run the fuel out or leve it in after use

[redfish1940]

40 hp 2005 tohatsu with auto mix oil.
Is it best to disconnect the fuel line let it run out till the motor stops or leave it stay in it in carbs.
thanks

 

[Lone Duck]

Re: run the fuel out or leve it in after use

I keep my carbs full. I believe if the carbs are empty when towing, that it is hard on the float needles and seats bouncing around dry. If it is going to be months before you run it again , put fuel fresh in the tank the day you run it. That way, your whole fuel system is protected from corrosion.

 

[robert graham]

Re: run the fuel out or leve it in after use

I use Stabil Marine all the time and a fuel/water separator, drain my carbs a couple of times a year just to be sure there's no water or trash in them. Works like a charm! Good Luck!

 

[TOHATSU GURU]

Re: run the fuel out or leve it in after use

Run it dry and you avoid the possibility of varnish build up due to evaporation and you also don't have to worry about the fuel absorbing water. We have been telling people to run them dry for over 60 years.

 

[Lone Duck]

Re: run the fuel out or leve it in after use

Run it dry and you avoid the possibility of varnish build up due to evaporation and you also don't have to worry about the fuel absorbing water. We have been telling people to run them dry for over 60 years.

You cannot run it completely dry. You would have to drain the bowl and blow the carb out. You cannot do that on the engine. SOOO ! You will still get varnish.

 

[gss036]

Re: run the fuel out or leve it in after use

I am not familiar with Tohatsu engines, but on the Honda, there is a drain port on the bottom of the carb which allows you to completely drain the carb.
I haven't checked my new Yamaha T9.9 to see if it has one or not. I keep fuel in mine because I use the boat year round and I do use Stabil to protect the gas.
I know on my 225 Honda they give instructions to drain the fuel evaporator(?) for long term storage. When I go more than a month I usually pump the primer bulbs to keep fuel in the systems.

 

[TOHATSU GURU]

Re: run the fuel out or leve it in after use

"You cannot run it completely dry. You would have to drain the bowl and blow the carb out. You cannot do that on the engine. SOOO ! You will still get varnish."

Actually they do run completely dry if you use the choke to eek out the last gasp of fuel...However, it doesn't matter if the last 1/4 teaspoon of fuel is left in the bottom of the bowl anyway. The point of running them dry is to get the fuel away from the needle and seat so they don't stick and to get the fuel out of the internal ports. Running them dry accomplishes that.

 

[redfish1940]

Re: run the fuel out or leve it in after use

thanks guys
I called the dealer yesterday after I posted and they say on that carbed motor to disconnect fuel and run the engin till it quits. and start again because it might run for a few seconds.
So they are saying run it dry.

 

[robert graham]

Re: run the fuel out or leve it in after use

No matter what you decide to do on this, remember to use the Stabil Marine all the time(maybe a bit more for extended shut down periods) and you should be in good shape.

 

[Sea Rider]

Re: run the fuel out or leve it in after use

Actually they do run completely dry if you use the choke to eek out the last gasp of fuel...However, it doesn't matter if the last 1/4 teaspoon of fuel is left in the bottom of the bowl anyway. The point of running them dry is to get the fuel away from the needle and seat so they don't stick and to get the fuel out of the internal ports. Running them dry accomplishes that.

I'll second that, to have an empty bowl, remove hose from engine, but when engine it's about to die, play with choke and throttle a number of times, you will have as much as 90% of the remaining gas inside filter consumed too.

Happy Boating

 

[joebob14]

Re: run the fuel out or leve it in after use

All recomendations aside I always run my outbords out of fuel any time I know my boat will sit for more than a weak or two. I had nothing but problems with my carbs ever since they started with the ethenal in the gas. I have not had a single problem since I started running the engine out of gas.

 

[pvanv]

Re: run the fuel out or leve it in after use

For storage purposes, it's most thorough if you use the carb drain screw, to get the last drop out.

 

[JB]

Re: run the fuel out or leve it in after use

What is the oil injection system doing when you run the gas out of the carb(s)?? Does it inject before or after the carb(s)? Seems to me that a carb full of oil would be a worse problem than a carb full of fuel when it dries out.

 

[TOHATSU GURU]

Re: run the fuel out or leve it in after use

Okay, if you have an 05 then the oil pumps into the carb rather than afterward. So that leaves two issues that people like to bring up to justify not running the fuel out.

One group likes to say that running the fuel out can cause a lean condition on one cylinder before the other cylinders run dry.

Not true, but people like to say it.

The second group likes to say that the extra oil from an auto injected system will pool into the carb bowl as the engine uses less fuel.

Also, not true, but people like to say it.

Group one: You are running at an idle and unless your engine was running obviously too lean to begin with, you can't possibly damage it in that two to 5 seconds that the other cylinders continue to have fuel.

Group two:

It is a valid point that there will be extra oil left in the bowl(s). However, that extra two to three drops will almost certainly not contribute to a fouled carburetor. Could it, yes. Likely, no. Experience with 4 brands of auto mixing engines over the last 25 years and I can't think of one case where oil in a bowl occurred where it was noticed, reported and was the cause of anything.


So, why I will personally swear up and down that running an engine out of fuel is beneficial and harmless to an engine, I will also say that there is one chance out of....20,000, 30,000 that you might have a better result by using the drain screw on the bowl. I'm just to lazy to do it