The International Cessna 170 Association

During my oil change (C145-2H), I was doing the obligatory engine cleaning and noticed the carb bowl wiggled slightly while wiping it down. Did a leak check of the intake system and decided to spray a little soapy water around the carb as well. Good news is there were no leaks on any part of the intake system. Bad news is there were soapy bubbles at the front of the carb where the bowl meets the body and also around the area where the throttle plunger goes into the carb. The carburetor appears to operate normally. No abnormalities during start or shutdown.

Questions…
Is this normal for these carbs to have a little play in this area?
If the gasket between the body and the bowl needs to be replaced, does that require an overhaul or can just the gasket be replaced?

I’m going to talk with my mechanic tomorrow but just wanted to ask the forum to get other opinions.

Here are a couple pics showing the area that blew soap bubbles (highlighted with yellow):

That plunger is the “accelerator pump” and there’s a replaceable seal that is leaking.

The carb body gasket and the accel-pump seals can be replaced by your A&P without completely overhauling the carb. (or yourself under his supervision, of course.)

It’s not common for the bowl to be loose but it may be that it was not properly torqued initially and perhaps the gasket has compressed further since prior assebmly.

Thanks for the advice, George. I did a little research on my own as well. Came across Marvel’s SB-17 concerning bowl to body leaks. Since I wiped the carb down there is no evidence of leaks, but fuel stains were apparent beforehand. According to the SB, they backed you up by recommending the bowl to body gasket be replaced along with some other instructions such as checking the bolts for security and inspecting the threads for wear. One thing that is interesting is it mentions checking the motor mounts since excessive vibration may cause the loosening that has occurred.

Waiting on my mechanic to work me into his schedule for now.

Here’s a copy of the SB: