Numerous times the experts have weighed in saying that there are no issues with todays fuel with regards to fuel lines and carb diagrams. I have mentioned myself though, that I certainly have had problems, and I often repair yard equipment and fully 90% of the problems with them that I find are rotten fuel lines and/or carb diaphragms gone stiff.

I recently needed to get my 25 year old chainsaw going quickly to help a friend that needed it. It had not been run in 5 years and in the 25 years I have owned it I have never once changed the fuel lines nor rebuilt the carb. (I swear that is true, and it has cut literally tons of wood.) I thought "there is virtually no way the fuel lines and carb are going to be ok, but I don't have time to service them so I'll just try to start it." There was some congealed oil/gas in the tank, so I poured some acetone in the tank, and let it soak while I checked/cleaned the spark plug. I then sloshed the acetone around, poured it out, and fueled the saw up. To my utter and complete amazement, it started on the second pull and ran perfectly!

I had the same thing happen with another chainsaw just the other day. A different saw I have hadn't been run in several years. On this one I needed to prime it with a squirt of fuel into the cylinder, but then it started up and ran on the first pull, and ran perfectly. I cut a bunch of wood with it with no problems.

Now on the other hand, I have had airplanes give me fuel system problems, sometimes in as little as 6 weeks of non-use. My brother had a plane with a Ryobi 31cc engine on it. He came to visit and we tuned and flew the plane. 6 weeks later he came back and it wouldn't run right. I fought with it for a bit, because I couldn't believe it could have carb problems after only 6 weeks of sitting. But finally I gave in and pulled the engine and carb, and sure enough, the diaphragm was "stiff as a board." I had a similar incident with my own Giles 30cc and other planes. It is really embarrassing for the local engine "guru" (ME), to show up at the field and have engine problems!! It was so bad that I finally started de-fueling all my planes after flying, and running them briefly on Coleman fuel with Sta-Bil and 20:1 Pennzoil before storing them. That solved all fuel system problems with all my planes. The neoprene fuel line in my fueling jug gets completely stiff on the part that is not submerged in gas. I have tried Tygothane, Neoprene, etc., but they all seem to be affected by the fuel to varying degrees.

So, either the materials in the fuel systems in those old saws was much better, or the fuel has changed and DOES affect carbs and fuel lines.

NOTE: I personally do not use, nor endorse, flying with Coleman fuel in any engine. (Yes, I know, some claim to use it with no problems. Not me.)

AV8TOR

Most of the time when people write about fuel related problems, they are blaming their problems on the ethanol in most fuels today. Many of us chime in and claim that the ethanol is not to blame for their problems.... and I stick with that claim.

On the other hand, modern fuels contain a whole list of what i would call hydrocarbon chemicals .... up to 35 are listed on some MSDS sheets. These various substances are blended into what is called modern gasoline and the blend can change depending on region, time of year and maybe what the refiner has an excess of and wants to get rid of. My belief is that these exotic blends are what is causing your fuel related problems. You simply can't burn a mixture that more closely resembles paint thinner than gasoline and not expect some kind of fuel related problems.

Summary, I believe your fuel system problems are real and fuel related .... and you've had more than your fair share of these problems. Probably the gas available in your area is the root cause.

Here in this part of the country, fuels seem to be more traditional and I just don't see fuel related problems. Same with fuels in northern Minnesota where we have a summer cottage. The equipment there gets little or no care and it always works. I have never rebuild a carb there and it is not unusual to use fuel mixes that are well over a year old. If fuel passes the "sniff test" and smells reasonably fresh, I use it. Maybe I'm just lucky?

Sometimes the ethanol level is very high in the fuel.

I sold a 4.2 cubic inch chainsaw to my son-in-law cheap. In the 25 years I owned it, I never had to replace any carb parts. The only items I replaced was the sparkplug & the fuel pickup in the tank.

It is very clear too me that rubber products was made of a very high quality in the old days. I am sure the companies that produce any product now, use cheap as possible rubber because they save money. Also they make very good money fixing theitems they sell. Sure you can buy new rubber parts...and they are way over priced too.

That old saw runs great even on the standard pump fuel sold in Michigan. So I call it the GREAT RUBBER PRODUCT RIP-OFF. Capt,n

I have had gas engines run great on the test stand while I ran them and broke them in some. Then I stopped running it and finished building a airplane and mounting the engine in it. A week later I take it to the flying field and discover, much to my dismay, that the engine won't run right. I rebuild the carb and it works great once again. I have had other engines run Ok for several weeks and then develop problems requiring a carb rebuild too.

I also suspect we have quite a few fake or counterfeit Walbro Rebuild kits out there in the world too. Such that the diaphragms don't last very long. Then you get lucky and find a real set and the parts last for ages without going bad.

My old crappy Poulan weed trimmer is still going strong after several years of use and abuse. it does take a lot of pulls to get it going after a long layover though. My cheap chain saw is similar and still seems to work irrespective of the treatment or lack of treatment it gets too. So sometimes I wonder if the RC engine companies are getting crappy rubber parts inside of the carbs versus what comes with the utility engines.

Capt,n

I don't agree with you at all regarding rubber parts being of a lesser quality than in the "old days".

