We've got a 1983 Pro 7 that we race with Cal Club (SCCA) in Southern California. We're attending to a few maintenance items during the summer "break" and thought we'd rebuild the carb.

I have the Mazda shop manual (very dark images making it difficult to see the details), and have resouced several articles from the Club's web site (thank you very much).

I have two questions today:

1. I have seen conflicting information on whether or not small washers are placed under each Primary and Secondary Main Jet (4 total). We've removed these jets from the carb in our race car and there weren't any. In looking at reference materials I see washers shown. Which way is it? And does it make any difference if we having been running without?

2. In the rebuilt kit, we got the diaphram for the acceleration pump (the small one) but the larger secondary diaphram was not included. What does this larger diaphram do and how often should this be replaced? I haven't found this diaphram on the internet yet. I can tell you that after several track sessions we will loosen the four set screws and we can "drain" a little bit of gas off. One of our local tuners suggested that we do this to eliminate pressure behind the diaphram.

Any help on these two points would be greatly appreicated. Thank you for your help!


Eric

 

I think you're supposed to use a washer under the jets in Nikki carbs but not in Hitachi carbs.

Don'y worry about the secondary diaphram. Just reuse it. Or if it's causing problems, eliminate it and go mechanical secondaries. Search this forum under the name Sterling for a nice write up.

 

Good morning everyone! Still hoping for your help... please leave me some input.

Thank you!



Eric