Thinking about carbs

[HalcyonS]

I was cruising fleabay this morning and happened across listings for carbs for stationary engines and motorbikes - honda, subaru etc. Some will have seen my posts about precipitation of dissolved goop in modern fuel in my carb. I'm wondering if 'modern' carbs are somehow resistant to the goop the gets through my 3 filters. Has anyone else thought about this idea? A custom adapter plate would probably be required - that is a small thing. More important, obviously, would be specking the 'right' carb. What doyou think? Are modern carbs of this sort that different/much improved from the old zenith?
Just mulling this over...

[joe_db]

My lawnmower, outboards, and chainsaw have all suffered from ethanol gas over the years. There is no magic carb that will solve your issue IMHO.
OTOH my A4 has not had a bit of carb trouble in years. Whatever is the source of the goo in your system needs to be addressed.

I was cruising fleabay this morning and happened across listings for carbs for stationary engines and motorbikes - honda, subaru etc. Some will have seen my posts about precipitation of dissolved goop in modern fuel in my carb. I'm wondering if 'modern' carbs are somehow resistant to the goop the gets through my 3 filters. Has anyone else thought about this idea? A custom adapter plate would probably be required - that is a small thing. More important, obviously, would be specking the 'right' carb. What doyou think? Are modern carbs of this sort that different/much improved from the old zenith?
Just mulling this over...

[tenders]

The only solution to this is a paleo diet.

[rickandlee]

Gasoline type

I've been running Aviation fuel in my small engines for several years and have not had the carb issues of the past. We can get it at the pump at many stations here in Lake Havasu City. They also call it racing fuel. I've been doing all of my run testing of the A4 using this fuel but at $6.00 a gallon probably won't be using it all of the time.

No matter what fuel delivery system to the cylinders you use the fuel has to go through a small orifice Anything in the fuel that sticks too, or is larger than the orifice will cause a problem.

I'm guessing you have checked on components on the carb side of your filters, ie fuel pump diaphragm deterioration, copper tube between pump and carb internal deterioration, etc. I was amazed at what silicone sealant did to some copper pipe on a household project.

[joe_db]

IMHO you have these possibilities:
1. Some *liquid* contamination that goes through filters and settles out in the carb.
2. Some source of contamination after the last filter.
3. Your filters are really really bad at filtering.
4. The carb has ages to the point alcohol reacts with the metal to form a whitish goo paste. I have solved that on my boat and a friend's with a new carb.

I would very strongly suggest cleaning the carb and rigging a temporary - and CLEAN - outboard tank with known good fuel.

[ndutton]

Ethanol again?

Ethanol is often the go-to scapegoat for fuel system problems but other than the two known issues of E10 in boats (old fiberglass tanks and non-rated fuel hoses) can anyone cite a definitive cause and effect study conclusively faulting ethanol for anything?

edit: I should have said anything out of our control. For example, we know our fuel hoses must be ethanol rated so anyone who hasn't upgraded theirs deserves what they get. Sorry if it sounds harsh but it's the truth.

https://www.fuelfreedom.org/wp-content/uploads/Ethanol-Facts.pdf

Simon, I can't help but notice you've been dealing with this for over a year. Whatever you've been doing and replacing, the problem persists so the remaining question is what hasn't been done?

http://www.moyermarine.com/forums/showthread.php?t=9307

http://www.moyermarine.com/forums/showthread.php?t=9886

[HalcyonS]

The only solution to this is a paleo diet.

lol. lol. lol.

[HalcyonS]

For example, we know our fuel hoses must be ethanol rated so anyone who hasn't upgraded theirs deserves what they get. Sorry if it sounds harsh but it's the truth.

https://www.fuelfreedom.org/wp-content/uploads/Ethanol-Facts.pdf

Simon, I can't help but notice you've been dealing with this for over a year. Whatever you've been doing and replacing, the problem persists so the remaining question is what hasn't been done?

http://www.moyermarine.com/forums/showthread.php?t=9307

http://www.moyermarine.com/forums/showthread.php?t=9886

Hi Neil
thanks for the polite note. My last post was just idle musing.
Having cleaned what I suspect might have been a tiny speck of rubber hose torn off by a hosebarb, system is working fine at present.

My experience is that if I leave my engine without running it for over 2 weeks , I begin to have trouble starting. Previously, (twice) Facet ball valve was stuck - and my polishing filter was upstream of the facet. Now with my new Airpax pump, and polishing filter as close as it can be to the carb, things are fine. Will update as appropriate.

