Gas question

[gaineso]

Hopefully getting ready to go runnin' with my G-stream soon.

1 last big question. I've always, and I mean since I got my first boat in 1950, run the gas out of the carbs. Leave it idling on the trailer til it quits and then pull on out.

Is this good or bad with a carbed engine running 40:1 previously or 32:1 now. Don't want to ding this thing any more than it already is, but don't want crudded up carbs either.

Thanks for any and all replies.

[Stv Euro]

I would think when you run a 2 cycle out of fuel it is not like a 4 cycle. A 2cycle has to have the lube of the fuel and oil. But you know that! I would think it might do damage if not now then later on.

[Techno]

This is just an opinion but I think your doing more harm than good. Your running the engine out of gas/lube everytime you use it.
Carbs don't run out of gas. The bowl level drops and it doesn't supply fuel anymore. There is still gas in a carb when you run it empty.
You want to find out for yourself take one off sometime.
Crud don't grow in the fuel if your using the boat. It's when it sits for extended times. Then there is that stabil stuff to add to your gas.
The best preventive measure though is to use the boat every week/weekend. Use most of the fuel supply and scrape up enough $$$ for another tankfull next week.

[gaineso]

Answered my question. I won't run it out any more. I always use Quicksilver stabilizer in it anyway, so should be okay. Just sometimes don't have time for usingt it every week. I can always buy gas. That's what the plastic money's for. Don't have to pay for it. Thanks for the opinions.

[Hooty]

The big problem is the premix evaporating in the carbs and leaving a big bunch of caca. What I do if, the boat isn't in use for a week or so, is give the bulb a couple of squeezes and keep the carbs full of fuel. Works for me.

c/6

Hooty

[Hydroballistic]

Hooty has the second best idea, 1st being to use it every week. But if you forget to pump that primer bulb you will get the "caca", as Hooty called it, in your carbs eventually. I always tell my customers to #1 use stabil, #2 leave gas in carbs IF you can remember to come by every couple of weeks and pump up the primer bulb, or #3 run the gas out if you can't remember (I can't).

my $.02

[QUICKSILVER]

This is not the answer to the questoin that you asked, but it might be something to think about. I don't think your origonal problem was oil related. It was octane, ing. timing, fuel starvation or over heating. When you add more oil you lower the octane rating of the fuel. You are going to 32:1, why?

[Forkin' Crazy]

I axed this question once before......:o

I always run my gas out. I was advised not to by members of this board also. I continue to do so.

A lot of the oil stays in the engine. There are oil ports for it to get to the bearings. When I pulled down my 235 for it's first overhaul, it had oil on the crank and everything. Even on the rings and cylinders. I still run the gas out. Even if it is only a week until I run it again. I had a magnet come loose on my flywheel last year. I pulled the heads looking for the noise and expecting the worst. After at least 75 hours of use it still had the cross hatch in the cylinders.

I have a '79 model 100 hp Johnson. Always have run it out. It was on a bass boat at one time. My buddy took it to run the lines. He did not know I did not put any oil in the gas!!!!!!!! Had to go 4 or 5 miles round trip. Siezed on the way back. It was down stream so they drifted a while. Fired it up and idled into the cove. He told me what happened. I squirted some oil in the carbs and in the cylinders, added oil to the gas and it ran perfect. I now have it on my Starcraft which sees several hours a year and still runs 48 mph on the gps. Other than the carbs and water pump I have never done anything to it. I still run the gas out of it.

Plus you don't have gas seeping out all over everything.

So, should you? I have an inline too. If a Merc can hold up to it...LOL! We'll see!;)

[Forkin' Crazy]

No one else has an opinion?:rolleyes:

Boy can I kill a thread...............:cool:

Think I'll go ride in my boat and blow away a few Mercs...LOL!:eek:

[Raceman]

When I got my first inline Merc in the 70's I was at the lake with a friend who's dad had worked with Merc for years, running the proving grounds at Sarasota for part of that time and also having a stint at Lake X. He saw me disconnecting the fuel line to run the gas out and said it was the worst thing I could ever do for exactly the same reasons above. It might be almost worth running the lube out fo the engine if the trade off was gettin' the carbs dry. Problem is, just like Techno already said, you don't get it all, but leave a smaller amount to evaporate quicker and sludge the carbs. The best advice was already given.......... pump the bulb or hit the electric pump frequently.

