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An old mechbs advice good or bad

Q

qlty

Member
"I was told a few years back t

"I was told a few years back to disconnect the fuel line and let the out board run out of fuel to keep the fuel in side of engine from asorbing moisture and causing corrosion,this was after ethinol was added to our gas here in New York.Wondering if this might put a strain on a vacume type fuel pump?Any one have a comment on this practice??"
 
"It is absolutely the best thi

"It is absolutely the best thing you can do ----WHEN YOU TAKE THE BOAT OUT OF THE WATER, RUN THE FUEL OUT----some people will say that it is bad , but there are too many " old wives tales " ---from 40 years experience."
 
"(Running Engine Out Of Ga

"(Running Engine Out Of Gas)
(J. Reeves)

If the engine has but one carburetor, it's unlikely that running the engine out of gas would do any harm. When the carburetor runs out of the fuel/oil mixture, the engine stops running.

However, a engine that has more than one carbuetor should simply be shut off. The reasoning is that the top carburetor will run out of fuel first due to gravity and the engine will continue to run on because of the still existing fuel in the other lower carburetors.

This results in having at least one aluminum piston running up and down a steel cylinder wall with improper or no lubrication. Not a good idea!
OR simply clisk on the following hyperlink

When time permits, visit my store (copy/paste) at: stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"Sorry, oil that is on the bea

"Sorry, oil that is on the bearings /between the piston and cylinder does not know that " the motor is running out of fuel,I have to get out of here this very instant ". this is the way it is ---there is lots of oil in a 2 stroke that has been in the engine for a minute or so, it just DOES NOT DISAPPEAR IN AN INSTANT."
 
"John.... Think about it. When

"John.... Think about it. When that top piston starts to score, let us know about it."
 
I have never seen it in an own

I have never seen it in an owners manual or factory service manual " caution do not run fuel tank empty as motor damage will occur" ---It is OK to run an engine out of fuel and it is the best thing to do to keep carburetors clean.Sure beats damaging an engine from lean condition due to partially blocked jets.
 
"I would like to put in my two

"I would like to put in my two cents...It would seem that at idle speed, as soon as any of the carburetors runs out of fuel, the motor would stall...at higher speeds the motor would of course continue to run but at idle speed(depending on how many cylinders the carburetor is supplying) it seems that the motor would shut down when the carb runs dry...as I said, thats my two cents...It may not even be worth that!"
 
To further add to this ---How

To further add to this ---How could good old OMC promote something called VRO for years. A motor idling for a prolonged perion would have less oil in the cylinders and bearings along with a lean mixture in the carburetors!!!----I have never seen a warning " DO NOT CRACK THE THROTTLE OPEN SINCE THE MOTOR WILL BE DAMAGED "
 
"this is getting good!
anybod

"this is getting good!
anybody rem what the service manual says,for off season storage?"
 
"First of all, I'd agree w

"First of all, I'd agree with just about anything Joe says (read his signature - 30+ years with OMC). It makes perfect sense. If one carburetor has enough fuel in it to keep the engine running on 2 cylinders on a 4 cylinder engine (like my old Merc) for several seconds after the other one has ran out, it could mean bad news. The last mixture in the cylinders would have been extremely lean anyways. Now the pistons are being asked to move up and down with little to no lubricant.

Yes, there is some residual lubricant in the cylinder, but depending on how long the engine stays running there may not be enough.


Anyways, with my old small outboards (that only have one carb), I always pull the fuel connector when nearing shore and allow them to run out of gas. Otherwise it generally just pours out the connector when I disconnect the gas tank anyways.
On my 2-line pressure tank motors I loosen the cap to relieve the pressure first of course."
 
"This is sounding like the tv

"This is sounding like the tv show "Mythbusters" I'll add another 2 cents...The Merc/Yamaha 4 cylinder from the 90's was a 2+2 arrangement that ran on the upper two cylinders until about 1800 RPM when the bottom two cylinders kicked in. The motor was oil injected and at idle the fuel/oil ratio was said to be about 150 to 1. Under 1800 RPM, the bottom two cylinders received only enough fuel to lubricate the cylinders but not enough to fire the cylinders. The idle circuit was fixed on the bottom two carburetors and would only let in extremely small doses of the 150 to 1 fuel mixture. The motor could run forever at idle speed despite the fact that the bottom cylinders were only receiving very minimal oil. It seems that at idle speed the oiling demands are not excessive. I had a lawnboy 2 cycle mower for over 15 years and I never added gas until it ran out...Almost always at full speed. It ran out this way several hundred times and was still running well when I got rid of it."
 
