Scavenger Tube Needed?

[roadnsky]

I was aware that there are 2 versions in terms of screws. The only gasket i had was a 5 screw. I figured it would work. Are you saying the 4 screws always or tend to leak?
?

"...All Zenith carburetors produced since the mid 1980's have a fifth retaining bolt in the front of the upper and lower housings. Prior to this generation of carburetors, there were only four bolts holding the two housings together, and all four bolts were located around the float chamber. This configuration left no fastener to pull the front of the housings together. How this fifth bolt (or the lack of it) relates to a rich running condition can best be understood by a quick review of how the internal pressure within the carburetor is regulated to maintain inlet pressure instead of ambient atmospheric pressure..."

To read more...

http://www.moyermarine.com/pressure_regulation.htm

[roadnsky]

I think I'm gonna report that post as obscene.

Ok, one more.
This one's RATED "R" Neil so look away quick...


You can see in this one how the scavenge tube would collect any fuel pooling in the carb throat.

[Rbyham]

Jerry... it looks like there are two somethings connecting to the top flange in your R rated picture. I see the rear one is the scavenge tube. What is on the front? Is it possibly the pcv connection? If not let me ask this. Can I connect the scavenge tube and my pcv valve together into front and rear of the carb flange? Thanks.

[roadnsky]

Oh Boy...

Jerry... it looks like there are two somethings connecting to the top flange in your R rated picture. I see the rear one is the scavenge tube. What is on the front? Is it possibly the pcv connection? If not let me ask this. Can I connect the scavenge tube and my pcv valve together into front and rear of the carb flange? Thanks.

It is indeed the PCV outlet. And YES that's where you should attach it.
This pic shows it a little better.
(Man, Neil is never gonna speak to me again )

In my defense, I should point out that this is a very old picture...

[sastanley]

Yes..the right hand connection goes to Jerry's PCV valve coming out of the valve cover.

edit - shoulda refreshed

Jerry - the paint is even mis-matched!

[roadnsky]

Jerry - the paint is even mis-matched!

Well, if I posted a current pic we're gonna really get into off topic territory!

[ndutton]

Yes I do have indigo Pcv upgrade.

Toe-may-toe, toe-mah-toe
Upgrade, band-aid

(couldn't resist, I confess I had a ghost writer on that one)

[Rbyham]

Jerry.. The pics are very helpful. But I note the nut on your flange bolt appears crooked to me. Could not be cross-threaded? Probably not but it looks off...

[roadnsky]

Jerry.. The pics are very helpful. But I note the nut on your flange bolt appears crooked to me. Could not be cross-threaded? Probably not but it looks off...

Nope. All good there, but thanks for asking...

[Rbyham]

Hey folks. I just got rebuilt carb all buttoned down and ready for test start. Awaiting new fuel tank I had it running direct from portable can to fuel pump. Upon priming with fuel pump handle i smelled gas. Checking I found about 5 drips per minute coming out of scavenge hole in air throat. I obviously will not try start up. But is this at all normal? I have scavenge pipe on the way from MMI but still this feels like too big a leak. Could I have messed up on carb rebuild?

[Rbyham]

Could I have over pressurized the system with fuel pump primer? I took fuel line out of tank to break syphon but still dripping.

[Rbyham]

False alarm. I depeessurized system. Opened boat up for an hour. Ran all blowers and went for startup. She fired and ran perfect. Purrs at about 700 rpm after final idle adjustment. No runs drips or errors. As soon as scavenge tube arrives will install. Cmon Ken! :-)

[edwardc]

The drip is probably indicative of fuel getting past the float valve. Things that can cause this are:

• Dirt/crud on the needle valve seat
• Worn/damaged needle valve tip
• Too much fuel pressure
• Bent/misadjusted float
• partially flooded float body

[Dave Neptune]

Check

Should be no leak! The needle seat probably has some KRAP in it. Or something is amiss with the "float assembly", make sure that you shake the float and listen for some liquid sloshing~if the float sinks the needles open but this would be a lot of fuel. Your drip sounds like a dirty seat.

The scavange tube is there incase there is a leak like you have.

Good call on no start!

Dave Neptune