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Captain Bill · 29-05-2010, 08:52

I didn't want to hijack the unreliable outboard thread so I thought I would start a new one. Recently an outboard mechanic suggested to me that if I used the proper fuel additive it was no longer neccesary to run my carb dry on my outboard despite recent issues with Ethanol in the gas. I began experimenting and have observed that I do indeed have more issues when I run the carb dry than when I leave it full. After running the carb dry and leaving the engine sit for as short as one week I find that the float needle valve sticks in the open position. If I take the carb apart and clean the needle valve and seat it starts on the first or second pull. If I don't the needle valve sticks open and the carb vents fuel when I pump the bulb and the engine won't start. When I leave the carb full(using the afore mentioned fuel treatment) I don't seem to have this problem. I have run the carb dry on my outboards for nearly 40 years, but I am about to change my practice. I was wondering what the view of the forum might be on this.

djmarchand · 29-05-2010, 09:08

While I too have run the carb dry for more than 40 years with 100% positive results, I have heard of the argument against doing so that you mention. I guess it depends on the outboard. If you can run it dry without the needle sticking, then do so.

I do know from experience the effects of leaving fuel in the carb long term and they are always bad- it leaves a residue from fuel evaporating in the small passages which necessitates a carb tear down and degunking.

Like they say- you pay your money and you take your chances.

Davidi

delmarrey · 29-05-2010, 11:38

Like said above, it may depend on the motor.

Last year I bought a new propane weed eater due to the new fuel clogging up the carb even though I ran it dry at the end of the season. I've had a few small motors recently that have acted differently to the 10% ethanal. These are my observations:

The old weedeater would plug up just running the 10% E fuel. I had to clean the carb each time I used it.

A (4 stroke) Honda 9.0 OB would also plug up just running the 10% E fuel. The old fuel, it ran great for 10 years.

A Volva Penta OB would plug up just running the 10% E fuel. The old fuel, it ran great for 20 years. I would run it dry at the end of season.

The (4 stroke) Yamaha generator I have to run dry or it fouls up. I could leave the 0% E fuel in all winter w/o a problem.

An old Evinrude 5 hp I have to run dry or the oil/gas mix dries up leaving a sticky goo in the carb. So far the 10% E fuel hasn't been a problem.

When I take a part these carb's, what I'm finding is a white crusty deposit in the carb jet after running the 10% E fuels. The Honda was so bad that I carried two extra jets and would change them out when the motor started running bad and then cleaned them out when I found time.

In the old days it seemed the fuel companies would take pride in who had the best fuel. Now it seems they see how cheap they can make it and stay within the standards.
Recently I've been looking for a propane or diesel generator. I'd like to be done with gasoline on boats.

FSMike · 29-05-2010, 13:28

A lot of it may have to do with time. I might not bother to run the fuel out for a period of a week but I definitely would if I wasn't going to run the engine for several months. I think having a full carb/fuel system for that long would just leave more residue to gum up the works.

DeepFrz · 29-05-2010, 13:30

I know this doesn't contribute to the poll, but I have heard that using aircraft gas works wonders. It eliminates the ethanol problem anyway.

Astrid · 29-05-2010, 22:12

Avgas is more expensive though than automotive petrol. The two most common grades you are likely to find easily are 80/87 and 100LL. Both are leaded fuels with TEL anti-knock additives (.5ml per gallon in the 80/87 and 1.2-2ml per gallon in the 100LL). The last time (a few weeks ago) that I bought 100LL for a flight to Seattle the price was $4.91/gal.

Opie91 · 30-05-2010, 02:58

Quote:

Originally Posted by DeepFrz

I know this doesn't contribute to the poll, but I have heard that using aircraft gas works wonders. It eliminates the ethanol problem anyway.

I don't know about other countries, but here in the US AvGas is a big no no for anything except aircraft. You should not even be able to purchase it unless you have an aircraft. It is true there is no ethanol, but as mentioned above it is full of lead, way more than regular leaded gas ever had.

As far as running an engine out of gas I agree with the depends on the engine crowd. I personally run my 2 stroke Yamaha out of gas every time.

Although some 4 stroke outboards do not like you to run the engine out of gas, even for winterization.

donradcliffe · 30-05-2010, 03:38

It porbably does depend on the engine. I always run my Tohatsu 18 dry and it gives me no problems. I helped a friend get his Yamaha 15 Enduro running, and the carb float was stuck to the bottom of the chamber in some fuel residue. He said that he had run it dry, but there was enough fuel left to gum up the works when it dried out.

Liam Wald · 30-05-2010, 05:48

Do new outboards even have a carborator?

RedBellies · 30-05-2010, 06:13

I voted yes, but I only run it dry before hanging it up for the winter. It usually doesn't sit unstarted for more than 4 days at a time March-December and I use stabilizer year round just in case.

MarkJ · 30-05-2010, 06:19

I am a bit surprised. I never run my carb dry. Its a waste of fuel, money and wrecks the environment.

I must be missing the point, or I am a goose.

When you pull up at the boat instead of turning the engine off you just turn the fuel off and wait for it to stop?

pulyajibon · 30-05-2010, 06:44

If I disconect my fuel line from the Tohatsu 9.8 it takes 6m 34seconds for it to stop running.

Opie91 · 30-05-2010, 07:05

I dont run my carb dry when we are out cruising, but if leaving the boat for a week or so I do. I would say the run dry thing is for us weekend guys not the hardcore full time cruisers.