As far as the argument for extra oil hurting the octane rating a significant amount, I've heard it before too. While I guess it's true to some degree, I think the benefits greatly outweigh the downside. All of the older race motors, including the early V6's had a recommended mix of 18:1 and octane wasn't an issue, even though many people ran em on pump premium.

I ran everything I own at 25:1 for years until the oil got better and the only powerhead I ever lost had somebody else's mix in it as well as their timing setup. I've got motors that I've had for decades and when I looked in em you can still see cross hatch in the cyls. Even with synthetics, I never run the oil leaner than 32:1.

[Forkin' Crazy]

Originally posted by Raceman

As far as the argument for extra oil hurting the octane rating a significant amount, I've heard it before too. While I guess it's true to some degree, I think the benefits greatly outweigh the downside. All of the older race motors, including the early V6's had a recommended mix of 18:1 and octane wasn't an issue, even though many people ran em on pump premium.


As long as it is jetted accordingly.:D More oil does lean the fuel/air mixture.

I guess the OMC's are just tougher than the Mercs...:eek:

LOL!

[Mark75H]

Think about this: oil is fuel, too. Extra oil does not reduce the amount of hydrocarbon going into the motor, so you can not be changing the mixture enough to change a jet requirement. Its an urban myth.

[Jay Smith]

Thats one of the quickest way I know to make a motor builder rich. The bores being dry after this process has been done and the lag time it takes for the fuel vapor to reach the bores to lubricate at the time of the next outing is very abrasive to the bores and the premature wear would be 10 fold. I ask people
( mostly old timers at the ramp ) why do you do that , and there answer " is to run the gas out of the carberator Boy " and THAT is HORSE HOCKEY Forkin' Crazy when a carb is "RUN OUTTA GAS" @ idle it has depleted nothing out of the bowl but the upper idle jet area the bowl is STILL FULL of fuel if you don't believe me the next time your at the ramp let your motor idle till it dies and then remove the bottom bowl plug and see what is left in the bowl , have a rag ready to catch the gas cause your gonna need it...... To run the main circuit jet out and loose the bowl level to do some good one would have to run with a high enough RPM to transistion to thatmain jet circuitwhich is in the upper RPM range!

I would rather a customer CHOKE one till it died oiling the bores THEN remove the bowl plugs in the bottom of the bowl if thats your intention , thats the ONLY way to get the gas from the entire bowl .

Just my opinion,

Jay

[Forkin' Crazy]

Originally posted by Mark75H
Think about this: oil is fuel, too. Extra oil does not reduce the amount of hydrocarbon going into the motor, so you can not be changing the mixture enough to change a jet requirement. Its an urban myth.

Mark, I see what you are saying. But going from 50:1 to 25:1 you would not have to rejet?

Jay, I have an opinion just like you. I am gonna try what you said. If you are right, I will concede. I am hard headed and a dumb ass to boot.....;)

BTW if that is one of the quickest ways to make a motor builder rich, then I would be broke as hell. Not that I have a lot of money anyway....:rolleyes:

Thanks, have a nice day!:)

[rob vaughn]

We've been doing it since 86, and had no problem....

The trick is keep your idle down and as soon as you hear the motor going lean, shut it off....

At 32:1 the cylinders will have plenty of oil.... The 2.4 of my father's was tore down( only tear down on an 86 motor) and there was all kinds of oil in the cylinders....

What running them out does is keeps your carbs. clean,preventing the oil and fuel from gumming the carbs. up!!!!

Just my two cents worth!!!!!

[VectorPat]

I do just as many carb jobs on motors that have had the gas run out of them(according to the customer) as ones that dont..And it doesnt matter if its premix or injected either..Oil doesnt gum up a carb(unless its crap) as much as gas alone does..As far as stabilizers go if your get as much heat and humidity as we do down here it doesnt seem to help much..Keep your fuel in a cool dry place away from sunlight..Boats that sit out in the weather will have carb problems much sooner than one kept in a garage..Never seen carbs gummed up because the boat gets used too much;)

[Techno]

If this is such a good idea for carbs then this should be great for EFIs.
Injectors have tiny orifaces and screens so need this anti-gumming procedure too. Shut the fuel pump off and let the engine die. Then again there is all that stuff lubing the engine that may potentialy gum up, so run it out on alcohol to clean the engine out too.

