Duel fuel pumps

[preith]

Excellent info guys. Thanks.

It sounds like I have to vent the bowls.

Not to beat a dead horse here, but as far as I know, you have to do more than just vent the bowl. If you end up venting the bowl on the large cover, you can then epoxy the holes in the jet chamber area shut (the ones which allow the fuel to flow in from the bowl). Keep the end open then to vent the jets.

Phil

[Ron Carter]

I agree that this is a carb problem and not a fuel flow problem brought on by low pressure. Good luck and let us know what you find / what works.

BTW, I have 2 Carter pumps on a single pickup. I am running an ATL fuel cell with a surge tank. My pumps are configured as an either / or situation. So If one pump were to fail I can manually switch over to the second pump with a flip of a switch.

[tholt29]

Here are a couple of pictures of my carb vents... It's the little black L tube to the right of the jet cover. I also included an internal shotvso you can see the baffle. This was all done by Rebello and I can't fully explain how it improves things, but it does seem to work! (as is evident by the blue tint of the race gas on the carbs)

Tom

[ctomkins]

Great photos Tom. :classic:

Much appreciated.

Thanks.

[panchovisa]

Tom, thanks for the photos. I will be getting my tripple Mikuni set up ready soon and will make the mods before installing.

I really like your strut brace, where did you get it?

[tholt29]

Panchovisa said:

>I really like your strut brace, where did you get it?

>__________________

>If you want it done right then do it yourself.

You answered the question for me! I made it out of .062 mild steel tubing and some 1/8" plate. Cheap and effective...

Tom

[panchovisa]

Tom, I just haven't found any ready made braces I like. Guess I'll make my own.

[preith]

Here are a couple of pictures of my carb vents... It's the little black L tube to the right of the jet cover. I also included an internal shotvso you can see the baffle. This was all done by Rebello and I can't fully explain how it improves things, but it does seem to work! (as is evident by the blue tint of the race gas on the carbs)

Tom

Thanks for the photos. It looks like they did in fact epoxy shut the bowl holes as well.

[tholt29]

Oh yeah! That's the ticket! I wasn't even looking down there. The vent holes under the jet cover are epoxied shut.

Ya see what happens when you let other people fix things for you? You miss out on the details!

Tom

[ctomkins]

So the idea is to have the vent hole in that baffled compartment.

I wish I had a better grasp on the sidedraft carb situation.

This is classic black magic story of who really knows how and why it works.

[preith]

So the idea is to have the vent hole in that baffled compartment.

I wish I had a better grasp on the sidedraft carb situation.

This is classic black magic story of who really knows how and why it works.

Jetting may fall into the "black magic" realm but this is pretty straight forward, or at least to me. Basically the holes which are epoxy'd shut were originally the vent holes for the float bowl. This simply keeps the bowl from being pressurized and allows fuel to flow in. What happens under high g-load right handers is the fuel sloshes over to that side, comes up through the holes and then flows over on top of the jets. This causes an extreme rich situation because the air jets are being blocked off completely.

[jmortensen]

Thanks for the discussion guys. I've had this problem as have a bunch of my friends with Mikunis. I messed around with my float level quite a bit to fix, but this seems like it's so easy to do that I'm definitely going to do this mod as well.