Do you run the gas out of your two stroke engine after each use?

[Fronterra]

What are the implications if you do or don't?

 

[Georgesalmon]

Re: Do you run the gas out of your two stroke engine after each use?

Many thoughts from many people. Mine is that I don't. I think that when running out the gas at the end you get a very lean mix for a couple of seconds than can't be good for the engine.

 

[Sea Rider]

Re: Do you run the gas out of your two stroke engine after each use?

Is it a 2 or 4 strokes engine ? No issue with 4 strokes. If it's a pre mix 2 stroke will have issues, will depend on you boating outings. If very frequent all year round, no issues. If no boating for 15 or more days, burn all mixed fuel. Fuel evaporates with time and leaves oil residue on carb that could stick float along narrowing thin fuel passages making engine not to perform as expected. A must do for winterizing, along bowl screw removal to drain last drop out.

Happy Boating

 

[JB]

Re: Do you run the gas out of your two stroke engine after each use?

I always did with my premix 2 strokes. I now think that was at least partly a mistake, though I never had any trouble from it.

The mistake was with multi-carb engines. My theory is that one carb will go dry before the other(s) and risk damage to bearings and cylinder walls. As I said, I never had a problem but I wouldn't do that any more.

Now with oil injected, carbed 2 strokes I never did. That would be a bad idea to burn off the gas and pump the carb full of oil.

I see no benefit to burning off fuel in four strokes and DFI 2 strokes.

 

[Fronterra]

Re: Do you run the gas out of your two stroke engine after each use?

The reason I ask is because I have owned 2 different 2 stroke engines in the past 2 months and both have given me issues after about 4 or 5 uses. I was wondering if because I ran the fuel out after each use could that be the issue I am having (hard starts, running rough, fully choked,etc)

 

[Home Cookin']

Re: Do you run the gas out of your two stroke engine after each use?

more likely your problems are caused by ethanol poisoning: gummed carbs, stuff in the lines, fuel gone bad in the tank. First try some fresh fuel, and sea foam, and take a look at your fuel line from tank to carb.

Like others I used to run them out; don't any more. used to have a Yam that if you didn;t run it out and it sat more than 2 months you had to go to the shop. I think it's one of those things that used to work or matter and doesn't any more, although ethanol poisoning is a new problem to deal with. Also having read many detailed and informed opinions, it seems that if you could run it all out, fine, but since you always laeve some behind, it's worse.

 

[fishrdan]

Re: Do you run the gas out of your two stroke engine after each use?

I have owned 2 different 2 stroke engines in the past 2 months and both have given me issues after about 4 or 5 uses.

"What" outboards are those, brand, HP?

I've always run my outboards dry (at idle) and have never had an issue, but I've only owned single carb premix 2 strokes. Small outboards in the 5-15HP range.

 

[Fronterra]

Re: Do you run the gas out of your two stroke engine after each use?

"What" outboards are those, brand, HP?

I've always run my outboards dry (at idle) and have never had an issue, but I've only owned single carb premix 2 strokes. Small outboards in the 5-15HP range.

1989 Mercury 25, 1986 Evinrude 9.9

 

[Sea Rider]

Re: Do you run the gas out of your two stroke engine after each use?

If runing carb dry, take advantage to flush engine while sitting on stand or transom, this gives a 5 minutes flush at fast idle. For next outing just prime bulb again untill firm and start engine as usual. No experience with multicarbed engines as have been doing this for lots of years on single carbed 2.5 to 40 HP pre mixed engines with excellent results.

Your sympthoms could be related to fuel, mechanical or electrical issues or as simple as bad head gaskets failures due to age, both engines are oldies, dried out, hardened gaskets, compression issues, or letting small water droplets pass into combustion chambers causing poor performace specially at 3/4 to wot.

Happy Boating

 

[robert graham]

Re: Do you run the gas out of your two stroke engine after each use?

I always drain each carb with the float chamber drain plug several times a year and especially for motor lay-ups of several weeks or months. Naturally water, debris, fuel residues, etc. will accumulate in the float chambers and draining is very good preventive maintenance. "Running fuel out of carbs" ain't the same as draining. Of course, on my 90C Yamaha draining each carb is an easy 5 minute job...maybe more trouble on other motors?....

 

[foodfisher]

Re: Do you run the gas out of your two stroke engine after each use?

Single carb. OK. Multiple carbs. no way.

 

[ondarvr]

Re: Do you run the gas out of your two stroke engine after each use?

It's been probably 6 or 7 years since I ran a motor dry, and then it was only on that one occasion, it doesn't do much to help, there is still fuel in the carb unless you drain it out of the bowl.

Mine sit for months on end and I rarely (if every) have an issues starting them, and I'm a 20+ year ethanol user. This doesn't mean your carbs are clean, only that running them dry or not most likely has nothing to do with it.

 

[Texasmark]

Re: Do you run the gas out of your two stroke engine after each use?

