jbizub5192

I have done carb rebuilds in the past so doing the rebuild is nothing new to me. I haven't dealt with metering rods before though. I rebuild my whole sterndrive so I am mechanically inclined. At this point im going to leave the metering rods alone and just do the rebuild and see how it runs. If it still runs rough then ill have to do the rods. Thanks for all the help everyone!

BeakBoater35

If you were able to visually spot the difference in metering rod diameter where they pass through their respective jets I would seriously consider replacing the rods. Same goes for their jets if they are removable.

Budman II

iTrader: (1)

From the sound of things here, I think we are talking about a Rochester Quadrajet carb. The primary and secondary metering rods on these carbs almost never "wear out". If they do, then something is seriously wrong. They don't really make much contact at all with the jets that they ride in - it is more of a situation of restricting an orifice rather than completely closing it off, if you look closely at the operation. Many of these rods are intentionally stepped, which could be confused with wear. Unless you have made major changes to the operating characteristics of the engine, i.e., displacement, cam timing, much better heads, then there should be no need to change jets or metering rods. I would simply go with a good MARINE grade rebuild kit, thoroughly clean it in carb cleaner and blow out all the passages, and reassemble it according to the directions in the kit. Keep a close watch on the float adjustment, because they are quite sensitive in this area, and unlike a Holley, you cannot change the float setting without taking the main airhorn (top) off of the carb.

If it was idling rough and running rich at idle and low speeds, and you have changed to a cam that doesn't draw as much idle vacuum as the stock cam, then it is possible that you need to change to a lighter (i.e. weaker) main power valve spring. This is the spring that rides under the plunger / hanger that holds the primary metering rods. It is pulled down by idle vacuum to hold the primary metering rods down (closed). If there is low idle vacuum, then it will not be able to overcome the spring that is forcing the rods up off of the jets. Changing the rods or the jets will have little if any effect in fixing the rich condition if this is the case.

Good luck!

jbizub5192

Thanks for all the info! Im pretty sure I have a weber 4 barrel carb though. It was actually starving for fuel because if I put the choke on my rough idling would clear up. Is weber more sensitive with the rods? I have some pics of the carb below. Thanks again

jbizub5192

jbizub5192

FIXX

iTrader: (2)

when you shut the choke whyle the engine is running and it still runs you have a vacume leak,the engine should die...

And that is a webber carb .......

jbizub5192

I thought it was a webber because when I enter my serial# for the parts catalog from mercruiser it showed 4 barrel as webber and I believe the 2 barrel was Rochester. I dont remember if I closed the choke completely or just part way. If I did close it fully then ill check into the vacuum leak issue. Is there a common spot for a leak on this engine? Thanks!

FIXX

iTrader: (2)

intake gasket,,if the bolts are loose then suspect the intake gaskets..

jbizub5192

Ill have to take a look at the bolts and see if there loose. Thanks