Paul said: "In addition, I'd put a weighted tube into the bottom of your tank, and draw out some fuel and take a look. Most of the junk is down at the bottom, and you may want to just pre-empt the clogging by drawing out as much of that junk as possible."
Hi Paul, that is exactly what we did last summer. We bought the boat and it had perhaps 100 gallons of fuel aboard. We didn't know at first that some of that gas was probably 20 years old! We did not like the smell of it however, so we pumped about 50 gallons of it out and disposed of it, and added about 80 gallons of new fuel (carried to the boat in 5 gallon gas cans!). It looked to us like we got most of the varnish-balls out of the tank bottoms while we were pumping out old-fuel, but later we found that there is still a lot of clumping-looking junk floating around in the bottom of the tanks.
While our filters are fine porosity (30 micron), they are huge Racon filters with about 1 quart size housings. I'm sure the previous owner added them when he found he was getting the smaller stock filter clogged during his annual "engine running" at the dock.
Yesterday we got a break in the weather, and took the boat for a cruise. After a half hour of crusing the S/B engine quit, and although it would restart and run at higher RPMs, we couldn't keep it running at low RPMs after that. It acted like a carburation problem, and/or a major vacuum leak. We didn't have time to diagnose the problem. I will order carb rebuild kits, and if that doesn't work out I may order Edelbrock marine replacement carbs (about $350 each). I think I need to eliminate the possible fuel-system problems one part at a time. As you-all may know, Edelbrock makes the current version of the old Carter AFB carbs.
Anyway, we are getting pretty good at bringing the boat back on one engine -- lots of practice in the last 6 months!
[Me (left) and co-owner Jim after getting back to dock on 1 engine yesterday]
Best wishes, Curt....
1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.