Instead of does it do any damage how about does it do any good? What good does this procedure do? There are alot out there that shut the engine off when they reach the dock and yank the boat out. They don't have oiling problems or gunk in their carbs. All the same things can be claimed by them.

If it's too difficult to pull a bowl, then run the engine normally for a season and see if it's all gunked up. It ain't like we're talking major overhaul here. Otherwise it's a fine procedure for making you feel like your accomplishing something usefull.

[Raceman]

"What running them out does is keeps your carbs. clean,preventing the oil and fuel from gumming the carbs. up!!!! "

Rob, that's the specific part of the running the fuel out argument that I disagree with. There's no way that running them out keeps em clean and prevents gumming, because it doesn't run them completely out unless you're gonna pull the plugs in the bottom of the bowls which many carbs have. It only lowers the level, promoting faster evaporation. There's always a puddle in the bottom of the bowls. If anything, running the level down this low promotes gumming.

The only reasons that the running the gas out habit got started in the first place was that the early little kickers frequently got removed from the boat and put in the trunk for the trip home. Also, the smaller boats were frequently towed with the motor tilted up and this dripped gas over into the back of the boat. Burning the gas in the bowls down to whatever level it would burn to was desireable in both cases as an anti-drip measure. I originally used to run the gas out of mine, just because my dad always did it to his and I thought it was the right thing to do. The guys at Merc convinced me it was a bad idea and I haven't done it since.

[Mark75H]

50:1 vs 25:1 is 2% and 4%; and as I pointed out earlier, still fuel.

Do you really think you can make a less than 2% estimation of mixture strength? I know I can't.

[rob vaughn]

Sounds good here.... As I have said in other posts, " what works for one, might not work for the other"...

We run two Mercs, an 86 & a 93 model, and one does get tilted up and mine does not, but I will continue to run it until it starts to lean out and then turn the key off..... Maybe it is not required but I will argue all day, that it hurts a motor!!!!

I would not advise reving it up, but at idle .....

Not trying to start anything here, but just saying what I do!!!!!

[Forkin' Crazy]

Hi Sam....sorry about calling you Mark....was looking at you screen name.

Several years ago, this guy had a 2 stroke dirt bike. He kept on smoking pistons. He kept on adding more oil. My friend and I told him he needed to jet up. He would not listen and kept addin more oil and burning up pistons...This is where I was basing my threory. Thanks for answering my question.

Even if running it out of fuel at the ramp does not remove all the fuel from the bowls, it would remove some of the "caca" that would be left over from a full bowl...seems like it anyway.

Hooking the boat up right now. Going to pump her up and check the volume, and when I take it out, check it again.

:D

[Raceman]

Paul, where you get in trouble with crap in the fuel bowl is when the gas evaporates and leaves the oily residue in the bottom. The theory is, 10 times the volume, 10 times the timespan for the evaporation to occur. Of course if the motors gonna sit there long enough for it all to evaporate either way, then obviously the less residue the better.

[Mark75H]

Sounds like the guy with the dirt bike just needed to go with bigger jets, I don't see any conflict.

[gaineso]

What I was wanting when I started this thread was a good solid definitive, unarguable yes or no.

Seems I've gotten a really solid MAYBE, slanting towards don't run it out.

Guess I'm just gonna be forced to use the boat more often and then not worry about it.

Now I'm sure you guys understand my reluctance to be forced to use the boat more often. Definitely not what I needed.

:D :D :D :D

[Forkin' Crazy]

Originally posted by gaineso
What I was wanting when I started this thread was a good solid definitive, unarguable yes or no.

Seems I've gotten a really solid MAYBE, slanting towards don't run it out.

Guess I'm just gonna be forced to use the boat more often and then not worry about it.

Now I'm sure you guys understand my reluctance to be forced to use the boat more often. Definitely not what I needed.

:D :D :D :D

Gaineso, every one has an opinion. I respect others opinion, but only if they respect mine.

You don't need to use the boat more often??? LOL!

[Forkin' Crazy]

Originally posted by Jay Smith
THAT is HORSE HOCKEY Forkin' Crazy when a carb is "RUN OUTTA GAS" @ idle it has depleted nothing out of the bowl but the upper idle jet area the bowl is STILL FULL of fuel if you don't believe me the next time your at the ramp let your motor idle till it dies and then remove the bottom bowl plug and see what is left in the bowl , have a rag ready to catch the gas cause your gonna need it...... To run the main circuit jet out and loose the bowl level to do some good one would have to run with a high enough RPM to transistion to thatmain jet circuitwhich is in the upper RPM range!



