308 carb removal

Nothing special. Just make sure you mark where the the threaded rod-links go (even though they both have R & LH threads, one is longer than the other) and that's about it. Write down which carb# goes where (remember they're identified. eg: 40DCNF45, 40DCNF46, 40DCNF47, etc... Yours are probably different numbers but in any case, its the last two).

I find it difficult to undo the nuts that are under the float bowl area, so be patient with those (stubby wrenches will be a big help). You'll find that as you reach the end of the stud, the nut will jam against the float bowl, so you'll have to pull up on the carb to make clerance... Don't drop the nuts afterwards when they come off the studs!

 

Peter
In general, how smooth were the intake manifold runners when you pulled the carbs? Do you think a fine hone or some careful port matching would improve flow? Caribou found a 7 BHP gain from the ex port - manifold matching.
Philip

 

Hello Mike
I have had my carbs off twice now, take a good digital pic of the setup - its worth a thousand words. Just be careful not to drop anything down the intake runners. its all pretty straight forward in the removal, i know there is a sequence to which carbs get removed / replaced, but its been a while. the sequence just makes getting to the carb holddown nuts easier. take good pics of teh linkage.
john

 

I removed the left side carbs first, nearest to the oil filter. Then it made it easy to get the others off. I video taped mine just to show how to do it. I pulled out the clevis pin and unscrewed the fitting to remove the linkages from the carbs.

 

The sequence is essentially the most difficult nut to remove goes back on first. That is because you need to install the nut while holding the carbs up by 1/4 inch so the nut will clear the fuel bowel. If you install the other nuts first, there is no room to lift up on the carbs

 

Nicely finished actually, I'd guess maybe done with 80 or 120 grit, thereabouts. Matching was bad, both of manifold and the gasket stuck out in a few places too. Definite improvement could be made there, keep an eye out for it.

 

I am actually doing my carbs at the moment on my 308, and I have found the following:
The intake runners were too smooth for proper fuel mixing (maybe that's original, or maybe someone got to it before me).

The port matching from carb to manifold, and manifold to head, were off only on one side of the port diameter (how odd, they match on one half of the circle, and off on the other).

So my plan is to match the port on the carb/manifold side, but taking some metal of the manifold opening.
As to the manifold/head side, I am abit conserned taking metal of the head side, as I want the port flow to go from large to small as it gets to the valve opening.

Does anyone have any opinion on this?
I want to keep the flow diameter the same (ie large to small to keep the are velocity increasing), but want to get rid of the ridge in the flow path that is the manifold/head interface.

Also I will be finishing off the port walls with 40 grit, as the intake runners are so short, it needs all the mixing it can get

 

You have to pull the small cotter pin out, and using a screwdriver, unscrew the big "grub" screw that was being held by the cotter pin. Once you do that, the shaft with the nut on it that has cylindrical assembly, has a ball that fits into it, which will then pop out.

voila, disconnected.