over to JBD to explain how
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18-09-2005, 08:08 PM
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#15
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hello
Join Date: Mar 2004
Posts: 2,739
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Burty's link showing 80's is on the older 150 XR2 motor with dual bowl carbs so dont worry about it.
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18-09-2005, 08:20 PM
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#16
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Come on then JBD how'd ya make em or where ya buy the proper ones?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 08:31 PM
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#17
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Registered User
Country: UK
Location: Weston Super Mare
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Quote:
Originally posted by scottyboy
Come on then JBD how'd ya make em or where ya buy the proper ones?
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check this thread out, what you are looking for is on page 2. and yes you did start the thread
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18-09-2005, 08:37 PM
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#18
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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No thread rob?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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18-09-2005, 08:42 PM
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#19
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Registered User
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Quote:
Originally posted by scottyboy
No thread rob?
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O Bollox i forgot to put it in
i'll try again
http://www.boatmadforum.co.uk/showth...b&pagenumber=2
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18-09-2005, 08:47 PM
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#20
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hello
Join Date: Mar 2004
Posts: 2,739
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I think that 13443 on the plate in the photo is the merc part no.
Or you could cut an airbox up or buy some velocity stacks from anyone who does race motor bits.
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