Carter Side Draft

[Shannon Boal]

Re series V hot soaks....hafta crank 2,3,4 seconds before it starts and runs normally. I looked in the fuel line at the carb and it was dry. I installed a sleeve of silvered fiberglass over the fuel line from the pump to the Weber Progressive carb. Test drive 100 miles at summer temp 95-100 F, hot soak about the same. It did not hurt, might have helped. The exhaust is wrapped, engine stays cool at 175F while moving. May try a chek valve.... https://www.amazon.com/dp/B08745R7HP?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[Bill Blue]

The carter is working out okay. Got a problem with carpet rubbing against accelerator linkage, making off idle throttle very sticky and abrupt, but that's a different issue. The main issue, and I think the root or the flooding while starting, is the carb float likes to stick, causing gas to run out of the carb. Took the float out of the carb, clean as a whistle and no obvious problems. Don't know what else to do. Drove the car about 100 miles yesterday, the carb behaved after a sticky float produced an interesting issue on startup. Really don't see how gasoline can backflow out of this carb, gasoline flows down out of the carburetor cover plate, into the bowl.

Bill

 

[husky drvr]

The main issue, and I think the root or the flooding while starting, is the carb float likes to stick, causing gas to run out of the carb

Bill,

Knowing nothing about the YH, this is a guess.

Found an online discussion about your over flow issue. The recommendation was that it was probably an issue around the accelerator pump. Might be a seal issue due to a warped cover or most likely a diaphragm that has a porosity issue. It was also mentioned the diaphragm is subjected to manifold vacuum on one side. Is that to a turbo boost feature?

There was also a mention of a book that was at that time availible on Amazon about identifying and tuning the Corvair YH carbs.

I figure you've already discovered this possibility, so it's probably not news. I tried to get a link but was unable due to browser security not playing well with that site.

Hope this helps,

 

[Shannon Boal]

The carter is working out okay. Got a problem with carpet rubbing against accelerator linkage, making off idle throttle very sticky and abrupt, but that's a different issue. The main issue, and I think the root or the flooding while starting, is the carb float likes to stick, causing gas to run out of the carb. Took the float out of the carb, clean as a whistle and no obvious problems. Don't know what else to do. Drove the car about 100 miles yesterday, the carb behaved after a sticky float produced an interesting issue on startup. Really don't see how gasoline can backflow out of this carb, gasoline flows down out of the carburetor cover plate, into the bowl.

Bill

The theory I am working from, in my effort to reduce hot-soak flooding, is this: The fuel will not boil out of the fuel line if it is under some pressure. The fuel pump outlet check valve will hold pressure with hot-soak conditions, but when the fuel bowl boils down the float valve will not hold pressure. When that happens, the fuel in the fuel line evaporates too, into the intake manifold (through the internal bowl vent). The addition of a one-way check valve at the carb inlet makes a small difference; it requires a small forward pressure to open, so it places a small pressure over the fuel in the line which oughta help prevent that boiling dry. I worked on GM carburators (drivability tech in the 70's-90's), and all the Rochester carbs with a filter located in the carb fuel inlet nut came originally with a check valve stuck in that filter. The forward pressure required was a moderate to firm effort blowing through it maybe one or two PSI. So, maybe a one PSI sustained pressure on the fuel in the line will reduce the hot-soak cranking/flooding problem. More testing/driving planned with a check valve.
If we ever invent the perfect carb set-up, Dan R. will answer with fuel injection.....