Deadly Sushi
The One, The Only, Sushi
Anyone hear about or use something called Seafoam? People seem to dump this stuff in their fuel tank, crank case and other places to blow out carbon deposits. Sounds fishy to me.
Running synthetic in an old car will definitely clean things our and will show you every place where it leaks!
The synthetics are very good at cleaning deposits, therefore will expose any "weak" seals, gaskets or places where the goo has held the old oil in.

To start, you can count the 2 engines you got from me...I couldn't begin to count the number of carbs I've taken apart and rebuilt because of buildup, sticking needle valves, sticking butterflies, sticking floats etc., etc.
Many years ago, I worked for a company that installed "water injection" systems into carbs. It helped clean the engine and also reduced fuel consumption and increased power. I'm surprised it never caught on.Heck, if you have a vehicle with a carburetor I have a very cheap method of clearing out carbon in a big hurry. Take the air cleaner off and get a friend to operate the throttle if you can't reach the linkage from under the hood (generally I operate the throttle myself from under the hood) and get you two Dixie cups of water; yup, water. Fire up the car and, after it's up to temperature, slowly pour the water into the carb. As it starts to die, hammer the throttle to keep it running. By the time you've slowly (if you go fast you'll blow a hole in the top of a piston or bend a rod) poured both Dixie cups of water through the system 90% or more of all carbon will be gone.![]()
P.S. That method is generally not listed in any repair manual.![]()