"This is sounding like the tv

"This is sounding like the tv show "Mythbusters" I'll add another 2 cents...The Merc/Yamaha 4 cylinder from the 90's was a 2+2 arrangement that ran on the upper two cylinders until about 1800 RPM when the bottom two cylinders kicked in. The motor was oil injected and at idle the fuel/oil ratio was said to be about 150 to 1. Under 1800 RPM, the bottom two cylinders received only enough fuel to lubricate the cylinders but not enough to fire the cylinders. The idle circuit was fixed on the bottom two carburetors and would only let in extremely small doses of the 150 to 1 fuel mixture. The motor could run forever at idle speed despite the fact that the bottom cylinders were only receiving very minimal oil. It seems that at idle speed the oiling demands are not excessive. I had a lawnboy 2 cycle mower for over 15 years and I never added gas until it ran out...Almost always at full speed. It ran out this way several hundred times and was still running well when I got rid of it."
 
In order for oil to " lubr

In order for oil to " lubricate in an outboard " it has to condense out of the mix and coat the parts as oil.Now oil does not instantly disappear off the cylinder / piston / bearings because one carburetor has run out of fuel. Years ago friends had a 66- 100 hp Johnson with 3 6 gallon tanks.We used to ski and fish all weekend ( it rarely cooled down ) and we always ran the tanks dry ----NEVER EVER A LUBRICATION PROBLEM !!!!
 
"My comment on this from what

"My comment on this from what I've read is if you use nonoxygenated fuel, which I do and you should is, there is no need to run the motor out of fuel.If this fuel is not available to you then when using the ethynol fuel you NEED to install the inline fuel canister filter (big one) If your boat is used at least every 2 weeks, again there is probally no need to run the fuel out. Brian"
 
"My "old mechanic" tol

"My "old mechanic" told me essentually the same as John's question except he said to choke the engine to kill once it starts to rev up. The idea was to get the float valves off their seats, minimize gum in the bowls and throw a rich mixture of oil in the cylinders. I have been doing this for 20 years now in '75, 115 and have never had a carb or power head problem.
However, I have not considered Joe's senerio. I have some soul searching to do. Hopefully, the "rev up" happens before the top carb runs out or just as it does."
 
"I have never liked the 'r

"I have never liked the 'run empty' way of two-strokes.
All VRO engines have the oil-pump mechanically linked to the fuel pump. Unlike the smaller pumps, the VRO does not pulse with the over/under pressure of the crank case, but gets activated, at idle, one stroke about every 15-20 seconds, providing there is pressure between pump and carb. Take away that pressure and the pump goes berserk, not pumping fuel, but pure oil! You end up with pump and carbs filled with oil instead.
You may dry-run a 2-stroke, tear it apart and there will still be a lot of oil around, but!
Look at the piston skirts in a microscope and notice the grooves. These groves are there to keep the oil and lubrication between pistons and cylinder walls.Same goes for hone-scratches in the cylinder walls. Take away the grooves and scratches and there is nothing to hold the oil, take away the oil-supply and these groves and scratches will soon be gone and the result is 'polished' piston skirts and cylinders, first stage of a melt down. Each time an engine is run 'dry' and the lubrication here is taken away, the wear multiplies compared to normal operation.
If You do not want to store the engine with empty carbs, drain them, but don't run it dry!"
 
"Oil coats all the internal pa

"Oil coats all the internal parts of the motor, an oil mist does not lubricate.Oil is still all over the parts when carburetors are run empty."
 
