Problems with Vacuum Secondaries on 12a Nikki Carburetor
08-02-05, 10:51 PM
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Problems with Vacuum Secondaries on 12a Nikki Carburetor
Hello,
I have an 85 GS Rx7. I put a 13b race engine in. To help break in my engine, and partially because of a lack of funds, I have a stock 12a Nikki carburetor ontop. It came off of my friends 1978 Rx7 (same as 1979). So the carburetor is a stock, rebuilt 12a Nikki carburetor that was working perfectly on his car right before he put a 13b REPU carb on his engine. Problem: I can not get the secondary barrels to open up. First of all, I can look down in the carb, and increase throttle to high rpms, and they stay closed. There is almost no power to speak of. And, when I use high rpms, or am on the freeway from 70-80 mph (3-4,000rpms), the engine temperature increases from 190 to 205-210. I suspect this could mean my engine is running on a lean mixture. I figure the problem is either an internal vacuum leak inside the carburetor, or a leak of air getting in, so there is not enough negative pressure to pull on the secondary vaccum. All of the smog equipment is not hooked up, so there is not much to look for, as far as leaks. A friend reccommended taking carb cleaner spray, and spraying it around different areas of the carb and intake manifold. Purpose: if there was a small leak, the rpm would have increased, if there was a big leak, then the rpm would have dropped/stalled. I sprayed all over, and no changes to the rpm were notable enough. I have hit a brick wall, because I can't find an external leak, and I would have guessed the internal workings of the carburetor would have been great since it was just working on my friends car. I would greatly appreciate any advice, knowledge, apprehensions, or help you can give me. Thank you.
I have an 85 GS Rx7. I put a 13b race engine in. To help break in my engine, and partially because of a lack of funds, I have a stock 12a Nikki carburetor ontop. It came off of my friends 1978 Rx7 (same as 1979). So the carburetor is a stock, rebuilt 12a Nikki carburetor that was working perfectly on his car right before he put a 13b REPU carb on his engine. Problem: I can not get the secondary barrels to open up. First of all, I can look down in the carb, and increase throttle to high rpms, and they stay closed. There is almost no power to speak of. And, when I use high rpms, or am on the freeway from 70-80 mph (3-4,000rpms), the engine temperature increases from 190 to 205-210. I suspect this could mean my engine is running on a lean mixture. I figure the problem is either an internal vacuum leak inside the carburetor, or a leak of air getting in, so there is not enough negative pressure to pull on the secondary vaccum. All of the smog equipment is not hooked up, so there is not much to look for, as far as leaks. A friend reccommended taking carb cleaner spray, and spraying it around different areas of the carb and intake manifold. Purpose: if there was a small leak, the rpm would have increased, if there was a big leak, then the rpm would have dropped/stalled. I sprayed all over, and no changes to the rpm were notable enough. I have hit a brick wall, because I can't find an external leak, and I would have guessed the internal workings of the carburetor would have been great since it was just working on my friends car. I would greatly appreciate any advice, knowledge, apprehensions, or help you can give me. Thank you.
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