mercury outboard wont start

[Tillerjockey]

If you ran all the gas out of the engine 6 months ago, it's probably not a plugged carburator. If you didn't it probably is... If it ran fine 6 months ago, it's probably not the spark plug, if the engine was sputtering, then check the plug. If the gas is more than a year old it probably needs to be replaced.

Most engine problems are either fuel or electric. I have had a few mercury outboards and have found them to be reliable with proper maintenance.

[JOHNMARDALL]

In South Florida, where I live, there are plenty of gas stations that sell gasoline without ethanol, so I wouldn't consider putting ethanol- containing fuel in any of my small-engine devices - the ethanol absorbs atmospheric moisture and on some engines, will damage fuel system seals.

As others have said, it's good practice to shut the fuel off and run the engine dry if it's going to sit for a while, to prevent lacquer forming in the float chamber and on the jet(s) as the fuel evaporates or decomposes.
I have a Mercury 9.9 four-stroke and the choke pull has a small plastic linkage that has fallen off a couple of time and dropped into the bottom of the case. Even when hot, that engine will not start without the choke/slow-running pull being out a little (and connected).
Good luck
John Mardall
Vetus Maxwell Boat Equipment

[thinwater]

Originally Posted by winschwab

I have a 2015 3.5 and a 2016 6.0 Tohatsu. I run non-ethanol with Stabil and still have lots of trouble. Often hard to start, but not consistently. Often acting starved for fuel: will only run with choke half way out. I have disassembled and reassembled the carb re manual instructions, but I'm not sure I'm really getting at the problem. Any more suggestions?

Stabil is not one of the brands that tested well, but they do advertise a lot. Biorbor EB or Merc Quick Stor are measurably better.



https://www.practical-sailor.com/iss...n_10855-1.html


On the other hand, some companies just like to spend time in court. I'd avoid such companies.

https://verdictsearch.com/verdict/ne...-dispute-jury/

[mario f]

Originally Posted by thomm225

Ethanol will work fine (it's what the engine was built to use),

Ok, this goes contrary to what I have been told and advised.
Can you explain why it is ok to use ethanol in fuel.
Not looking for an argument, I just need to know.
Thanx

[thinwater]

Originally Posted by mario f

Ok, this goes contrary to what I have been told and advised.
Can you explain why it is ok to use ethanol in fuel.
Not looking for an argument, I just need to know.
Thanx

I've used nothing else from the start. The thing about e-10 is that there are rules. The are not hard to follow, but you must do it.


Ethanol does three things. If enough water gets in the tank it can separate; make sure there are no cap leaks and close the vent when not using. Ethanol increases corrosion by increasing the amount of dissolved water AND increasing conductivity (ions can move; keep the gas dry and use an anti-corrosion additive. E-10 has greater vapor pressure and evaporates faster; keep the vent close when not running and run the motor regularly. Finally, the copper ions created by trace corrosion (remember, you have brass jets in an aluminum bowl--a bad combination) are a powerful gum formation catalyst; the MOST important steps in preventing gum are keeping the fuel dry and preventing corrosion with a good additive. No copper ions, no gum. You can keep e-10 in a glass jar forever with little gum. It is the metals that cause the trouble.

• Fill the tanks AFTER every use. Less breathing room means less water absorption. Not vital if for portable and integral tanks.
• Close the tank vent and fuel valve after every use, if possible. A single hard rainstorm can ruin the tank if the vent is open. Just a ew drops of water is a big deal in 1-2 liter tanks.
• Use a good additive (Biobor EB or Merc Quick Stor).
• Run the engines frequently. Every month really helps. It keep the gas fresh (evaporation) and solves minor water problems.

[De.windhoos]

Originally Posted by bimini blue

so this is a bad on me, we cruised in June got back at the end of the month
the dinghy outboard went on the stern pulpit,
it is now December and I have not cranked it in at least a couple of months and of course it wont start

any tips
do I put a little ether or starting fluid
clean the plug
would rather not have the mechanic come out

thoughts

Buy a spray bottle of Carb cleaner and clean the carb, very easy and loads of youtube video's to help you figure it out.
Also clean (blow through) the little fuel filter.

In the future, if you know you are not using your outboard for more than a week or 2, do the following:

1. Start the outboard
2. Close the fuelcock
3. let it run until it stops
4. take the cover of and drain the last fuel from the carb, there is a little screw for that at the bottom of the carb.

And if you are on salt water and really like your outboard than flush the outboard with sweet water. you can place a large bucket or cut up fender over the tail section and put a water hose in it. Then run step 1 through 3. This will help avoid fouling the cooling water system.

[CAR54]

The 3.5 Tohatsu outboard I own had the same problem your experiencing, due to not running the carburetor dry for storage. After pulling the carb completely a part spraying it with carb cleaner and installing, it would start but run ruff and needed the choke pulled out a little to smooth it out.

After living with it this way two years, I bought a new carburetor for it and now it starts and runs like new.

Lessons learned, never run ethanol fuel in small engines at sea or land and always put fuel stabilizer in before storage, running the engine to ensure the fuel system is completely protected. Then shut off fuel and run engine until it quits from from fuel exhaustion.

[mario f]

Thinwater,

Thank you for the response, complete and concise.

