Need engine help loosing my mind

[eromasik]

Alright so long about Christmas time the waggy started to idle rough and was getting worse mileage than usual. It turned out the catalytic converter was shot. So replaced it with a new flow through cat and eliminated the air injection at the cat. It still wasn't running right so decided to rebuild the carb, found blown power valve. While it was down went ahead and replaced the thermostat, fuel filter, coil pick up in distributor, and some miscellaneous hoses. Got it all back together and it ran amazing for three days and then back to rough idle, slow take off, and died a few times at lights. So off came the carb all apart again, and again blown power valve. Rebuilt carb again, installed it idles great, except the minute you put it into gear it idles like trash and you can audibly hear a vacuum leak. What gives??? Any ideas greatly appreciated. Starting to lose my mind a little!

[addicted]

Spray some carb cleaner around the base of the carb and the vacuum hoses. When it sucks the cleaner in it will change the idle and you'll know where the leak is at. I had a 2150 that did the same thing with the crap idle in gear after a rebuild. Turned out the top of the carb was warped where it sat on the main body. I used a rag to help seal the air leak to find it.

[eromasik]

Thanks for the carb cleaner idea. I tried propane but got no where. I just can't figure why being in gear would cause such a change in idle. I would think if the carb was warped or the like that it would idle crappy all the time. Once it's up to road speed say 20 plus it's smooth as can be, or if its in park or neutral it idles just fine. What is really wild is the audible gas escaping sound it makes when put in gear. It's like you cracked the valve on an air tank.

[babywag]

Cracked plastic phenolic carb spacer. They get brittle w/ age and if it's old, and you r&r the carb a bunch they crack easily.

BJ's has them in stock for pretty reasonable.

[eromasik]

I replaced the spacer with a new one when I rebuilt the carb.

[serehill]

Well

Don't assume it fixed it

[babywag]

I replaced the spacer with a new one when I rebuilt the carb.

Not there can only guess....if you can hear it should be very easy to find.

[Carnuck]

Find a wall, tree or something solid you can park against and put it in gear (I put a wheel chock so it won't roll if it stalls) then see if you can find the hiss. Power brake hose maybe? Not all spacers are the same either. Some leave a spot open. If the AIR pump is still on there, the valve will open when you put it in gear if the other stuff is still attached.