Outboard question

[Louis]

I need your help settling argument I’m having with a friend. I say that you should leave the remaining gas in the outboard when you have docked. He says you should run the engine until the carburetor empties. My reasoning is that the left over gasoline will leave a residue in the carburetor when it evaporates. He claims that this is not so and his engine starts much better his way. I have a two stroke 8hp, he has a 4hp four. What’s your opinion on this?

 

[jimq26]

In the manual for Tohatsu 9.8 they say -

to run the carb dry if you are not going to be running the engine for a week.I never have tried it since we get out a couple of times a week.Two cycle engines are a lot more sensitive to carb gum up.

 

[sailaway78]

Run it dyry

Use stabil in the fuel tank, to help preserve the fuel in the tank. Run the carb dry when you shut it down. The carb jets are very small, and it doesn't take much to plug one up. A carb evaporating dry a couple of times can leave enough gum in there to stop up a jet. The sta bil will help the fuel stay fresh longer, but will not keep it from evaporating.

 

[MoonSailer]

Another Vote for Run it Dry

I have always ran my four stroke and two stroke outboards dry at the end of the day...it the boat is not going to be used the nest day. Figure that the two stroke is 2.5% oil (40:1) so that oil in the carb can't be good after the gasoline evaporates. It is probably good for the environment too as burned gas is less polluting than unburned fuel. I now have a 3.5hp Tohatsu 2 stroke that sits for months at a time without use. I don't add anything to the fuel and it always has started right up..usually on the first pull. I do use the little primer bulb to fill the carb before trying to start the engine.

 

[Benny17441]

Louis read your post again you are arguing for

leaving the gas in the engine while giving the reason that when gas evaporates it leaves a residue. Are you for or against? If the boat is used frequently it does not matter but if you are not going to be using it within a few days go ahead and disconnect the tank or shut fuel valve off and run the engine until it runs dry.

 

[jviss]

Practical considerations

I think there's a lot of folk lore here, and maybe even some potentially damaging information. First, does anyone here with experience with other engines with carbs run them dry after a day's use? Car? Motorcycle? Lawn mower? Weed-whacker? Second, are you aware that running an engine in an overly lean condition, as encounter when running an engine dry, can cause piston and ring overheating, and potential engine damage? The fuel actually provides some cooling effect for combustion chamber components. Finally, how is this done? I assume that engines with internal tanks might have a fuel shut-off, but with external tanks, do you just pull the hose off? I have never been able to do this without spilling a little fuel; with a hot engine, it doesn't seem like a good, safe practice to me. For long term storage, sure, winterize it, including draining the float chamber. For one-week intervals, even multiple week intervals, I have never had gum or varnish form in the float chamber; 'though I've cleaned float bowls of engines that had been left full all winter, of gummy varnish that had clogged the primary jet. After a week, mine starts on the first pull, after a couple of pumps of the priming bulb and two shots of the primer - on hot days I don't hit the primer, and it fires up.

 

[TimCup]

I love you guys!

Being in Florida, I bought a generator for the inevitable hurricane. I assembled it, and it ran great. A few months later, it wouldn't start. I thought the gas went bad (so soon??), so I drained, and refilled with fresh and added stabil. Still wouldn't start. Now I know why!I guess some day I'll read the manuals for this and my outboard, but I was afraid it would violate my membership in the "He-Man-Woman-Haters-Club". Who knows, someday I may even ask for directions!!Again, thanks...cup

 

[jviss]

Exercise your generator

Most standby power generators have exercisers which run the engine weekly, to keep it in running shape. Naturally, gasoline is not a good choice for a permanently installed standby genset, diesel or propane/natural gas is preferred.

 

[Ron]

STABIL does for me

Each fall I run my old 'beater' truck, 4hp Suzuki 4 stroke o/b, Craftsman 18hp lawn tractor, Troy built garden tiller,and weed whacker all with a goodly dose of STABIL in the final mix. Where available I shut off the fuel valve and let the thing run dry. Where no shut off is available, I run hot then switch off ignition.When I return 8 months later, everything fires right up again.Oh, almost forgot 2- 50 cc Honda mopeds likewise.

