Dinghy engine techniques

[Dougcole]

Ditto, sorta. But first, assuming your Suzuki is one of the newer ones, it's a) fuel-injected, and b) two cylinder. Both might be important distinctions.

Back to the regime. We can only get ethanol, so we've had to adjust our plan to that. Our one-cylinder two-stroke 5-hp Johnson (Suzuki) was susceptible to ethanol issues. Using the motor often, no problem at all.

But for longer period of disuse... No brand of stabilizer (including both types of Stabil) ever did squat. I usually let it run dry after use, but seemed to find no big difference between doing that and doing nothing. (I have more recently heard the theory about not running the carb dry, though, and would think there could be some factoid behind that. Certainly when gas dries, it can leave a kind of varnish... In any case, II noticed no particular difference.)


Anyway, we eventually started siphoning out any remaining gas after 3 weeks of non-use. Period. That pretty much ended the problems.

Starting over with fresh (ethanol) gas seems to work pretty well. Even if a little of the old remains in the onboard tank or in the external tank, that seems to become diluted enough with new gas so the carb and the one-cylinder motor can deal with it.

With our newer 15-hp Suzuki fuel-injected two-cylinder 4-stroke... so far no problems. But I've still been sticking to the recycle routine out of habit, so not sure I can say the fuel injection or the two cylinder might be part of the solution or not.

I do remember back 60 years ago or so, we never worried about the gas in our outboards. Didn't matter if it was a year old or more, didn't matter if the motor hadn't been used in 6 months or whatever, it'd start and it'd run.

Now? Not so much. At least with the smaller carbureted motors.

-Chris

You're right, my Suzuki is fuel injected. I forgot about that.

 

[FlyWright]

You would probably do better to pour that into your boat diesel tank. I wouldn't want that crap going through my car's fuel system. In your boat, it is better filtered and you have bigger tanks for dilution.

I don't want to ever pour gasoline into my diesel fuel tanks. I don't know its effect on the engines and it just doesn't sound or feel right. I'd rather throw it out than risk any issues in the boat.

 

[Heron]

But one thing I do is buy the high octane gasoline (yes, it has a 10% ethanol blend) so as the fuel ages and the octane drops, it is still high enough octane at the end of the season. .

I doubt octane has anything to do with this...In fact, higher octane fuels burn slower. I'd expect that most of these engines would run fine on 80 octane second world fuel. Compression ratios are low as are RPM's, and I've never seen a requirement for high octane fuels. You may get a slight benefit from additives that are in higher octane fuels..

 

[RT Firefly]

Greetings,
All this talk of draining fuel bowls and portable tanks and no-one has mentioned the gasoline that remains in the connecting hose. I was having problems starting an older 15HP Yamaha last year and one of the members mentioned that in spite of the fact I had run the carb dry and refilled the previously emptied remote tank I was STILL trying to start on that old fuel that had remained in the hose. Just a thought...

 

[DavidM]

Baker:

I disagree with your friend's advice to not run the carb dry. Here is why:

Gasoline will turn to varnish as it slowly evaporates in the fuel system. It does this due to a chemical reaction that causes the gasoline components to polymerize. It will do this with or without ethanol. I had it happen 30 years ago, long before we had any ethanol in our gas.

As it evaporates it leaves a varnish in any low lying spot- the bottom of the fuel tank, horizontal fuel lines, in the bottom of the float chamber and in horizontal needle valves. I have actually seen it in many of these places.

Before ethanol, it would take quite a while for the fuel to evaporate, let the varnish concentrate and then form a deposit in the low spots. Now with ethanol, this happens much quicker and the fuel doesn't need to evaporate- the varnish will form at any low spot where water will accumulate- usually the bottom of the float chamber.

So when you run the carb dry, you are removing fuel from most of the places where it can cause harm- the fuel line downstream of the shut off valve, the horizontal needle valve, but not the bottom of the float chamber. A tablespoon full of fuel will remain in the bottom. But that tablespoon of gasoline, ethanol and water can only form a tiny bit of varnish.

That tiny bit of varnish in the bottom of the float chamber will not affect operation of the carb. All of the small passage parts- the float valve and the needle metering valves are an inch or two above that point. If you run the carb dry then they are dry and will work fine once the carb is filled with gas. Often the fresh gasoline will dissolve the minute amount of varnish.

