Gas leaking from prop

Dr. Jimbo

Recruit
Joined
Jun 9, 2009
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4
Noob here. I did a search of this problem and didn't quite come up with the answer.
I have an '86 Evinrude 20 hp that hasn't been started in a couple of years. In preparation for selling it, I replaced the gas and fired her up. She seems to run good enough but a few hours after I shut her down, I noticed gas dripping out by the prop and gas in the motor housing. Figuring it was sticky float, I pulled the carb and checked the float mechanism. It moves freely and the little pin moves up and down freely. There is no liquid in the plastic float (I don't think it's hollow, it just seems like lightweight plastic). There wasn't sun beating down on the boat, but there is positive pressure in the system when I disconnect the fuel supply line from the motor. After putting everything back together and tightening down the fuel line under the carb, now it only leaks by the prop (I suspect that it was also leaking at the fuel line because after tightening it, there is no fuel in the housing).
I did read in one thread that the fuel pump diaphragm could be cracked. I did replace that a couple of years ago. My boat has been sitting outside for about 2 years with the fuel line disconnected. I'll have to open up the fuel pump when I get a chance. I may have answered my own question there but does anyone have any other ideas what it might be?
Thanks in advance for your time and help,
Jim

BTW, I was wondering if it takes a long time for pages to load for you. It takes 3 to 5 minutes for a page to load on this site for me. I frequent a car forum and pages load in a flash. I have cable internet and this is the only one that takes so long. I'll see if it does the same on my work computer tomorrow. It's taken me quite a while to search relative posts and I'm glad I've finally gotten to the point where I can ask my question.
 

jay_merrill

Vice Admiral
Joined
Dec 5, 2007
Messages
5,653
Re: Gas leaking from prop

Since the exhaust exits your motor at the prop, what you are seeing may just be excess fuel mixture. Your problem could be as simple as an overly rich mixture. It could also just be normal combustion byproducts. If you actually have raw fuel coming out, I can't imagine that your engine could be running very well.

I am experiencing the same speed issue at the moment. The slowness of the site is probably due to issues with its server. Iboats has experienced rapid growth lately and the server has been overloaded at times. My guess is that the site admin is working on something to upgrade the system.
 

krogie

Petty Officer 2nd Class
Joined
Jun 3, 2009
Messages
107
Re: Gas leaking from prop

sound like a carb problem to me , my 85 used to leave a gas/oil mixture below it on the concreate untill i rebuilt both carbs and had a coil on its way out.
 

Dr. Jimbo

Recruit
Joined
Jun 9, 2009
Messages
4
Re: Gas leaking from prop

Jay, the gas drips out between the prop and the bottom end after the boat has been sitting and makes a small puddle and eventually stops some hours later. She's running good, so I don't think the mixture is too far off. I replaced my coils a few years back and they probably don't have more than 15 to 20 hours of use on them (you can see why I'm selling the boat, I'm not using it). I'll try to check the fuel pump diaphragm in the next 2 days if I get a chance.
It's been a fun boat when I get her in the water. It's a Vaporvette. I think it's 14' and it's like the go-kart version of a speed boat. Once I get the fuel issue figured out, she's going on Craigslist.
Thanks for your help.
Jim

BTW, server is much, much faster today!
 

Dr. Jimbo

Recruit
Joined
Jun 9, 2009
Messages
4
Re: Gas leaking from prop

Fuel pump diaphragm is all blistered but I don't see any cracks or holes. I guess it's time to change that and see what happens.
 

Dr. Jimbo

Recruit
Joined
Jun 9, 2009
Messages
4
Re: Gas leaking from prop

Thanks for all of your help. Rebuilt the fuel pump and no more leaks. Yea! Now it's time to sell.
 
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