 

[MoonSailer]

jviss you might be right!!!!

I looked at the owners manual for my Tohatsu 3.5hp outboard two stroke. It does not mention running it dry. It does say for long term storage to drain the carborator and spray it with oil. So you may be right. One old outboard was left with gas in the carb and it dried out and I had to dissasemble the carborator and clean out the jets. It them ran fine. It probably does not matter much either way. What I do is turn off the fuel valve and the engine runs a couple of minutes then dies. This probably does not completely drain the carb bowl anyway. From now on I will just turn off the fuel valve after stopping the engine and see what happens. In my experience most things don't matter very much and a very few are critically important. Unfortunately it is hard to identify and classify things into the proper category. So many old wives tales and misinformation put out by snake oil salesmen that facts are hard to find.

 

[Manny]

After a $100 carb rebuild and being engineless for 2 weeks

I follow my Honda mechanic's advice and run the engine dry. No problems since...Manny

 

[jviss]

RTFM

"After a $100 carb rebuild and being engineless for 2 weeksI follow my Honda mechanic's advice and run the engine dry. No problems since...Manny"The Honda manuals don't say anything about running an engine dry when stopping it. They do, however, (in the case of the the ones I looked at) instruct one to drain the fuel from the carb float chamber prior to storage. I suspect yours sat for a long time - like all winter - with fuel in it, and didn't get the way it did just sitting during the week. I doubt it really needed a carb rebuild, either, if it was only old gas mucking it up. Dropping the float chamber and cleaning it, along with the main jet, plus a little carb cleaner in the other passages to soften anything else would probably have fixed it, in not more than about 30 minutes, total.

 

[Timo42]

Cup, you are banned for just thinking about it

I wouldn't be too worried about overheating the engine, since it will not be under any load, I run my tohatsu 6hp 4stroke with the fuel line unplugged and the cooling system flusher until it runs out of gas. I have a rototiller and a pressure washer that had fuel left in the carb, both are going to have the carbs cleaned out, honda motors, I have an old edger I havent run in years, just added gas and it fired right up briggs and stratton, as I recall it doesn't have a needle and seat, just a pickup tube into the tank. Best to run it dry since there isn't any provision for draining float bowl. Tim

 

[oldiesrocker2001]

I've tried both

I've used both methods with varied success. My 4HP 4 stroke I let run dry at the end of each season in particular and usually the end of each day of use wiht more than a day before expected usage again. While I used fuel stabilizer it wasnt 'stabil' - This cost me a 400. replacement carb. My home generator purchased after the 5-day blackout in my neighborhood(I was assured by neighbors that we were never without power longer than a day)also had similar fuel stabilizer mixed in. A faulty on/off switch required me to shut down using a fuel cutoff after the first few uses. This motor never starts now unless I spray ether at the intake. The same goes for my very large leaf blower that doesn't get run dry. My Lawnmowers and weedwacker and small leaf blower(yes, I DO have more tools than Sears or Roebuck) never get run dry but start every time and ditto for my small 2stroke outboard which only gets drained at the end of it's season-but will sit this season out with the 4stroke working properly for now.

 

[Wayne M]

Run it dry

I have a 1963 Evinrude 9.5hp that my grandfather bought new and always ran the carb dry it runs great and starts on the first pull. I also have a generator for my cabin in Upper Michigan that i run dry after use. I do the same for my snowblowers lawnmower and Harley Davidson and never have any problems.

