Disconnecting fuel line

[grbeasley]

I have always owned a 2-stroke outboard where the oil was added directly to the fuel. My dad always told me that I should disconnect the fuel after every use and run the engine until it died. I did that and never had a problem with the engine. Now I own a 1994 Mariner 40Hp with oil injection. Should I continue to disconnect the fuel line? Or will that cause problems with the oil injection system? Your responses will be greatly appreciated.

 

[5150abf]

Re: Disconnecting fuel line

Welcome to iboats, I hate to tell you but your dad was wrong, it is bad to do that because 1 cylinder always runs out of gas before the other which means the engine is running without oil in one of the cylinders.

There really is no reason to do that at all unless you are going to store the boat for a period of time and then you should drain the carbs at the float bowl not run the engine dry.

So the answer is no don't unplug the gas, again there is no reason to.

 

[Silvertip]

Re: Disconnecting fuel line

Also, the carbs do not run completely dry. The engine dies long before that. Run a fuel system treatment like SeaFoam, Stabil, Startron or any of the others and you don't need to worry about fuel system issues.

 

[JimS123]

Re: Disconnecting fuel line

Yup, they don't run completely dry, but they at least drain a little bit.

My Grandpa (and my Dad) told me the same thing, and I have never found either one to tell me something wrong. I have a number of motors, many bought brand new and have ALWAYS pulled the plug and run her dry at the end of each boating day. As an example, I routinely run a 1968 9.5 Evinrude that has NEVER once been put away without runnin her dry. After 42 years it doesn't seem to have hurt her any.

A 2-stroke is very oily internally. I find it hard to believe that a few seconds without oil at the end of the run will hurt it any. Not enough time to burn up all the oil that may be left. Besides, on startup, it gets a good squirt right at the beginning again.

I religiously use Stabil in the gas on the last outing to treat the gas tank and whats left in the carb. In contrast, my Dad doesn't believe in that "chemical crap" (LOL) so he just drains the tank and lets the engine run out the rest. Even with his procedure, he's never had a problem either.

Seems to me there is more than one way to skin a cat, and maybe if someone tells you their way is the only way its probably best to get a second opinion.

 

[5150abf]

Re: Disconnecting fuel line

My question is, why do you do it, because your dad told you too or is there a reason behind doing it?

I don't see anything beneficial coming from it, I just never understood why anyone would do it.

Gas only causes a probelm in the carb if it left to sit for long periods, if you use your boat even twice a month it will be fine, espacially if you use Stabil.

 

[grbeasley]

Re: Disconnecting fuel line

I did it because it seemed logical that the gas would evaporate and leave the oily gunk to clog things up. And, as I said, it seemed to work just fine with my previous motor. I don't get to use my boat that often. It has sat for the last 6 months or so during hunting season. For some reason, the deer seem to prefer staying in the woods instead of the river.

 

[Home Cookin']

Re: Disconnecting fuel line

I think the only answer is "it depends." usually the best answer for baot questions. I've seen temperamental engines that won't restart a few weeks later if you don't run out the gas. I can't explain why, but I like the notion of running out the gas on a small motor (<25 hp) but not a larger motor. I also wonder if the left-over gas is better than salt air.
But my practices go back 40 years, plus my dad's on top of that. With ethanol, I think it's more important than before to run gas out of a small engine, and treating the gas is essential IMO.

 

[grbeasley]

Re: Disconnecting fuel line

These replys have made me think a lot about how my engine works. Now I have more questions than answers......Where does the oil injection system pump the oil? Is it directly into the piston or into the carb?

 

[JB]

Re: Disconnecting fuel line

This action started waaaaay back when most outboards were what we would call low HP and went home in the trunk or in the pickup bed. That way the carb didn't stink up the vehicle with leaked gas.

Then it was done on small outboards that stayed tied up to the dock at the summer cottage and might not be used for several days at a time. Less justification, but still it was "the way granpa told me to do it".

I continued to do it on small, single carb outboards for about 50 years and suffered no penalties.

On the other hand I completely agree with the theory of why not to do it. I just haven't ever seen any damage caused by doing it, even on big, multicarb outboards.

This may be comparable to smoking. We all know it is bad for us and are told endlessly that it will kill us, yet many of us smoke for 60 years with no sign of lung cancer. Some even do it and retain a healthy heart.

If I still had the fleet of Whalers I would run single carb engines dry and drain the bowls on multicarb setups.

EDIT: I am still old fashioned. I would not run an oil injected or DFI engine dry. . .ever.

 

[rickdb1boat]

Re: Disconnecting fuel line

These replies have made me think a lot about how my engine works. Now I have more questions than answers......Where does the oil injection system pump the oil? Is it directly into the piston or into the carb?

Fuel and oil are mixed at the pump. The pump is both a fuel pump and an oil pump combined into one. The blend of oil and fuel is sent to the carburetor and then into the combustion chamber