Chrysler 318 rpm surging issue

Hi my name is Jeff, I'm new to this site and was hoping to get some advice. I recently purchased a 1962 century resorter with a chrysler 318 in it. The valve covers say m318b but the brass plate on the engine says 318 bl. Not sure which model number to go by but anyway here is my issue. I took the boat out for the first time and it ran great, no issues. Parked the boat at the dock and went to take it out the following weekend and started having a problem with the idling. The engine won't idle under 1000 rpm's and when is is idling this high the rpm's will surge up to like 1400-1500 and drop back down. I originally thought it was a fuel issue so I changed both fuel filters and cleaned and rebuilt the carb. Put everything back together and it's running the same. Anyone have any ideas? Thanks for the help.

-Jeff

Ethanol contaminated fuel. Having similar trouble.

Try this: Get it running, then shut off the gas to the carb and run it dry. (Work hell out of the throttle as it runs out, to suck every drop out--important!) Repeat, then see if that helps.

Another Jeff

Thanks for the info Jeff. Let me ask you something else and see if you still feel the same. I did drain the old gas when I put the boat in the water this year and put in new gas. I also added sea foam to the fuel. I took the boat out after I did this and it ran fine. I docked it for a week and when I took it out the next weekend I started having the surging issue. I put all new plugs in it, changed the fuel filters, and pulled the carb, cleaned it and rebuilt it. Based on this, do you still think it could be an ethanol issue? If so, if I do what you said earlier and it helps should I drain the fuel again and put new fuel in or can I just add some dry gas/ fuel additive?


thanks,
jeff

Yes! I pulled 4 gallons of gas from each tank and it was clear (checked it in clear bottles). I'm all set, I thought, but out on the water the "White Gook" was still there and has made boating a nightmare; stalling, rough running, back firing... (Damn the politicians to hell over this!) And when we made a sudden stop last week (long story) the problem got MUCH worse. Why? The gas sloshing forward in the tanks must have loosened up more "White Gook" to get sucked in.

Apparently, this crap does NOT simply sit at the lowest point in the tank, so it can be pumped out. I've heard of people rocking the HELL out of their boats to do this and having success. My point is that, simply pumping MOST of your gas out, will not get rid of it all--it clings to the tank bottom and walls.

Damn the politicians to hell over this!

Jeff

PS: Furthermore, the build up of "White Gook" is cumulative: every year more of it builds up.

Thanks for the help Jeff, I'll give it a shot and see if it helps.