Gas problem on 1981 Mercury 40 HP Outboard

[jathomps04]

I wanted to run something by all of you smart people real quick. <br /><br />I have a 1981 40 HP Mercury outboard which has 2 cylinders and the super bowl carb. I'm having a gas problem that I think I've nailed down and I need to know if everyone thinks I am right. <br /><br />Basically, the engine will fire and run fine when I spray a oil/gas mixture directly into the carb but won't run when I just try and start it normally. I emptied the old gas out, replaced it with new, mixed it and made sure it was pumping gas into the engine. Then I made sure that gas was getting to and through the fuel pump. Everything was fine up to this point. Then, I found out that gas is going into the carb. I know this because when I took it off it was full of gas. <br /><br />I'm thinking that what I should do is dismantle the carb completely, soak overnight in B12, make sure it all looks clean and then try to start this beast again. <br /><br />Thoughts?

 

[JB]

Re: Gas problem on 1981 Mercury 40 HP Outboard

"make sure it all looks clean "<br /><br />Not good enough. Blow out all those tiny passages, particularly the orifices into the carb throat and the jets.<br /><br />That should put you in good order.

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Ok. Thanks for the hint. I'll work on it and let you know the outcome. <br /><br />Thanks again!

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Update: While taking the carb apart I noticed that the gas, or liquid that was left in the fuel bowl was a milky white substance. Does anyone know what this could be?<br /><br />Note: The gas in the take is fresh and looks fine.

 

[JB]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Water. <br /><br />No wonder it wasn't happy.

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

That's what I figured. Where do you think it could be coming from? The tank?

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

After taking the fuel pump apart and cleaning it thoroughly I found no cracks or leaks where water can get in (Water circulates around the fuel pump on this motor.). I suspect I just got some rain water in my gas tank. A test fire will let me know if that is right.

 

[Jan Z]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Ethanol attracts water, use a fuel stabilizer, do a search on ethanol. I had the same problem with an new 40 Yamaha

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Well, I've already cleaned my tank out. I was thinking about rinsing it with a little gas once and then refilling it with new, fresh gas and going from there. Do you think that will work?

 

[Texasmark]

Re: Gas problem on 1981 Mercury 40 HP Outboard

Your tank breathes so it will ingest moisture. Alcohol and water combine and make a jelly goo that clogs things up. BTDT...in one of my boats and in my windshield washer on the truck.<br /><br />Looks like we are going to have to deal with ethanol, those of us who never used it before; course I hear that the midwest folks have been using it for years. So what's their secret? Dry climate? Water separating fuel filter?<br /><br />Maybe somebody will respond.<br /><br />Mark

 

[jathomps04]

Re: Gas problem on 1981 Mercury 40 HP Outboard

I just wanted to drop in and tell everyone how things went. <br /><br />I was able to replace the gaskets on the fuel pump, clean it out, and clean the carb and get it all put back together. Then, it started! <br /><br />However, after it ran for a few minutes the flywheel actually caught a wire and tore it in half. This caused the engine to die and the spark plugs weren't getting any fire to them. I replaced the broken wire but still no fire. <br /><br />I guess my next step is to pull the flywheel and see what damage has been done underneath. <br /><br />Thoughts?