Before the days of injection I always did but for the most part I only had one carb. On here some of the mechanic guys mentioned the fact that one carb will run out before the others on multi carb engines but I feel that there would be enough residual oil to keep things lubed in that short period till all quit. I agree with JB on not doing it with injection and on my current engine, first one with injection, I didn't.

For what it's worth I ran my current engine for 7 years (oil injected) never running the fuel out. Sometimes it would sit for 6 months idle in the off season. Ethanol has been in the gas pumps here for several years and you have no choice but to run it. Recently I pulled my carbs to do their first cleaning and there was not one single bit of gum nor varnish in any of the 3 bowls. They were spotless but I did find foreign material in the fast circuit of one and slow circuit of another but I attribute that to my decomposing fuel line. Buttttttt here's the caveat: I use Sea Foam religiously!!!!! Speaks for itself. I am hooked on additives because they have proven their worth to me; no brag just fact!

On additives, I am noticing that after market fuel additives are not only made available by OEM OB mfgrs. as stand alone products, but also in things like 2 cycle engine oil for chain saws and other equipments that have long idle time periods. Must work for them too!

Sea Foam has been around for over 50 years. I subscribe to the theory that quality survives the test of time so this one apparently does what it advertises. Do I work for the company? No. Actually I didn't hear about it before I got on this site back in '04.

Mark

 

[wn6ngp]

Re: Do you run the gas out of your two stroke engine after each use?

I am a new convert to Sea Foam.
due to the drought in Central Texas our boating opptys have diminished. Mine was not run for most of last year. So when it came time to use it I had a bad time. I did not want to get into a tedius job of tearing down 3 carbs(the right thing) so I ran some straight Sea Foam into the fuel line several times and it finally cleared things up. Once I got it started I ran it on the lake and I could feel it as the power ports of each of the carbs cleared. The last time out to test it I ended up towing a skii boat home.

My neighbor did not use his boat for 3 years. He had put Sea Foam in it last time he used it. He says it just started right up.

So I don't know whats magic about Sea Foam but I always keep a can in the boat now. They claim you can use it directly with no harm, unlike other carb/injection cleaners.

don

 

[Texasmark]

Re: Do you run the gas out of your two stroke engine after each use?

I am a new convert to Sea Foam.
due to the drought in Central Texas our boating opptys have diminished. Mine was not run for most of last year. So when it came time to use it I had a bad time. I did not want to get into a tedius job of tearing down 3 carbs(the right thing) so I ran some straight Sea Foam into the fuel line several times and it finally cleared things up. Once I got it started I ran it on the lake and I could feel it as the power ports of each of the carbs cleared. The last time out to test it I ended up towing a skii boat home.

My neighbor did not use his boat for 3 years. He had put Sea Foam in it last time he used it. He says it just started right up.

So I don't know whats magic about Sea Foam but I always keep a can in the boat now. They claim you can use it directly with no harm, unlike other carb/injection cleaners.

don

The MSDS (Material Safety Data Sheet) is online and the product is composed of mineral oil, alcohol, and naptha. Mineral oil is just straight oil, alcohol could be wood or grain, naptha could be any of a dozen different concoctions. Some folks choose to mix their own. I just buy it in the proven product form, in the OEM can.

The story I picked up on states that 50 years ago OMC was looking for something to improve performance. Maybe had to do with colder climates and combustion by-products causing engine problems. I do know that the oil is deliberately put in there so you can use it for a starting fluid in 2 cycle outboards requiring oil that you don't get in regular engine starting fluid like would be used on a 4 cycle engine....or didn't used to....some advertise an added lubricant now-a-days but don't say what, nor how much.

Mark

 

[Fl_Richard]

Re: Do you run the gas out of your two stroke engine after each use?

IF I only had one cylinder I would. But with V6's running dry... there is no way.

Maybe the new Etechs with oil injection would be ok? The might continue to squirt oil after the gas is gone.....

 

[pnwboat]

Re: Do you run the gas out of your two stroke engine after each use?

I have two carbs on my outboard motor and I use full synthetic 2-stoke pre-mix and have never drained the carburetors or ran them dry for storage over the winter. I've not seen any evidence of gummy oily build up. Fires right up every time when spring time comes.

 

[pecheux]

Re: Do you run the gas out of your two stroke engine after each use?

Ran a Merc 115 hp Tower (6 cyl) for 5 years without ever running dry, even for winter storage. Never had any issues. Same with presently owned 9.9 and 15 hp, but now I always have 1/4 portion of stabil + carb cleaner in the tanks for precaution since I dont used them very often.
Cheers

 

[wn6ngp]

Re: Do you run the gas out of your two stroke engine after each use?

Hey Tex, when you say , . I just buy it in the proven product form, in the OEM can., what are you referring to? Naptha?

I can live w/o adding yet more alcohol if thats whats in Sea Foam.

Lowes sells naptha by the gallon.

Tex in Centex

 

[64osby]

Re: Do you run the gas out of your two stroke engine after each use?

14 years of boating with 2 different main motors, 6 kickers, all 2 strokes, have never run them dry, nor drained the carb on any of them.

Never had an issue come spring time.