Mercury Outboard - Four Stroke

rail · December 31, 2011, 09:51:54 AM

My 15hp, four stroke, outboard will not idle unless the choke is engaged. Any other four stroke outboard owners with the same problem? :(

Shanevrr · December 31, 2011, 11:24:25 PM

sounds like lack of fuel, clogged filter, carb gummed up from crappy fuel. Can you take carb bowl off and spray carb cleaner through needle. Remove float, just dont lose the little pin that holds float in place

Sundog · January 01, 2012, 12:03:11 AM

Vacuum leak?

rbinhood · January 01, 2012, 10:17:29 AM

Diaphragm in your fuel pump has a small hole in it.

AllenF · January 02, 2012, 09:00:13 AM

Have you been running pure gas or corn gas in it?

rail · January 02, 2012, 10:14:50 AM

Quote from: AllenF on January 02, 2012, 09:00:13 AM
Have you been running pure gas or corn gas in it?

The first two hours on the engine was with 10% corn gas! Just switched to pure gas and it idles a little better now.

Seems there has been issues with the new four stroke outboards and ethanol fuel! :-x

AllenF · January 02, 2012, 10:20:44 AM

I just put my small chain saw in the shop because of ethanol. One day it would not hit but half a lick and when I let off the throttle, it died and would not fire again. Don't let that stuff sit for more than a couple of months.

don2 · February 26, 2013, 10:28:34 PM

Any thing you have that don't get cranked up and run at least once a week, "DON'T" use corn sipping s in it. Been there, done that. don2

Nimrod · April 04, 2013, 11:08:33 PM

I have a new Merc 9.9 and I run reg. gas (not 10%) with Sea Foam added. I have ran this mixture in all my other small engines and it has not failed.

divemaster1963 · April 04, 2013, 11:44:07 PM

I'm a small engine mechanic.
Gasohol draws moisture like a paper towel. never leave it in your engine more than a week without running it for at least 30 min. because it made from corn it also molds! It will turn the inside of the carburetor green and plug every hole in it. use green stabil with the gas. never buy more gasohol than you can use in a day. when you finish use your equipment run it dry and spray seafoam in the carb and cylinder. do this and your equipment will last.

John

AllenF · April 05, 2013, 07:02:05 AM

Or make the drive over the state line to Alabama and buy pure gas. :-D I stocked up for spring on my last fishing trip.

RC · April 05, 2013, 08:17:58 AM

Dumping groceries in your gas is never a good idea.

bailey · April 05, 2013, 08:23:43 PM

Just got my outboard out of the shop because of corn gas.
Won't run it again!!!

Ben Framed · December 07, 2022, 07:20:55 AM

Well folks it is apparent ethanol is not the fuel for the outboards described here. Have you faced any problems because of using it in other equipment such as chain saws, lawnmowers, blowers, etc?

Phillip

Michael Bush · December 07, 2022, 12:08:22 PM

I never use ethanol gas in small engines. Also try to empty them before winter sets in and they set. No gas ages well and ethanol is even worse. Buying engineered fuel and using it for what you think is the last time for the season also helps.

BeeMaster2 · December 07, 2022, 01:13:02 PM

I run pure gasoline in all of my farm equipment. I used to buy corn gas but I quickly learned that it destroys rubber o-rings and fouls up the carburetor any time you leave them sit.
Right now it costs almost a dollar more than regular corn gas. All of that is in taxes. This is exactly opposite of what is normal. We buy off road diesel tax free but this is an extra heavily taxed. That is our great environmental government.
Jim Altmiller

Acebird · December 07, 2022, 04:47:39 PM

Quote from: BeeMaster2 on December 07, 2022, 01:13:02 PM
I run pure gasoline in all of my farm equipment.

It is hard to find down here. You have to go to the coast and get rec 90. Because it is used in boats it costs much more but the cost is not a problem it is the storage having to keep another fuel can around and separate.
That being said I run the corn gas in my Merc 90 and not experiencing problems yet. Once a year I syphon the bottom of the tank.
Small engines like week whackers are a PITA because the ports are so small.

Ben Framed · December 07, 2022, 04:57:09 PM

Brian when I can not find (real gas). I add Sta-Bil in my lawn equipment fuel, both 2 and 4 cycle engines hoping for some type of protection. So far it has not let me down.. 'fingers crossed'

Phillip

Acebird · December 07, 2022, 07:56:12 PM

What has worked for me is taking a dremil tool and cutting a slit in the H and L needle valves and opening them up. These engines are fuel starved to begin with.

Jim134 · December 08, 2022, 05:43:45 AM

Quote from: Acebird on December 07, 2022, 07:56:12 PM
What has worked for me is taking a dremil tool and cutting a slit in the H and L needle valves and opening them up. These engines are fuel starved to begin with.

The only place I know you can buy real gas.. Is at an airport.. Just find a small airport near you.

BEE HAPPY Jim134 😊