Wit's end with my outboard

[Hank42]

The original post was an issue with hard starting. The ethanol will eat away at the inner lining of a fuel hose creating a “soot” which gets into the fuel and thus flows into the carb jets. On short fuel hoses, such as in lawn mowers, doesn’t matter much. But in our dinghies with much longer hoses, more “soot” is created. Using ethanol free fuel eliminates this problem.

[rslifkin]

Originally Posted by Hank42

The original post was an issue with hard starting. The ethanol will eat away at the inner lining of a fuel hose creating a “soot” which gets into the fuel and thus flows into the carb jets. On short fuel hoses, such as in lawn mowers, doesn’t matter much. But in our dinghies with much longer hoses, more “soot” is created. Using ethanol free fuel eliminates this problem.

Using good quality, alcohol resistant fuel hose also fixes it. Really old fuel lines and the cheap crap often seen on small engines, outboards, etc. is often not sufficiently alcohol resistant and either dumps crap into the system like this, or it collapses internally and blocks flow as the inner layer gets eaten up.

[lituya1617]

Fuel injection is better in some ways than carbs but fuel problems are common to both. Fuel injection can be much more efficient; however, it is also much more complex and involves electronic computer-controlled modules, solenoid valves, high pressure pumps, etc. On a small engine, nothing fancy is needed. For many years, the most reliable small outboard has been the British Seagull. I have one that was made for use in the Second World War and it still runs well and reliably - it has a carburetor of the simplest possible design, a stainless steel centrifugal water pump, bronze lower unit gears designed to run with ordinary grease plus water in the housing - no rubber seals in the lower unit, an exposed flywheel with notch for a starting rope, etc. The low speed jet is adjustable with a knob as is the high speed jet. The carb has no filter and you can see the choke position directly. It runs on gasoline/oil 30:1 mix and uses any 30 weight oil you care to use. It starts with one pull and is 76 years old, my age. Carbs can be VERY reliable but you have to take care of them, empty them when the motor is not in use, and feed them good gas. I was given my Seagull because it did not run: problem was a lot of rust in the fuel tank. I put a couple of pounds of sheetrock screws in the tank with some automatic dishwasher detergent and water, shook the heck out of it for a while, rinsed it out, added a filter to the fuel line, cleaned out the carburetor, and it has run perfectly for the last 15 years. It always starts the first time, first pull.
I wish I started with one pull. Fancy and complex are not great choices for essential safety devices like outboards on a sailboat.

[bensolomon]

Thanks to the OP, and all of you for commenting. I have the same motor, a 2009 model, and still have the same issue despite a new upgrade carb (3.5 to 5). This thread has helped me immensely.

[thomm225]

Originally Posted by Hank42

The original post was an issue with hard starting. The ethanol will eat away at the inner lining of a fuel hose creating a “soot” which gets into the fuel and thus flows into the carb jets. On short fuel hoses, such as in lawn mowers, doesn’t matter much. But in our dinghies with much longer hoses, more “soot” is created. Using ethanol free fuel eliminates this problem.

That must take a lot of years then since I have had no carburetor problems in 10 years. (2011 Mercury 5 hp 4 stroke)

Of course my outboard was made to burn ethanol fuel though, but older models were not and the old hoses are a problem.

[Dieseldude]

