Run out the fuel?

heyblue

Seaman Apprentice
Joined
Sep 4, 2012
Messages
48
Notice when I tilt up the motor for travel some fuel runs out into the rear (the engine well) of the boat. Two questions, is this fairly normal? What about shutting off the fuel and let run until carbs are out of fuel?
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I always ran my engines out of fuel after removing the fuel line connection to make sure the carb(s) were empty. I know a lot of folks say not to do that. But I never had any issues ever in all the years I own engines and boats... So we'll see what others have to say.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
What if the motor is oil injected.----Would you be filling the carburetors with straight gas on start-up?----Motors are not all the same.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Probably coming from air box.Unburnt fuel usually pools there via the carb throat.Usually there is a bleedline attached that sucks fuel back into cylinder.Depends what motor you got.
Running fuel dry is not a good practice.Cylinders need lubrication.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
Running a non oil injected motor out of fuel is consider very good practice.-----And there is lots oil in the motor when it turns before stopping.--Lots of oil and the oil that is in the motor just does not disappear in an instant.
 

heyblue

Seaman Apprentice
Joined
Sep 4, 2012
Messages
48
This WAS an oil injected motor, but that all has been removed and running on premix. Seems like if I just shut off fuel while I am flushing,( I run in only salt water) that should clear up my problem. I seem to remember long ago about running the fuel out, but not sure if that was just when storing. Would be interested in hearing more feed back on this. i.e. who did this and found it caused bad results?
 

Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,235
oil injection or not, is a non issue....mix happens before it gets to carburetors and/or injectors... as for a "dry start" it is to. oil doesn't dissipate while settin' like said.. if it did just think about all tha rust that would form in tha cylinders, bearings and crank.....

a little is normal with some motors but if its more than that ya may have a "float/needle n seat, leaky injector problem......

runnin' it till empty has been debated since "day one"....your choice...

motors "just set" everywhere, private and dealerships....very few do any more than addin' fuel/oil and runnin' 'em when tha time comes
 
Last edited:

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
More than anything this is why I like fuel injection over carburetors.

IMHO running them out of fuel is a great water to kill your motor prematurely. The carbs dont all run out at the same time and the top cylinders will be oil starved at the end of the process. Little bit here and there but it all adds up.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
When one of the carburetors runs out of fuel there will be lots of oil coating the bearings and inbetween the piston and cylinder wall.----This oil simply does not disappear in an instant !!!----Running a motor out of fuel ( premixed ) is a very good idea and good practice.---Keeps carburetors from gumming up.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
I would say find the cause of fuel spill before putting engine through undue stress.
Next time before tilting remove cowl and airbox cover and check for pooled fuel...if ok remove air box and tilt engine to see how much comes from carb throat.
Mine did the same and quite a bit too.Then I found previous mechanic??? had crossed bleed lines on air box and instead of sucking fuel from box it was blowing it in....saved me a lot of $$$ on fuel and constant headaches from endless fuel stench.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
If the needle valve in a carb, controlled by the float, is not seating properly, you will get this problem!
 

quicktach

Petty Officer 1st Class
Joined
Aug 24, 2012
Messages
394
Carb cleaning and check float needle and seat. Replace as required. I wouldn't run dry either.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Just thought I'd add another note concerning the running dry part.

I've been boating over 50 years. Had a boat before I had a car....used mom's. For about 38 of those years I always ran the carb(s) dry with the engine still in the water for the reasons mentioned in this post by others. Seldom did I ever do maintenance on any of my engines. Changing plugs periodically is about all. Never changed an impeller running salt and fresh water. Only lost one engine and it was on a used Evinrude I bought, mentioned recently in another post where the thermostat stuck shut (didn't even know it had one) and the engine had been run in fresh water all it's life.

My last engine was a 2002 Merc. 90, which I bought used at 2 yrs old. Since this was my first oil injected engine I thought it best to NOT run out the fuel because I wanted to ensure that upon startup I had the proper mix. The service manual I received with the engine said nothing about the process so that was no help. It was at that time that I learned of this site and joined it. As a result I started using Sea Foam and used it in every tank at the can recommended ratio of 1 oz per gallon of gas. I ran E-10 gas for the last 5 years at least and never had a varnished carb or piston gum up or carbon build up on the engine in the 10 + years years I had it. Maybe it was the Sea Foam.

Just my experiences.

HTH,
Mark
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
I have never seen a manual that cautions of running a tank dry / carburetors dry.---It is the best to run the carburetors dry to keep them clean.--Those that are paranoid just do not understand the finer points of lubrication inside a 2 stroke crankcase.
 

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
I have never seen a manual that cautions of running a tank dry / carburetors dry.---It is the best to run the carburetors dry to keep them clean.--Those that are paranoid just do not understand the finer points of lubrication inside a 2 stroke crankcase.


Understanding that if a 2 stroke motor is run empty the motor runs out of oil isnt a difficult thing to grasp. If thats OK with you then do it. I wouldnt. To each his own. I keep fuel systems clean the other way. By using them.
 

bilge rat jim

Petty Officer 1st Class
Joined
Jun 28, 2012
Messages
330
I have never seen a manual that cautions of running a tank dry / carburetors dry.---It is the best to run the carburetors dry to keep them clean.--Those that are paranoid just do not understand the finer points of lubrication inside a 2 stroke crankcase.
And i've never seen a manual that recommends running an engine dry.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
I have never seen a manual that cautions of running a tank dry / carburetors dry.---It is the best to run the carburetors dry to keep them clean.--Those that are paranoid just do not understand the finer points of lubrication inside a 2 stroke crankcase.

I think some of the guys that are on the business on here make a valid point of variances in carbs drying out and running the engine without fuel. Course the residual oil in the cylinders and bearings certainly should be adequate to cover that. However, storage and restarting could be affected and lack of oil on engine startups is widely known to be a leading cause of engine failures of all types. On storage I understand from the big guns on here that storage corrosion is the main reason the industry quit recommending 100:1 pre mix.

On paranoia, I'm not paranoid. I had a 2002 90 Merc. I ran once every 3 months or so for about an hour. Had a 20 gallon tank in the boat, always had some old fuel in it to burn, and since the engine was oil injected I never ran it dry.....my choice, not what I read somewhere. In 2012 I decided to pull the carbs and check things out. Zero gum, varnish, crud, anything but a little residual oil and gas. Why so clean? Must have been the Sea Foam.

Mark
 
Top