Draining gas

[lifespan]

1999 Maxum 2100 SC. Recently had carburetor rebuilt. Sill running very rough on cold start. Doesn't take a lot to crank it over. Once warmed up, runs better but has a little miss. Adjusted electric choke as well as idle screw and fuel mixture. Choke closed when cold and does open when gets warmed up. Getting frustrating as It starts to run and start better, then in the morning after having sat a while, runs bad again on starting.

My big question is the impact of old gas. I am assuming that the gas is at least a minimum of one and a half to two years old. sat in a guys garage before I bought it, with a full tank. I probably should have just had it drained in the first place. Doing that tonight.

Should I also replace the fuel filter and I assume the water separator (assuming that is part of the replacement unit or and additional part?

Anyone with similar experience with rough idle and cold start related to gas?

[mmwjr]

Yes replace the spin on fuel filter/water separator. To verify there is water in the gas pour the contents into a glass jar and look for signs of water.

[lifespan]

Siphoned all gas out tonight. Fairly dark, couldn't really tell if there was any water our gunk so to speak. Seemed darker than what I think it should have looked like. Odor didn't seem quite right. Piece of mind knowing gas that I couldn't assign an age to is it. Address fresh gas after and slowly started to run much smoother. Guy who rebuilt my carb siphoned the gas and realized the first needed to be adjusted. After her did that, it ran very smooth.

Now for one of the earlier issues I had posted. One of the risers of the exhaust manifold is running noticeably hotter than the other. My assumption is of course that they should ruin the same temp. Didn't gauge it at all, just by touch. The more I read and research, I keep hearing that exhaust manifold and risers need to be replaced every whatever period of time (years) as part of maintenance. Thoughts on that? I am going to pull the riser to check for corrosion. If present, what else should I look for? Can it be cleaned and put back on? Or should I replace? If I replace the one, should I replace the other? What about the manifolds? Are they just automatically replaced every X number of years?

[mmwjr]

When E10 phase separates there is two distinct layers of gas on the top is a dark low octane gas and the bottom a clearer alcohol/water mixture.

I would get a handheld IR temp sensor and measure the elbows and manifolds first, they should not be exceeding 150 F. If they are original then yes time to replace everything instead of risking their failure which can result in destroying the engine.

If you remove the elbows the water jackets will have rust but its the flakey scale that is the sign of EOL (end of life).

[shrew]

Thread was entitled "Bad Gas" which was the topic for 4 posts. The following 22 posts were about Manifolds and Risers.

I've split the posts to be topic specific.

Manifolds and Risers:
http://www.maxumownersclub.com/forum...rs-5713-3.html