44mm carb set up i'm lost.

[the WaTeRhAwK]

xKawi550x - which color sbn carb did you buy?, was it new, or what's the history on it that you know of?

 

[the WaTeRhAwK]

just for the record , matt.... that's the first time I ever seen anyone over here, let alone a moderator, refer someone to pwctoday for answers regarding tech issues.

 

[tightithrash]

just admit it..... You really love matt.

 

[the WaTeRhAwK]

just admit it..... You really love matt.

he's an awesome cat, ....lol, a genius, and I don't mean that sarcastically , either. don't know what we'd do without him.

 

[Maxumflux]

xKawi550x - which color sbn carb did you buy?, was it new, or what's the history on it that you know of?

i couldn't tell you what the old jetting is. I bought a west coast pipe and a ride plate and it came with it. i'm gonna go with free style. is there any way to determine the jet i have in it?

The carb is black..
This thread is getting pretty funny :Banane13::biggrin:

 

[Maxumflux]

there is no cylinder work done. just a milled head.

 

[Matt_E]

You will need to remove the diaphragm cover, diaphragm, jet cover block, and then both jets.
The bigger main jet will have a number written on the side.
The pilot jet will have a number written on the bottom face.
Those are your jet sizes.

You should also remove the popoff arm & spring and the needle valve to determine what size it is (written on the face of the valve seat).
I'd advise you to read the manual I linked to.
It should answer most of your questions about these carbs.

 

[Maxumflux]

You will need to remove the diaphragm cover, diaphragm, jet cover block, and then both jets.
The bigger main jet will have a number written on the side.
The pilot jet will have a number written on the bottom face.
Those are your jet sizes.

You should also remove the popoff arm & spring and the needle valve to determine what size it is (written on the face of the valve seat).
I'd advise you to read the manual I linked to.
It should answer most of your questions about these carbs.

thanks:Banane09:

 

[Maxumflux]

are the color of the jets relevent? am i gonna need a carb rebuild kit if i change jets?

 

[WFO Speedracer]

The jets are brass colored since they are made of brass,some may be shiny and others not due to corrosion but no the color does not matter,the number on the jet does matter,you will probably need a good light and a magnifying glass to read them .

 

[Maxumflux]

do i need to take the carb off to get to the jets?

 

[Matt_E]

Considering how easy it is to take off the carb, and considering how much of a pain in the ass it would be to remove the jets with engine & carb inside a hull, YES.

 

[Super Dee]

I had a 1986 550 with the piston port engine and it was set up as follows (for a few hundred feet above sea level):

Coffman's half-pipe, Tau Ceti flame arrestor, stock porting, stock compression. Once I had my SBN44 tuned perfectly, I had this jetting:

Pilot: 100
High: 120
Pop-Off Pressure: 15psi.

That should get you pretty close to the right set up.

I read somewhere a while back that the total jetting (adding the high speed and pilot jet numbers together) on a piped 550 is usually between 220 and 225. In my case it's 220 (100 + 120). On a stock ported piston port motor with an aftermarket flame arrestor you'll want the pop-off pressure at 15 to 16 psi.

I don't know what, if any, the difference in jetting requirements are for the later reed engines. Reed engines were put in the 550s starting late 1991 and were gray in colour. All stock painted piston port engines are black.

 

[the WaTeRhAwK]

I just pulled the carb and looked at the jets, the high speed is set at 135, low is 100. when you're running extra high rpms you need the extra fuel going in at the top or you will run it too lean and burn it. if you're going with the 13 degree prop and short stainless chamber, those settings are going to get you closer to where you need to be. this setup is a stock bore mildly ported just to avoid carbon buildup, so no port timing has been changed, etc..

the small chamber will dramatically raise your top rpms, as well as the low pitched prop. if you run a 120 high jet, you'll burn the top end out of it. it seems like that was the reason for one of my top end rebuilds that season.

I also run 17 popoff pressure. it's the silver spring, and I had to cut two coils off of it to get it to the right setting.

 

[Matt_E]

it's the silver spring, and I had to cut two coils off of it to get it to the right setting.

xKawi550x - you definitively want to measure popoff pressure with a gauge if at all possible. Just going by chart in the manual can be inaccurate, as Waterhawk's example illustrates.

 

[the WaTeRhAwK]

xKawi550x - you definitively want to measure popoff pressure with a gauge if at all possible. Just going by chart in the manual can be inaccurate, as Waterhawk's example illustrates.

here's another thing, most of the "experts" will tell you that you're not supposed to cut a spring, bend or stretch one. the bending and stretching being the most detrimental , as opposed to cutting the spring. and once you get the spring that gets you "close" to the needed pressure, you are to slightly bend the needle arm up or down to compensate. well, that didn't work, and I had to cut the spring to avoid bending the arm too far. this carb was a PITA to setup. I had an assortment of springs and the cut silver was the only one I could use for my setup.

 

[Matt_E]

I have found springs of one color to vary wildly.

 

[Maxumflux]

well it looks like the carb is coming off tonight then. i'll post the numbers on here asap...