So, sorry for the long explanation. And FWIW this is what you do when you think that your carb is gunked up whether you run it dry or not:

Get a quart can of carburetor cleaner from your auto parts store. This stuff WILL dissolve the varnish. Then remove the carb, disassemble it, including the float valve and the screw jets. Dump all of the parts in the basket and soak for several hours. Remove the body and turn it upside down and soak for several more. This assures that any air bubbles are out and all passages get immersed in the cleaner. Reassemble the carb and 90% of the time it will run fine.

I am batting 5 for 5 with this procedure.

David

 

[Marin]

Marin is right, since I use non ethanol fuel it is probably overkill to drain my tanks before any sort of extended storage. But it is easy and cheap, so I do it rather than worry about bad fuel.

I've never had a mechanic--- automotive, aviation, or marine--- tell me that fresh lube oil is bad for an engine. I suspect these same people would never tell me that fresh gasoline is bad for an engine, either. So if you're happy with the routine of cycling the old fuel out every month or so then I can't think of any downside to continuing to do that as far as the engine's ease of use and reliability is concerned.

 

[Codger2]

I don't want to ever pour gasoline into my diesel fuel tanks. I don't know its effect on the engines and it just doesn't sound or feel right. I'd rather throw it out than risk any issues in the boat.

Could not agree more.

 

[Nomad Willy]

My fuel injected OB (60hp) never has an old stale fuel problem. Starts instantly and runs perfect no matter how long it's sat not running.

My little engines w carbs don't have a problem sitting except the 6hp Johnson. I run the engines (not motors) dry when they are going to sit for a while and most all the time run E10.

 

[Baker]

Baker:

I disagree with your friend's advice to not run the carb dry. Here is why:

Gasoline will turn to varnish as it slowly evaporates in the fuel system. It does this due to a chemical reaction that causes the gasoline components to polymerize. It will do this with or without ethanol. I had it happen 30 years ago, long before we had any ethanol in our gas.

As it evaporates it leaves a varnish in any low lying spot- the bottom of the fuel tank, horizontal fuel lines, in the bottom of the float chamber and in horizontal needle valves. I have actually seen it in many of these places.

Before ethanol, it would take quite a while for the fuel to evaporate, let the varnish concentrate and then form a deposit in the low spots. Now with ethanol, this happens much quicker and the fuel doesn't need to evaporate- the varnish will form at any low spot where water will accumulate- usually the bottom of the float chamber.

So when you run the carb dry, you are removing fuel from most of the places where it can cause harm- the fuel line downstream of the shut off valve, the horizontal needle valve, but not the bottom of the float chamber. A tablespoon full of fuel will remain in the bottom. But that tablespoon of gasoline, ethanol and water can only form a tiny bit of varnish.

That tiny bit of varnish in the bottom of the float chamber will not affect operation of the carb. All of the small passage parts- the float valve and the needle metering valves are an inch or two above that point. If you run the carb dry then they are dry and will work fine once the carb is filled with gas. Often the fresh gasoline will dissolve the minute amount of varnish.

So, sorry for the long explanation. And FWIW this is what you do when you think that your carb is gunked up whether you run it dry or not:

Get a quart can of carburetor cleaner from your auto parts store. This stuff WILL dissolve the varnish. Then remove the carb, disassemble it, including the float valve and the screw jets. Dump all of the parts in the basket and soak for several hours. Remove the body and turn it upside down and soak for several more. This assures that any air bubbles are out and all passages get immersed in the cleaner. Reassemble the carb and 90% of the time it will run fine.

I am batting 5 for 5 with this procedure.

David

Thanks for the advice. I am only going on my experience. I have been battling this in a Merc 2 stroke 15hp and a Yamaha 2 stroke 15hp ever since they introduced ethanol into our gas. The symptoms are EXACTLY the same. Since I have stopped running gas out of the engine I have had no problems. I don't have a lot of history, I will admit. But this last period of 4th of July to Labor Day of non use and then perfect reliability gave me some hope.

 

[FF]

"hate small gas outboard engines. I went to using an electric outboard on my RIB. I don't go fast, but I never have to keep gasoline on board anymore and it recharges with a solar panel, 12v, or 110. Also super lightweight."

Bigger advantage is the bride wont feel she is trapped aboard as the electric trolling motor always starts.