 

[porsche]

Nissan 6hp

In my nissan 6hp 4str. manuel 2005 modle it states to drain the fuel lines and carb plus fuel pump if the motor is to sit for a long time ??? What is a long time ?? Don't know but if it is going to sit for more than a month I run it dry. But sitting for les than that I never do and have never had a problem. I suppose it would also depend on climate after all we are talking about fuel drying up and leaving a gooy mess right? I live in NC and we hit the mid to upper 90's from now till end of august so there would be more of a chance fro evaperation than say NY right? We could try an experiment and put some gas in a baby food jar cap it with a small hole then sit it out under a bucket and watch it twice a week to see how fast it drys up then I think we would have a good idea how long we can let these sit. I am a mechanic and here I have found that after about 2 months there is gooooo in a sitting small engine. Just a thought Alan

 

[Patrick S/V Shangra-La]

I run my 3.5 tohatsu and my generator dry

never have a problem with each they both start on the first or second pull

 

[Manny]

JVISS I DID RTFM!

You "suspected" wrong.How about knowing the facts before jumping to conclusions?Before storing I did drain the fuel after running it through with sta-bil. The problem started a little over a month or so into the season. It was the first year of the e-10 switch over. I tried replacing the new fuel filter and I installed another new set of plugs. I tried running carb cleaner through the fuel and also spraying some through the air intake. It wasn't gunk in my fuel tank since I had purchased a new, larger tank over the winter.When the Honda dealer I took my outboard to be serviced at came back and said the the carburetor needed to be disassembled and cleaned, I believed them 100%. When I got it back and the Service Manager said the jets were really gummed up, I believed him. When I started the engine after the service it ran as better than ever, I was very happy. The Honda service shop I go to has always treated me like their best customer even though I didn't buy the outboard from them. They have been more than fair on their pricing, have gotten any part I need quickly and without deposit, and have encouraged me to do my own work on the outboard. They've gone so far as to explain procedures to me and show me diagrams of how things go together. The service manager kept apologizing about how long it took for them to get the work done due to the fact that the shop was overwhelmed with engine problems that season due to the fuel issues. I don't have any problems taking things apart and putting them back together, but I don't mess with carburetors. Move one screw 1/20 of a turn out of position and you go from a great running engine to a crappy running engine in a heartbeat. I don't have a problem hiring a pro when something exceeds my comfort level.The shop says run it dry, so thats what I do. Most of the manuals on my gas powered stuff at home state to run the carbs dry, so thats what I do. I know two people that purchased new outboards recently from different manufacturers and they were both told to run them dry.Manny

 

[r.w.landau]

Guys, No Stabile!

The stuff creates a gummy substance that will not go through a carb. The creatures we are says more is better... if you do that with stabile, you are paying for a carb rebuild.Don't use anything over the winter!!!!The question is if the fuel laquers in the carb. The question is if the fuel leaves a laquer on the jet/s if the fuel is left in the carb or if the carb laquers because of lack of fuel. I have done both over the 6 month winter and had no problem. What I have seen is that stabile and other stabilizers are a nightmare to a carb. They create a gooie substance. The carb cannot pass this mass. Don't use it!Sometimes I run my carb dry, sometimes I don't. The motor always runs the same the next spring. Feed it good gas, my old gas is just shaken a bit to mix up the oil in the gas, and it should run like last year. r.w.landau

 

[jviss]

Lighten up!

Manny, no offense intended, honest. What puzzles me, then, is what caused your carb to be gummed up? I confess to having gummed up my outboard carb more than once, from leaving fuel in it all winter. I never used Stabil or any other fuel stabilizer, either, I just used to throw out last year's fuel and buy new; even at $2.00/gallon it wasn't a big deal. To un-gum, I just removed the float bowl and unscrewed the main jet, inspected and cleaned both, usually finding a chunk of gum in the jet, spray the carb passages with some cleaner, and then off I go. I know, its stupid, draining or running dry would be a better idea at the end of the season. In your case, though, I THINK you're saying it wasn't related to running it dry or not, that it was due to the E-10 switchover. Is that so? I can believe it, as the incompatibility of some internal parts with Ethanol, especially carb seals, could "gum up" a carb, stopping the engine dead. I recall a case years ago of Stromberg aviation carbs choking when the alcohol caused float valve seats to swell, starving the engine and causing forced un-powered landings. Not the same thing as "gummed-up" from deteriorating fuel, though. The two are unrelated. Agree?