1987 318 Tuning with Summit Carb

[sarguy01]

Something very odd about this carb. Post #67, idle tubes measure 0.053" ??? Surprised more folks have not commented on it. Or, is the restriction in the top of that thin tube? Check with drill bits or thin wire if drill bits are not long enough.
A general purpose over the counter 600 cfm carb, no matter what brand, you would expect to see an idle jet in the 0.028-0.035" range. Using 033 as datum, 053 represents a 158% increase in area, more than 1.5 times. Something is not right.

The idle jets in the spec sheet showing as 0.046". I wondered why that size would be given because they are not replaceable; the idle feed is the brass tube, but the restriction may be at the top of the tube, as discussed.

I believe the 046 refers to the Economizer jets & I believe they are two replaceable jets shown in the red circles. They are also part of the idle cct. Econo jets are always above the fuel level, as these are. The Econ jet in the 6000 series TQs are in the 046-048 range & also in some AFB carbs. The econ jet supplies mixed air + fuel to the t slot & idle mixture screw port, for idle & low speed cruise. It is a jet that might need to be changed so it's position in the cluster makes sense [ to me ].

Pic in post #53 of the booster assy. I see holes in the casting that are probably air bleeds. Not sure about the brass jets.

I'm calling Summit today. Hoping for them to help with tech or just take this thing back. If I do send it back, I'll take a look down that tube.

Those idle jets / bleeds came as a .043. The engine ran with the speed screw all the way in and mix screws all the way in. I changed them to .046, in an attempt to lean out the carb. It now runs with the mix screws all the way in, and the speed screw just 1/4 in.

I don't think an out of the box 600 carb should give me this much trouble adjusting. My timing is sitting at 14 degrees, which seems to be the best spot for it. Can't find any vacuum leaks. If I throw the Eddy back on I get normal adjustability at idle. So either I'm missing something with the Summit carb or it's defective.

 

[RustyRatRod]

One thing. I don't think I'd mention to Summit you've had the carburetor splattered all over the work bench. I would simply tell them no matter what you did, you couldn't get it to run right and it must have an internal vacuum leak. You should have a return form that came with it in the box. You really don't even have to call them if you do. Just fill it out and send it back. But if you do call, they will very likely send a call tag so you don't have to pay return shipping.

 

[Icetech]

I hope they replace it for you and the new one just works.. having to go through all that is bullshit...

If you have to change it, i got a speed demon for around the same price, bolted on and it ran great out of the box (although not many miles on it yet) might be worth a try for you.

 

[RustyRatRod]

I hope they replace it for you and the new one just works.. having to go through all that is bullshit...

If you have to change it, i got a speed demon for around the same price, bolted on and it ran great out of the box (although not many miles on it yet) might be worth a try for you.

I don't know why, but I thought the chick in your avatar was dead somehow, but she's not. We still gotta shot at it. lol

 

[sarguy01]

I hope they replace it for you and the new one just works.. having to go through all that is bullshit...

If you have to change it, i got a speed demon for around the same price, bolted on and it ran great out of the box (although not many miles on it yet) might be worth a try for you.

If I'm able to return it, I'm on the fence about slapping the worn out Edelbrock back on and just getting a refund. I've got too much stuff to work on at the property and just want the Ramcharger running. The Eddy runs good enough.

But, if I decide to get another carb, it will be a Holley or Holley style since it spent the money on a jet kit and air bleed kit.

In my price range, looking at the 4160, Holley Street Warrior, Demon, and the Quickfuel Brawler.

 

[Icetech]

If I'm able to return it, I'm on the fence about slapping the worn out Edelbrock back on and just getting a refund. I've got too much stuff to work on at the property and just want the Ramcharger running. The Eddy runs good enough.

But, if I decide to get another carb, it will be a Holley or Holley style since it spent the money on a jet kit and air bleed kit.

In my price range, looking at the 4160, Holley Street Warrior, Demon, and the Quickfuel Brawler.

demons are really.. really bad.... just to save you the headache.. street demon is a different carb is all. Good luck!

 

[sarguy01]

Got a UPS label. Summit is going to take it back on warranty. For now, I'm just throwing the Eddy back on. It ran well enough with that. I've got too much stuff going on at the homestead to try another carb.