20 year old varnish in tank 208

[rmf4grady]

I have posted here before related to my ongoing work on my 2000 208. Replaced the transom, all electrical wiring and found a nice
2020 DF 175a zuk with 200 hours for 7K to replace the yamy 2 stroke. Everything was going great until I took it on a shakedown cruise.
When I started working on the boat the tank was emptied, and I ran the motor on an external tank. I started putting gas in the below deck tank and it
was going great so I figured not much varnish. I put 40 gal in and it ran great, but I still hadn't put the boat in the water. Well first trip out
and put it up on plane, it sputtered to a stop and was towed home. After some troubleshooting, I found the gas was crap, filled with varnish.
Is there any way I can clean this shit out or am I just screwed? I'm going to put a small external tank on it tomorrow and hopefully it will run smooth.

Any ideas?

Rich

 

[Hookup1]

Do you have an inline filter before the engine? What has it collected? Are you sure it’s not water?

Ethanol is a great solvent. It will free up varnish and dissolve fiberglass tanks. The sludge can destroy your new engine too.

Pump some fuel into clear container and let it settle. Put a photo up.

 

[seasick]

Was the gas you out in ethanol?
I think there may be water in the tank since your motor died when getting on plane. In that case the bow is angled up and the gas and water move aft in the tank in effect making the water level deeper. Now the motor may be sucking mostly water.

To check, dump the contents of the water separator/main filter into a glass jar and let it sit for 10 or 15 minutes. See if you have water on the bottom of the jar.
You didn't say if there was old gas in the tank already. It is possible that you had bad/stale gas.
When you added 40 gal of gas, what did the fuel gauge say. Ft that hull, 40 gallons is half a tank.