[thinwater]

Originally Posted by De.windhoos

Buy a spray bottle of Carb cleaner and clean the carb, very easy and loads of youtube video's to help you figure it out.
Also clean (blow through) the little fuel filter.

In the future, if you know you are not using your outboard for more than a week or 2, do the following:

1. Start the outboard
2. Close the fuelcock
3. let it run until it stops
4. take the cover of and drain the last fuel from the carb, there is a little screw for that at the bottom of the carb.

And if you are on salt water and really like your outboard than flush the outboard with sweet water. you can place a large bucket or cut up fender over the tail section and put a water hose in it. Then run step 1 through 3. This will help avoid fouling the cooling water system.

I should add that the deposits with ethanol are often corrosion products, not gum. If you see any corrosion pits in the aluminum bowl, this is a good bet. This means that carb cleaner will NOT dissolve them, they must be physically dislodged. Usually this can be accomplished with targeted blasts in the jets, starting from the down stream side.


Also, some small motors (<6 hp) do not have real filters, they only have a fine strainers in the tank outlet. Many sailors cut the fuel line and insert a $5 lawn mower filter. I added one to a 3.5 Merc I had and it helped a good bit. Easy to change and cheap. Keep a few spares.

[thomm225]

Originally Posted by mario f

Ok, this goes contrary to what I have been told and advised.
Can you explain why it is ok to use ethanol in fuel.
Not looking for an argument, I just need to know.
Thanx

Sure.

First off, the engine was built to use 10% ethanol.

Every old school (uneducated) mechanic will tell you it's terrible though.

My Mercury 5 hp 4 stroke outboard which I've had for 8 years has only run on ethanol and it has a carburetor. I've had no problems so far except late this past summer I had to spray out the carb without removing it to correct an idling problem.

I use the ethanol fuel every year that is left over from the year before in the Spring. I do treat it though with stabilizer in October/November. No special precautions are needed during the sailing season but if you are worried add some stabilizer

Just look at things mentioned on this post. One guy says use a rag in the carburetor. (when the engine already has a choke) He is following old school fixes also but this is 2018 not 1935.

It takes a long time for people to change and except a new thing.

[foggysail]

Originally Posted by a64pilot

Starting fluid isn’t needed, and if incorrectly used can cause damage.
Starting fluid was for way back when for Diesels without glow plugs, in cold weather.
Most often chokes don’t block off the intake completely and you can’t pull the strong vacuum you can with a rag.
Cleaning plugs often doesn’t work, they sometimes break down electrically internally and develop a short, and they usually aren’t that expensive, and your motor will likely run better with a new one anyway.

Starting fluid causes damage??? I doubt it. I have used it on various engines now for over 50 years. Never ever had a problem. It also works very well getting my tired old chain saws running. Just use it in a well vented area

[Rex Delay]

Did not catch your location but mine does this regularly if not run dry prior to shutdown. On the merc, there is a drain screw at bottom of carb. Open it and catch the drips. Probably dripping water for a while then gas. When dripping pure gas, close it up and you are good to go. Add a little methyl hydrate to the fuel.

[Tellie]

These little Mercs are famous for not starting or running if they sit too long. I agree with those above that say it's the carb. I've cleaned the carb on a Merc 6hp I have dozens of times. It's worth knowing how to do it. It's really simple and straight forward.

[Billnpr]

Had a Mercury 6 and now a Yamaha 8. Both have the same issue when I ran carbs dry with non-ethnol gas. Gas stays in the on engine gas line and filter. That little bit of gas evaporates and leaves little flakes that looks like dandruf. The flake clog the low speed jet. Take appart the carb and use spray carb cleaner to clean the jet after removing it. Almost as easy as changing spark plugs. Mercury should start right up. Last winter a made a point to run my Yamaha once a month and run the carb dry. The condition of carb cloging did not occour.

[a64pilot]

Originally Posted by foggysail

Starting fluid causes damage??? I doubt it. I have used it on various engines now for over 50 years. Never ever had a problem. It also works very well getting my tired old chain saws running. Just use it in a well vented area

Yes it can cause damage, I have used it forever too, but sparingly and acknowledge it can damage. I see no need of it on a boat and I don’t carry any.
Primary way it can damage is the ether combusts very quickly, much more quickly than gasoline and the sudden rise in cylinder pressure can blow a cylinder head gasket, break starters if electric etc.
Especially if a very rich mixture is ether is used, and or combusts well before TDC

It can be especially damaging if used on a Diesel with glow plugs, reason is it can be ignited by the glow plug, well before it would normally be by compression, so a piston can be well on its way to TDC, but well short when the sudden ignition of ether kicks it in the face, you have all the inertia of a spinning engine and its mass trying to compress gasses that are already at high pressure due to the ether combusting. It can be very similar to a hydrolock. I have seen cylinder head bolts broken, rods bent.

If you know what your doing and use ether correctly, it’s relatively safe.
Ideally you only use it sparingly on an engine that is already turning over, a tiny shot to get combustion started, and you may need another tiny shot or two to keep it going.
That is tough to do on a pull start engine.

However if you fix what is wrong with the engine, unless it’s a non glow plug Diesel and stupid cold, you don’t need starting fluid, at best it’s a band aid.

On edit, a quick google.
https://blog.amsoil.com/is-starting-...r-gas-engines/