"ikia:
You have to split betw

"ikia:
You have to split between 'oil-coat' externally for corrosion protection, and rebuild of oil-film for lubrication.
The first part is no problem if running the engine 'dry', but the second part is!
Most of us 'old' OMC mechs knows what happened when they reduced oil mix to 100:1.
Reducing it to 0 does not make it better!
It has a lot to do with alloys used in the different engine components, and unfortunately the OMC's need that oil. Yamaha's seems a bit better, I run my 40 Enduro on 100:1. The new E-techs have a 5 hr 'warranty' of getting home without oil, but I do not think I would try!
The 'problem' area is not bearings, but piston skirts/cylinder walls that need a constant 'flow' of oil-mist to keep friction down between piston and cylinder."
 
"as interestting as this has g

"as interestting as this has gotten-----I have the right to remain silent,..I just dont have the ability!!(thats a joke Morty)!

I grabbed a service manual,from the 80-'s off the shelf,and looked in the 'off season storage'
--It just reccomends treating the fuel basically,as for as the carbs are concerned..
I have had prob hundreds of customers,over 31 yrs,that have run the fuel out..w/seemingly little probs due to that..
I have also seen hundreds of scored/damaged eng's..
Nowadays,...most of the engs we see,are still on VRO/OMS---..
You never run an oil injected eng,out of gas,...so treating/draing would be considered the solution.on a multi carbed eng,i could see the potential probs,as the higher carbs run out of fuel,lowers continue for awhile.Everyone above,makes some excellent points.As well as we could educate,the boating public,it is always up to the boat owners decision,and what his buddies do_On a single carbed,SMALL eng,..I dont think anything major could occur,since u r running on the 1 carb.
What we do,and i recommend,at my shop,..is treating,.AND DRAING,of the carbs for off season storage,OR ,treating/stabilizing the fuel,and running once a month for 15 min."
 
"[b]I have the right to remain

"I have the right to remain silent,..I just dont have the ability!!
That makes 2 of us, and is what keeps the board running!
happy.gif
"
 
I think we have beat this subj

I think we have beat this subject to death...how about the one about ruining your boat battery by storing it on a concrete floor??? Does anyone believe this???
 
"Well Bob, now that you mentio

"Well Bob, now that you mention it......

Many years ago, I'm going back into the 1950's here, one of the businesses my father owned was a used car and salvage yard business. This of course involved removing many batteries from wrecked vehicles, then storing them for resale.

Back in those days, and I would assume that the practice still exists, many of us would grab the sides of the battery and hook out thumbs over the battry terminal posts to lift and move them. Although stored inside, during damp weather, occasionally grabbing those terminals would result in quite a shock.

Some would say.... a shock, from 12 volts? Yes, it's true, nobody related this to me, I know it for a fact.

Now, the description of a "fact", that's another story that I can write about later if anyone's interested.

Getting back to this shock thing, we found that having the batteries raised off the floor, setting on a piece of wood, 2x6, 2x8, something like that, caused the shock to cease. It appeared that the dampness and the cement floor did have some effect on the batteries. The elimination of the shock I would assume would depend on whether one was barefoot or not. I didn't test this theory.

Whether the piece of wood had any effect on securing the quality of the batteries is an unknown but it did raise the comfort level of moving them around.

How about those flying saucers back then? Wow!"
 
"Hey Joe...I'll bet some o

"Hey Joe...I'll bet some of those batteries were 6 volt...They were also the tar top variety and pennies were stuck into the tar to reduce corrosion...You said you hooked your thumbs around the lead posts...Today, any lead exposure (including handling fishing sinkers) is enough to scare most parents. You can even get a mild shock from a 9 volt dry cell if your fingers are wet. This forum is great...a lot of expertise and interesting viewpoints...everyone keep up the good work!"
 
so what if u ran a four stroke

so what if u ran a four stroke engine dry?

really wanna know lol!!!
 
"On a 2 stroke , when the fuel

"On a 2 stroke , when the fuel stops going into one cylinder how would the oil that is there know" I have to get out now " after all there is nothing but dry air coming in and going out??????????????????"
 
"Joel:
if carburated nothing

"Joel:
if carburated nothing will happen in the cylinder, but corrosion might start in the carbs. If fuel injected, a good way of destroying the injection system if left 'dry' for a longer period of time. Recommended is to use fuel stabilizer and fogging-oil mix for storage. (ref winterizing Evinrude/Johnson 4-strokes injected and Ficht's)
Ikia:
Are You in any way related to Don Quixote?"
 
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