Carb secondary slow cut valve (1 Viewer)

[Rustic76]

I just rebuilt my stock Carb this weekend and there is one spot I can’t find an answer to.....

I need to figure out the clearance between the little lever on the slow cut valve and the linkage arm that pushes down on it. Mine doesn't look like it’s making contact even at WOT. In the pic above, the red arrow is pointing to the slow cut valve.

Overall, my carb rebuild was a success, except for a weird flat spot in acceleration at full throttle. If I slightly back off the gas pedal, the secondary kicks in. Wasn’t sure if this issue correlated with the slow cut valve not being actuated?? It is also a little herky-jerky when the secondary initially opens.

Here are some photos of the freshly rebuilt carb. I was a little intimidated at first by tackling the rebuild, but it was way more simple than expected.

 

[NeverGiveUpYota]

It’s a matter of futzing w/ it. I ‘think’ it needs to be fairly horizontal but I do know some folks tweak theirs a little up or down. As I recall from talking to @mwebfj60 about it after I’d done mine. Drive it and see how it reacts.

 

[NeverGiveUpYota]

Apologies. If it’s not making contact then bend the lever up some. Check it by forcing it to move and watch the other area that affects it. Sometimes things get bent (like I’m telling you to do too) by POs...

 

[Rustic76]

It’s a matter of futzing w/ it. I ‘think’ it needs to be fairly horizontal but I do know some folks tweak theirs a little up or down. As I recall from talking to @mwebfj60 about it after I’d done mine. Drive it and see how it reacts.

I’ll give that a shot. I bent the arm up slightly until the slow cut valve was fully pushed at full throttle. We will see how that goes on my trip into work this afternoon.

I also just noticed a small wet spot from fuel at the carb base/manifold. I used the gaskets supplied in the kit for both sides of the carb spacer....wonder if I should have left those both out?

 

[NeverGiveUpYota]

Not unless your carb spacer was pristine. How was the bottom surface of the carb? Any minute scratches could allow fuel to seep thru. How’s the throttle bushing feel? Can you wiggle the fan side end up and down? If the bushing is bad and most are at this point, it can leak there too. Check your 4 nuts too and be sure they’re snug. Did you cut a 12mm closed end wrench to help you get a better grab?

 

[Rustic76]

The 4 nuts are nice and snug. I was able to get a small 12mm in there. I’ll check the gasket and look for nicks in the spacer. There looked to be be a bit of FIPG on the manifold side when I initially pulled the carb.

Well bending the arm on the slow cut valve did the trick. Vast improvement in overall acceleration and no more spudder at WOT. Having a functioning secondary is a game changer!

 

[NeverGiveUpYota]

The 4 nuts are nice and snug. I was able to get a small 12mm in there. I’ll check the gasket and look for nicks in the spacer. There looked to be be a bit of FIPG on the manifold side when I initially pulled the carb.

Well bending the arm on the slow cut valve did the trick. Vast improvement in overall acceleration and no more spudder at WOT. Having a functioning secondary is a game changer!

How much of a bend did you need to give it compared to when it wasn’t being actuated?

 

[NeverGiveUpYota]

Mine was literally loaded w/ red and blue rtv pretty much everywhere. It was amazing.

 

[Rustic76]

How much of a bend did you need to give it compared to when it wasn’t being actuated?

When I started, the linkage arm wasn’t even making contact. It prob took 1/4 or more of bending upward to get it working.

 

[FJ40Jim]

To adjust SSCV:
Manually push down on the lever of the SSCV, note the max stroke travel of the plunger.
Operate the throttle, observing the SSCV plunger movement. It should lift the plunger to about 75% of max travel.
Make sure it is not overstroked as it will bind the carb at WOT and damage the valve.
Bend the lever arm as necessary to achieve correct travel.

 

[Rustic76]

Thanks @FJ40Jim

Jim, what is your opinion on using the supplied gaskets for the carb spacer?

 

[FJ40Jim]

I don't have an opinion.
The insulator has gasket permanently bonded to both faces. It is supposed to be reusable. If the gasket material is badly damaged, then the insulator should be replaced or the gasket material should be removed & replaced by bonding new gaskets to the insulator.

 

[FJ40Jim]

Just looked at the pic in post #1. The linkage is assembled wrong, which explains why the SSCV adjustment is wacked.

Here's a couple pics that might clarify what it should look like:

 

[Rustic76]

Thanks Jim. I fixed the linkage and got the SSCV where it needs to be. Those pics were a big help.

The test drive into work was great! My 2F feels like a fire breathing dragon compared to before the carb rebuild.