Just my opinion,

Jay

The results are in.

Before I went to the river I pumped my fuel bulb until is was hard. I then bled any excess pressure at the mechanical pumps. I drained the fuel into a graduated cup (not a rag). Full, it was about 35 cc. I played all afternoon racing around the river (oh much fun!:D). I ran the motor until it quit. Pulled it up the ramp and pulled the plug and used the graduaded cup. Only a very small amount of fuel came out. I could not even measure it. I am thinking about going back and using a graduated cylinder to be more accurate.

Jay, you must be use to Merc carbs, because on an old OMC Crossflow, the emulsion tubes go almost all the way to the bottom of the bowl.

Like I said, I am hardheaded. If I don't quite believe some one, I will try it myself. Note: this does not apply to jumping off of a cliff or something like that!

:)

[Forkin' Crazy]

Originally posted by Jay Smith
Thats one of the quickest way I know to make a motor builder rich. The bores being dry after this process has been done and the lag time it takes for the fuel vapor to reach the bores to lubricate at the time of the next outing is very abrasive to the bores and the premature wear would be 10 fold.


If that were true, Jay, my boat would have at least 750 hours on it. I doubt that the cross hatch would be visable.

I hate to bring this up, but you sounded as if you were belittling me. After all, I am just a farm boy, not a "race engine builder".

If I were wrong, I would appologize, but I am not (the bowl thing). I see you have made no reply.

Sorry, I just could not let this go....:(

[76baja18ft]

well i know for a fact when i run my crossflow (1976 200 johnson) dry.. u can pull the plugs on the bottom of the carbs and all you will get is just a small dribble.....never more than a few drops...

[BLUElixir]

What about all the jet-skis that run out of gas between "on" and "reserve"? I'm sure that this must happen alot and if it did damage I would think that the manufacturers would quit putting a fuel switch on the PWC. I do realize that the PWC usually would be restarted immediately after running out of gas (and switching to reserve). So a minimal amount of cranking would be needed to start it up again and there would probably be lots of oil in the cylinders. Its not the same as running it out at the ramp but just something to think about. I'm definitely not an expert.

Personally I try not to run anything out of gas.

[JTS Racing]

Most of the jetski/wetbikes are oil injected. They get oil from just cranking.

[BLUElixir]

Thanks for pointing that out Hydro. Most are oil injected now but there are still a couple, and there have been many in the past, that were not. Just food for thought.

[Ron V]

Guys, this whole thing is really not that big of a deal. As far as it damaging the motor, I've never seen that materialize. There is actually enough residual oil in there to run a motor for quite awhile; hasn't anyone ever heard of these tests where they run the motors on straight gas and they run for quite a long time? So how can a momentary sputter cause enough starvation of lube to damage the motor?

Do you guys with these gas guzzling 2.5s mean to tell me you have NEVER run out of gas while tearing down the lake? I have, many times, with many motors--often at full throttle. Yet, somehow my motors suffer no ill consequences.

In the older Mercury manuals it said to run them dry at the end of the season. Find one and read it. In fact the ONLY way to store a motor long term is to get the carburetor good and dry, either by running it dry or disassembling it and drying it out if necessary.

As for whether it does any good, that depends on the motor. SOME carburetors WILL RUN DRY. Others will not. On the ones that won't, you are better off to leave them full for storage because then hopefully only part of it will evaporate instead of leaving some residue.

All of the hype that is all over the Internet and launch ramps about gummy carbs mostly involves people who are ****ting in their gas tanks and then letting the motor sit for five years. I've never seen a carburetor gum up in one winter, with or without Stabil.

[Mark75H]

I've never seen a carburetor gum up in one winter, with or without Stabil.

I have.

[Carbinite]

I can't believe the three pages so far on this subject but here I go adding to it. Just shut it off. If there is only a small amount of premix in the bowls it will evaporate and leave sludge. I haven't shut my petcock on my lawnboy or weekwacker in 10 years. Never a problem.

[Raceman]

"If there is only a small amount of premix in the bowls it will evaporate and leave sludge."

I think that's been said about 10 times in this thread now.