Got the engine Started! Now to trouble shoot odd running patterns

[LemonShark2]

LS2
You're on the right track here. If the fuel is questionable get rid of it. Don't fight with it. As noted additives will not clean up dirty fuel. It what's going on inside the tank that determines engine performance.
Small detail: Marine tanks fill and empty from the top so you won't be able to drain it. What works sometimes is to attach a tube to a stick or dowel with cable ties and leave the tube sticking out from the end of the dowel ~ 2". Then use this apparatus to guide the end of the hose to the lowest corner of the tank while you pump the gas out. Catch some of the fuel in a clear glass jar and hold it up to the sunlight to see how much crud is in it.
If you don't have one already I would strongly suggest a final filter between the fuel pump and carburetor. Available from MMI.

TRUE GRIT

I actually do already have that finishing filter that PO bought, and never installed! I'll put it on after I clean the Carb.

Regarding the Fuel - When I first bought it a few months back, I burnt the old fuel all the way to empty, then added new fuel. Since then, I had the issue of letting about 1-2oz water through, so I drained most of the tank, let the water and debris settle to the bottom of the container, then siphoned only the "fresher" fuel back in.

Sounds like I should just siphon out all of that "Like New" fuel instead of hoping my project did the trick...

[JOHN COOKSON]

IRegarding the Fuel - When I first bought it a few months back, I burnt the old fuel all the way to empty, then added new fuel. Since then, I had the issue of letting about 1-2oz water through, so I drained most of the tank, let the water and debris settle to the bottom of the container, then siphoned only the "fresher" fuel back in.
Sounds like I should just siphon out all of that "Like New" fuel instead of hoping my project did the trick...

The choice is yours to make. You could see how it runs with the "new fuel".
Over time you might make out OK. Maybe not.
A couple of considerations:
There is never a good time for engine trouble. Personally I will not do ANYTHING or tolerate any situation that compromises engine reliability.
When you are out sailing and the wind and seas pipe up it is not a good time for doubts about anything boat related. Been there. Done it. Didn't like it.

TRUE GRIT

[marthur]

Lemon Shark,

Here is my experience with the C-27 gas tank.

I found my tank to be in perfect shape. It was also easy to clean but very hard to remove. On my 1977 C-27 the tank is under the starboard quarter berth and you must remove the engine or cut up the fiberglass liner to remove it--so I didn't.

I have cleaned my tank. The problem I had was water and it got into the tank due to a bad o-ring on the fuel fill. FYI: I would recommend buying a dozen o-rings and replacing one every time you feel a disturbance in the force.

The fuel pickup tube and the gas gauge on my tank were both on large-ish plates screwed to the top of the tank. Removing fuel pickup tube I was able to pump out all of the fuel and then reach in with a rag to wipe down the tank. I took out the gas gauge for a hole to see what I was doing with my arm in the tank. Be ready to replace the gaskets on the fuel pickup and gas gauge. I used rubber gasket material and cut new ones with an exacto knife.

I wiped the tank down, but there really wasn't anything built up on it. It is possible that the times I have used e10 from the local gas station dissolved anything that was there, but the couple of fuel problems I have had have all been water or downstream of the tank.

Good luck,

Mike