BTW - not harsh, no prob, but what is the spec of ethanol resistant fuel line?

[joe_db]

The rating system exclusively for marine hose is known as SAE J1527 and it provides for grades as follows:

A1--fuel feed hose; has a fire resistant cover; is designed to have fuel in the hose at all times. Least permeable with highest fire resistance.

A2--fuel vent hose; has a fire resistant cover; is not designed to have fuel in the hose at all times.

B1--fuel feed hose; without fire resistant cover; is designed to have fuel in the hose at all times; intended for non-enclosed spaces. Diesel engines or above deck outboard gasoline applications.

B2--fuel vent hose; without fire resistant cover; is not designed to have fuel in the hose at all times. Diesel vent lines.


Merry Christmas

[HalcyonS]

The rating system exclusively for marine hose is known as SAE J1527 and it provides for grades as follows:

A1--fuel feed hose; has a fire resistant cover; is designed to have fuel in the hose at all times. Least permeable with highest fire resistance.

A2--fuel vent hose; has a fire resistant cover; is not designed to have fuel in the hose at all times.

B1--fuel feed hose; without fire resistant cover; is designed to have fuel in the hose at all times; intended for non-enclosed spaces. Diesel engines or above deck outboard gasoline applications.

B2--fuel vent hose; without fire resistant cover; is not designed to have fuel in the hose at all times. Diesel vent lines.


Merry Christmas

Joe
thankyou. I was interested in the specs of ethanol resistant hose.

[joe_db]

That hose IS ethanol resistant.

http://standards.sae.org/j1527_201102/

[sastanley]

That post from joe might be worthy of the specifications thread.

[Al Schober]

IMHO, the problem is not with new hoses or old carbs - the fuel is the beast! Personally, I hate the alcohol fuels for marine or occasional utility use. For a car getting new fuel every week, alcohol fuels are OK. Otherwise they're trouble. This year I just may go to a regimen of turning off the engine by shutting off the fuel - run the carb dry. Then shut off the ignition. This regimen has worked for my snow blower - started this Winter on the second pull of the cord.
Every A4 owner should have the capability of pumping a jug of fluid from the bottom of the fuel tank. The engine is fed from a dip tube that doesn't go to the bottom. You need another tube (and a way to get it into the tank). Pump the tank as often as needed to identify & remove any water problems. My conditions improved considerably after replacing the O-ring on my fill cap.
Water separating fuel filter - IMHO a waste of money. The fuel tank is a better separator and has larger capacity.
Fuel filters are a good thing. Replace them often - at least every other year. Even with clean fuel, they're mostly made of steel, will corrode, and will send KRUD into your carb. Carbs don't like KRUD. I'm still looking for a filter between the fuel pump and carb that a magnet won't stick to - they all seem to be steel.

[Administrator]

That post from joe might be worthy of the specifications thread.

Done.

Bill

[joe_db]

I have been doing this for years. In the dinghy I pull the hose off the engine and let the outboard run until it quits. On the big boat I turn the fuel pump off and let the engine run until it quits.
As for water separating - the ethanol fuel has really made a mess out of this concept and then some
At the point you have enough water in ethanol-gas to separate, you also have all the ethanol mixed with water. This makes a terrible unburnable gooey mess that in my unfortunate experience, either makes it through the filters and makes the engine quit or clogs the filters and makes the engine quit.

IMHO, the problem is not with new hoses or old carbs - the fuel is the beast! Personally, I hate the alcohol fuels for marine or occasional utility use. For a car getting new fuel every week, alcohol fuels are OK. Otherwise they're trouble. This year I just may go to a regimen of turning off the engine by shutting off the fuel - run the carb dry. Then shut off the ignition. This regimen has worked for my snow blower - started this Winter on the second pull of the cord.
Every A4 owner should have the capability of pumping a jug of fluid from the bottom of the fuel tank. The engine is fed from a dip tube that doesn't go to the bottom. You need another tube (and a way to get it into the tank). Pump the tank as often as needed to identify & remove any water problems. My conditions improved considerably after replacing the O-ring on my fill cap.
Water separating fuel filter - IMHO a waste of money. The fuel tank is a better separator and has larger capacity.
Fuel filters are a good thing. Replace them often - at least every other year. Even with clean fuel, they're mostly made of steel, will corrode, and will send KRUD into your carb. Carbs don't like KRUD. I'm still looking for a filter between the fuel pump and carb that a magnet won't stick to - they all seem to be steel.