Unplug Myth ?

[Deep V]

I mentioned to my friend that, after I shut off my 2 cycle out board motor, it seemed that alot of oil was coming out of the exhast. He promptly said,"Oh yeah, don't you know, you're suppose to unplug your fuel line from your motor and let it run out of fuel before shutting it down. I found that out the hard way, after my fuel pump diafram blew-out in my hot garage, due to expantion in the fuel left in the lines." I tried it once; it took forever. I'm not convinced. I've since, started mixing my fuel alittle lighter (I was mixing it alittle heavy, just to be safe), but I'm assuming that it was more oil than the motor could burn-off. I'm now seeing a lot less oil after I shut down. By the way, there was no difference when I did the "unplug thing". Could I get any comments on this please.

 

[JB]

Re: Unplug Myth ?

Not a myth.

Works pretty well on single carb, non-oil injected outboards but risky on multicarbs and oil injected because of the risk of running one or more cylinders dry or pumping the carb(s) full of oil and no fuel.

The story about blowing the pump diaphram is pretty far fetched. I don't believe a letter of it.

Burning the carb dry is something that started with small, portable outboards so that they wouldn't drip gas in the trunk or truck bed. Always did it with my little portable JohnnyRudes, but never with a big one.

 

[j_martin]

Re: Unplug Myth ?

I shut off and run the carb dry on all the little 4 cycle stuff around here. It leaves the needle valve hanging open, and I never have a problem with a no start because of a stuck needle, or a flooded situation because the needle valve allowed the gas from the elevated gas tank to flow through.

Unless you're unclamping and transporting a small outboard, it's not needed. If you premix your fuel, it won't hurt anything. If the engine is oil injected, it's a definite no-no.

The only real myth I see in your thread is the notion that adding more oil to the fuel than the specification makes it "richer" and therefore better. You can actually do serious damage to your engine doing that. The same slop that is dripping out after shutoff is trying to burn in the exhaust system and clogging things up. It also tends to foul plugs. It can cause a carbon buildup in the cylinder and pre-ignition with piston damage. It can also increase the fuel viscosity enough to lean out the mixture, causing cylinder temps that threaten the pistons.

my 02
John

 

[Deep V]

Re: Unplug Myth ?

Thanks guys, It makes more sense now.