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weber questions

hotrod

Donation Time
I am attempting to tune a 38dges weber on my 1725 engine. The carb has 45 idle jets, 185 air corrector jets, and the main jets are unmarked but have an orifice size of .052-.053". Right now the car will start, but won't idle. I don't have a working tach but I would guess that the engine dies below about 1200-1400 rpm. Backing out the idle adjusting screw seems to slightly lowest speed the engine will run at. However, even with the screws out 4 turns, the engine still won't idle. I plan to buy 50 and 55 and maybe 60 idle jets and try those. my questions are: Any suggestions on air corrector jet sizes? And how do I remove the emulsion tubes? I am not sure how they effect tuning, but I see that there are various sizes available. Any suggestions on main jet size? I am not too concerned with them now, but since I have to order the parts, it might be a good idea to get them at the same time.
 

RootesRacer

Donation Time
50s or 55s should be about right, but even 45s should be able to be adjusted for idle with the mixture screws.

My guess is you have a vacuum leak.
 

hotrod

Donation Time
I was afraid that might be. I have had the carb off and replaced the base gasket so I don't think theres a leak there. I will investigate plugs in the manifold. But if it is the manifold to head gasket, how can I tell if there if there is a leak?
 

hotrod

Donation Time
Update. Changed to 60 idle jets. Car now idles and runs. Drove for the first time the other day. I hadn't driven an Alpine in about 40 years. I had one as my first car when I was 15. I don't remember it as being so slow and underpowered. What I do remember was beating the crap out of that car and it never quitting on me. It was about 8 years old when I got it.

I bought jets from Carbs Unlimited. I ordered 55 and 60 idle jets. The 55's they sent were both the larger jet. I called them and they are supposed to send me the smaller jet. Also one of the large 55's is obviously mismarked. I can't visually see the difference between the 45, 55, and 60 jet hole size. But the one 55 clearly has a much larger hole. I don't think I will order from this company again. They also charged me a handling fee to mishandle my order. I saw a company called Rapid Carb on ebay that sells Weber parts. In Rapid City, SD I think. Anybody dealt with them?
 

Robbo

Donation Time
If it helps as a comparison, I have a 47 main idle jet at 2 1/4 turns out and secondary s 50, idles really well at around 900rpm, the main/secondary jets are 130 and 145 with air corrector jets at 175 and 180. I've been told my secondary main should be closer to 160, but seems to run well at 145. This is a 32/36 weber and it runs really well with good mileage and power for me. I also look at the vac off the manifold port with a vac guage to watch its behavior when I'm done and tuning. If its waving irregularly it will tell you a lot about the vac condition. If it's steady at say above 15, then you should be in around the right place I believe but others will be able to chime in if this is a good method to check your engine conditions. There are other things that impact vac, but if its waving around, it is one way to help diagnose a leak. What I've learned along the way with the Weber is tuning takes time. A good approach is start with idle jet tuning, then work through each circuit. If you know someone with a wideband sensor gauge, it will really help. Good luck.
 

RootesRich

Donation Time
I bought jets from Carbs Unlimited. I ordered 55 and 60 idle jets. The 55's they sent were both the larger jet. I called them and they are supposed to send me the smaller jet. Also one of the large 55's is obviously mismarked. I can't visually see the difference between the 45, 55, and 60 jet hole size. But the one 55 clearly has a much larger hole. I don't think I will order from this company again. They also charged me a handling fee to mishandle my order. I saw a company called Rapid Carb on ebay that sells Weber parts. In Rapid City, SD I think. Anybody dealt with them?

I've bought all my Weber jets from Pierce Manifolds. In 8+ years, I've never had a problem with an order. Prices are competitive and no outrageous shipping costs.
 
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