Originally Posted by lituya1617

Fuel injection is better in some ways than carbs but fuel problems are common to both. Fuel injection can be much more efficient; however, it is also much more complex and involves electronic computer-controlled modules, solenoid valves, high pressure pumps, etc. On a small engine, nothing fancy is needed. For many years, the most reliable small outboard has been the British Seagull. I have one that was made for use in the Second World War and it still runs well and reliably - it has a carburetor of the simplest possible design, a stainless steel centrifugal water pump, bronze lower unit gears designed to run with ordinary grease plus water in the housing - no rubber seals in the lower unit, an exposed flywheel with notch for a starting rope, etc. The low speed jet is adjustable with a knob as is the high speed jet. The carb has no filter and you can see the choke position directly. It runs on gasoline/oil 30:1 mix and uses any 30 weight oil you care to use. It starts with one pull and is 76 years old, my age. Carbs can be VERY reliable but you have to take care of them, empty them when the motor is not in use, and feed them good gas. I was given my Seagull because it did not run: problem was a lot of rust in the fuel tank. I put a couple of pounds of sheetrock screws in the tank with some automatic dishwasher detergent and water, shook the heck out of it for a while, rinsed it out, added a filter to the fuel line, cleaned out the carburetor, and it has run perfectly for the last 15 years. It always starts the first time, first pull.
I wish I started with one pull. Fancy and complex are not great choices for essential safety devices like outboards on a sailboat.

Completely agree. Good old well designed, well made, and well maintained proven mechanically controlled engines are far superior to complex electronically controlled units. The are generally much more reliable. They are generally far simpler to understand and troubleshoot. Parts are generally less costly. No expensive computer modules, no complex array of sensors. Less electrical wiring. Test equipment is generally less costly and more readily available. Reliance on specialized knowledge and information is much reduced. The ability to do repairs in remote locations is much better. The older technology fits the application much better than modern electronic designs.

[rslifkin]

EFI holds a couple of advantages with small engines. It's only slightly more complex once you factor in all of the moving parts and small orifices in a carb. Basically, the advantages come down to most small carbs not being good carbs, so they're fussy. And EFI systems are much more sealed. Less fuel to air exposure greatly reduces fuel problems (with or without ethanol), especially if the engine is used intermittently.

[AiniA]

I fixed my Mercury 6 hp, 4-stroke, which is made by Tohatsu in places as diverse as Ecuador, Indonesia, and South Africa. In these places you whatever fuel is available (and yes we used a filter funnel. I got to the point where I literally could remove the carb with my eyes closed but never did since I didn't want to drop any of the bits. I found that the problem was clogging of the tiny jets. The solution we discovered was to use an acupuncture needle to ream out the jets. The needle are the perfect size and stiffness. You can buy them in Chinese stores (not groceries). They are meant to be disposable for acupuncture, so are cheap, but can be reused mulitple times as jet cleaners. One small package will look after you for years to come. Every time I did the cleaning and looked sternly at the carb the engine would work great for several months until the next time.

[Dieseldude]

Originally Posted by AiniA

I fixed my Mercury 6 hp, 4-stroke, which is made by Tohatsu in places as diverse as Ecuador, Indonesia, and South Africa. In these places you whatever fuel is available (and yes we used a filter funnel. I got to the point where I literally could remove the carb with my eyes closed but never did since I didn't want to drop any of the bits. I found that the problem was clogging of the tiny jets. The solution we discovered was to use an acupuncture needle to ream out the jets. The needle are the perfect size and stiffness. You can buy them in Chinese stores (not groceries). They are meant to be disposable for acupuncture, so are cheap, but can be reused mulitple times as jet cleaners. One small package will look after you for years to come. Every time I did the cleaning and looked sternly at the carb the engine would work great for several months until the next time.

The acupuncture needles are a great idea. Another great thing for cleaning small passages is a torch tip cleaner set. For anyone not familiar, these are made for cleaning the small gas passages of oxy-acetylene torches. There are a good range of sizes held in a jack knife stye holder. Each cleaner is wire like and is knurled all around, sort of like a miniature round file, but they are not sharp and will not cut into the passage walls. They can be had at welding supply and metal working tool supply shops.

[Catalacmarc]

Not familiar with the Tohatsu but I have ~20 years dealing with one genre of Yamaha 9.9s. I don't know if Tohatsus have the myriad push together electrical connectors under the hood as the Yamaha but corrosion on those is a common source of failures to start.



