I had gas leak at the base of the Monojet Rochester carb on my 292 GMC. Fuel soaked the bottom of the carburetor and the exhaust pipe. Needless to say this is not good. I’m not sure if the engine is a keeper so I hesitated on spending money on a rebuild kit or carburetor until I knew where it leaked why the sudden change. Found there is an open p***age for the accelerator rod from the float chamber that allows fuel to spill out the bottom. Did some research and found the leak was likely attributed to float level. Not a lot of Inline carb info so I thought I would p*** this on. http://67-72chevytrucks.com/vboard/showthread.php?t=551485 "Without knowing where it's leaking from, I'd say the first thing to check is your float level. I don't recall off the top of my head what it should be on a monojet, but the little paper that came with the kit should have a listing for it. Also, if you have the old black nitrophyl float in there, they absorb fuel and get heavy, swap it out for a br*** replacement." I lowered the float level and it stopped for a while and then began leaking again and I have the old black nitrophyl float which is mostly likely the cause of the problem. Looks like a $10.00 fix.
Stick a fingernail into the float toe, if gas oozes out it's soaked and too heavy. We used to see if they lit with a lighter but that seems a bit dangerous these days
The leak quit long enough to move the truck a hundred feet to get under roof; a garden hose nearby in case of fire. Thanks for the tip on checking the float for saturation. Is this one of the problems created by newer fuels? The fuel in the bowl also looked dark when I adjusted the float. To keep the truck safely drivable, I ordered a new br*** float from Mike’s Carburetor Parts, $9.95 and $3.06 shipping. I got the truck about a year ago and the valves/ lifters were very noisy and the oil looked like brown PA crude. I changed the oil, adjusted the valves, ran the engine moving it around in the driveway to work on it and it has quieted down considerably. It will probably be more economical replace the engine if a road test reveals it needs rebuilt.
I like the 292s l drove one in my 66 pick up for 14 years.I worked that truck hard it never left my stuck any where and in 14 years just did tune ups and oil changes one water pump never had to open the motor up.miss the old girl sold it to a friend for the motor he wanted to put it in a 62 nova to race boy was that sob fast after he rebuilt it i would rethink getting rid of it for another motorthey can be built to run just as good as any v8
I'm trying to be optimistic, it has good oil pressure and appears the noise is valve related. Hoping it is just varnished up lifters that will begin working properly when heated and running under load. I consider my 292 (1973-1974) an upgrade, almost original-kind of like upgrade to 12V. I p***ed up an opportunity to get an original 270 for the '57, I have a 283 and 350 SBC I could use but believe I will stay with an inline six. Of course a proper V-8 would be a Pontiac but the truck was original with a 270.
Please dont use a garden hose to put out a fuel related fire, you need a pkp / powder fire extingquisher.. for a cl*** B fire. Do some research for safety sake.
same issue here 2 weeks ago. rebuilt carb< still happened. After tearing carb apart 3rd time, noticed br*** float had fuel in it causing carb to overflow into throttle plate. $18 carb kit , $ 11 float, 1 hr labor. Go to an Oreileys Auto and look in the "Walker" parts book. They make the rebuild kit and float. V
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