 

[High Wire]

You would probably do better to pour that into your boat diesel tank.

This was a joke, right?
Really bad idea from a safety point of view.

 

[jleonard]

I never run the engine dry except at winter (seasonal) storage time. I treat ALL my gas for my dinghy engine, lawnmower, snow blower, etc. with Stabil. Never had a problem.
We have had only ethanol gas for many years around here (Ct).

 

[ranger58sb]

Greetings,
All this talk of draining fuel bowls and portable tanks and no-one has mentioned the gasoline that remains in the connecting hose. I was having problems starting an older 15HP Yamaha last year and one of the members mentioned that in spite of the fact I had run the carb dry and refilled the previously emptied remote tank I was STILL trying to start on that old fuel that had remained in the hose. Just a thought...

Yep. I picked up a couple spare fuel fittings, so I can stick one of those on the end of a disconnected fuel hose so it'll drain on my 3-week schedule. And when winterizing.

-Chris

 

[Baker]

This was a joke, right?
Really bad idea from a safety point of view.

Nope...not a joke. 2 gallons of gasoline in a 100 gallon+ tank is not going to affect much of anything. Now, I have never done it. But I did start a thread awhile back about what people do with old dinghy gas and quite a few on here made this suggestion. So search for that thread.

Edit:I went and read that thread. Only one suggestion of putting it in boat. The rest said to put it in car. I'm getting old and forgetful!

 

[Codger2]

. Since I have stopped running gas out of the engine I have had no problems.

Like any debate, there are always at least two schools of thought that can be put forward. I have found in the past that the "varnish" in the carb is the result of gasoline drying out and leaving a deposite. (Varnish) This doesn't seem to happen when storing your motor "wet."

 

[Marlinmike]

We take our dink motor off and it lays down, so we run out the fuel so it doesn't leak all over the deck, but we do use it alot and have no issues.

We use Staybil 360 for lawn mowers, snow blowers and classic car, no issue there either.

 

[FF]

Oars don't mind ethanol , unless you drink it.

WE have a Grumman Aluminum sailing dink and can visit harbors , near the shore , and no one throws rocks for the wake or stench.

With fenders lashed inside it does double duty as self rescuing life boat offshore.

 

[what_barnacles]

I read on a thread on here that gas added to the diesel tank would prevent algae growth. I think it was 10 gallons gas to 200 gallons diesel.

 

[Marin]

I read on a thread on here that gas added to the diesel tank would prevent algae growth. I think it was 10 gallons gas to 200 gallons diesel.

Algae does not grow in diesel fuel. Algae needs light to grow. What grows in diesel (and jet) fuel are bacteria and other micro-organisms. These micro-organisms tend to live at the water/fuel interface in the tanks, living in the water and feeding on the fuel as I understand it.

There are a number of biocides available as fuel additives to prevent this growth or kill it if it has occurred. One of the most popular in this area with boaters is Hammond's Biobor JF.

 

[SCOTTEDAVIS]

When storing for any amount of time I use 100LL aviation fuel, generators, boat motors, chain saws, motorcycles. Add a gal or less, start turn off gas or let it run out depending on the type of fuel system.

Been doing this for over 20 years now and never had a problem with any equipment. Airplanes sit for a long time and you never hear of av-gas going bad. 100LL will even clean out the crap left from auto gas.

You can purchase it at any FBO at your local airport, here we even have gas stations that sell it due to all the air-boats that use it.

When it evaporates it does so clean like naphthalene or vodka, 5 gals will take care of everything. My dingy has 3 gal of it right now.

Not for use with a catalytic converter as it has lead in it of course.

 

[markpierce]

Just be sure the bottom of your dinghy doesn't drop away, sending the battery as deep as the motor-battery cable is long.

 

[Datenight]

I never run the engine dry except at winter (seasonal) storage time. I treat ALL my gas for my dinghy engine, lawnmower, snow blower, etc. with Stabil. Never had a problem.
We have had only ethanol gas for many years around here (Ct).

+1

Rob

 

[markpierce]

With Ray at the oars, there's no need for a mechanical engine.

 

[drb1025]

I always purchase non-ethanol gas for use in my 20hp Honda outboard. I use Stabil every time i purchase gas. I generally run the engine dry if not using it for more than a week or two, but sometimes I forget. Either way, it always starts.