The other problem is a rough idle/stall that can develope, likely from clogged idle jets. What has worked for me is to carry a small fuel tank, four gals. I think,and put in twelve gallons worth of Chevron Techron additive in it. So far, every time I have run it through the engine for 20 or 30 min., it has cleared the problem. I know that common wisdom is that alcohol is at fault, but I also suspect seasonal variation in the formulation of gas loosening gunk in the carb and fuel system.

[Uncle Bob]

Have to say, I find it amusing that so many clearly haven't read the thread in it's entirety and offer opinions and solutions that have been offered multiple times with the OP detailing the path and result of those. I am firmly in the fuel flow camp and know just how much of a PITA the problem can be.

[JebLostInSpace]

Wow, this thread is amazing, thank you all so much for your input. No judgement to those who have commented without reading the whole thing, it's crazy long!

I finally have a weather and time window to spend more than an hour at a time on this project today, so I should be able to post updates!

To address a few questions already posted:
The vent is open and in good working order.
The fuel hose going to the carb delivers fuel when I disconnect and open the fuel valve.
My manual doesn't indicate the existence of a hidden valve on the back of the carb bowl. I'll double check when I open it up today.

My plan for today:
1. Actually remember to drain the carb bowl before I take the carb off, and check for water in the fuel.

2. Take the carb off again and get the darn float taken apart, and clean up the pin valve.

3. Soak the whole assembly in carb cleaner while I look at other areas.


4. Replace the fuel again. When I replaced the first time, I used the same fuel jug that had old fuel in it. Maybe the jug had residual water in it? So I got a new jug which I will fill from today. I'll also work harder to get the internal tank cleaned out when I replace the fuel today. Because it's internal, it's a bit tough to clean thoroughly, but I'll do what I can.

5. Check the spark plug again. I'm pretty confident the spark is fine. It's a new plug and it lights the starter fluid reliably. But I'm giving the carb cleaner time to work, so I'll look again.

6. Hit the carb gaskets with a little vaseline to help them seal.

7. Reassemble and try it.

I'll post later today with the results. Thanks again to everyone who has posted with advice.

[JebLostInSpace]

Welp. My plan has immediately gone awry. I went to drain the carb bowl and it was dry. I then also noticed that the fuel filter bulb was empty. I made sure the vent was open, the fuel valve was on, choke on, a little bit of throttle. I gave it about 25 pulls, and I'm still not getting fuel to the filter or the carb.

I disconnected the fuel hose from the carb and pulled some more, still no fuel.

I'm not sure what might have changed, but I figure there's not much point trying to clean out a carb that's not getting any fuel. So I'll be trying to trace this new problem. If anybody has any ideas on something I might have screwed up to suddenly cause this, I'd love to hear it.

[rslifkin]

Originally Posted by JebLostInSpace

Welp. My plan has immediately gone awry. I went to drain the carb bowl and it was dry. I then also noticed that the fuel filter bulb was empty. I made sure the vent was open, the fuel valve was on, choke on, a little bit of throttle. I gave it about 25 pulls, and I'm still not getting fuel to the filter or the carb.

I disconnected the fuel hose from the carb and pulled some more, still no fuel.

I'm not sure what might have changed, but I figure there's not much point trying to clean out a carb that's not getting any fuel. So I'll be trying to trace this new problem. If anybody has any ideas on something I might have screwed up to suddenly cause this, I'd love to hear it.

It's possible there has been a clog or issue upstream of the carb all along and it's just plugged up worse now. I'd start by inspecting all of the fuel lines. If any are questionable or not flowing freely, replace them. Once those are confirmed good, see if you get fuel from the internal tank to the output side of the tank selector valve. If that's good, might be time to look at the fuel pump.

[bgallinger]

Jeb, I feel your pain! I had a 5HP 2 stroke Evinrude that did the very same thing as yours and it made me crazy. I never knew when or if it would start. I spent hundreds of dollars on mechanics and "spring tune ups" all to no avail.
FINALLY, I tried a mechanic in Georgetown, Exumas who was not recommended by anyone. Well, he FIXED it once and for all. The problem was a bad kill switch! It started first pull every time after that.