For example, I remember in the 60's and 70's, on my cars, trucks, etc. I had to replace heater, water and gas hoses every couple of years as they got so hard and rotten, they would just break off or burst for no apparent reason. Today, I don't even remember the last time I replaced one of these hoses. Most of my vehicles and most of the fleet vehicles at work go to the end of their life with their original hoses in place.

The same applies to many other rubber parts ..... every example I can think of lasts longer than it did in the past. I would have to believe the same applies to the rubber parts in our Walbro carbs. Add to this, in the old days we didn't even have the exotic or synthetic rubber and plastic hose compounds we have today .... such as Viton, polyurethane, etc.

I don't believe the so called "rubber" parts are the problem here.

It's a vast right-wing conspiracy...

Tee Hee... I'm with you!!

And TruckRacer, I agree with you as well. It may not be the ethanol but other components in the gas, and I personally wish we could go to using ethanol in our vehicles as Brazil has been doing for many years. The, "THAT WILL MAKE OUR FOOD PRICES GO UP" is nothing more than gas company propaganda. I could fly you over thousands of acres of closed/abandoned farms here in Arizona that could be used for ethanol producing crops, and thousands and thousands more acres that are arable but have never been farmed. We could produce ethanol and cut the OPEC strangle hold on us, (once again like Brazil has), but the oil companies in effect prevent it.

As for the quality of the gasoline in general these days, it is horrible. I used to run 12:1 compression hot rods on the street and race track using only pump premium gas. Now, no matter what the octane ratings lie, you can barely get by with 10:1 compression using premium pump gas. I know it is not safe, but I often use gas to wash parts. The gas available nowadays will barely cut/clean grease!!!!

AV8TOR

12:1 compression hot rods on the street and race track using only pump premium

Now, Them were the day's !

Naaaaa ..... Left Wing socialist takeover!

b
I am talking about rubber parts related to small engines. I was not talking cars & trucks. Car companies got to place good cooing system hoses so they do not get a bad name. Also how about hoses on the real old John Deere tractors....seem to last forever. I do not care what you say...there is different qualities in rubber. I got a 70 year old continental army engine & the rubber is good as new like on the govenor boot. Also I inspected parts at a Military plant. The rubber parts had to be certified as to the date of MFG & meet military specks. Think & look around more.
Capt,n

Cap,

I don't doubt your experience. But, as a rubber compounder in an earlier life I can say with certaintly that some current rubber raw stockis animprovement over what was available say 30 years ago.

HOWEVER, some types of rubber, Hypalon for example, a stock that goes into high pressure hydraulic hoses and certain high temp belts among many other things including sheet, has had to change due to EPA regs. The change was not for the better in this case and no matter what we did as compounders, the finished goods didn't work as well as older rubber did.

Relating to rubber parts in Walbros, to me, it depends entirely on where they get their rubber part supplies and how good the supplier'scompounders are. Changes do happen over time and that includes the compounders/chemists. And with China making great headway into all markets, chemical supplies is another market play, for cheap.

Was it TR who said that there's whole bunch of additives in gas? Absolutely true....Gas milage has improved dramatically over the past 30 years, andgas additives along with lean running/fuel injected technology isa good starting place for that.

Yet another reason I don't mess with autogas; only avgas for me. That formulation has not changed in 70 years and is the same in CA as in TX as in MN as in NJ with no known seasonal effects. I ran a gallon of premium autogas once about a year ago when I found myself in a bind. But switched back as soon as I gota freshstash of avgas

Hey Matt, does avgas store any better than pump gas?

Definitely, but it's use in model airplane engines is questionable.

AV8TOR

Yeah, no kidding. I had one 401 in an AMX I built that was a bit over 12.5:1 compression. The cranking compression was 220 lbs.!! Ran just fine on premium. Won a bucket load of races with that car...

Yep, those were the days. Now I have a 454 "built to the hilt" Chevy in my Blazer. I built it with only 9.5:1 compression but still I have constant problems with detonation using premium fuel.

AV8TOR

Yes....consider how many planes are parked in the infield of any local airport and for how long. If they had to clean out gas tanks and change fuel lines every time they wanted fly, who would put up with that?
Actualshelf lifeis likely measured in years

In my experience I've stored Avgas as long as 9 months before using and it worked the same once I got going again. Nothing special done in that time frame. Kept it sealed in the plastic gas canand kept it in my garage through the seasons away from direct sunlight.

The formulation is for 100 octane Low Lead. As far as I know there is no "No Lead" available at this time.

It works fine in model gas engines, 30cc and larger. I have no personal experience with the really small gas engines so I can't say how it would do there. I've fed the stuff to all ofmine for 3 years and counting. Every 15 gallons or so I take the spark plug off and inspect. Usually it needs a little cleaning which is no big deal.

On tuning, if yours was well tuned running autogas, try avgas with the same setting first. It may need slight adjustment, usually leaner

Well... here's another fine mess you've gotten us into ollie. I don't think there is any scientific proof to any of this and it is very sporadic. Like the op I have a weed wacker and mowers that I never do anything special to for winter, and I leave gas in them and have never done anything to the carbs and they always start in the spring. I live in the heart of farm country and YES ethanol has driven up the corn prices dramaticlly and is forcing the small family farmers out of business and I can buy pure gas at my local station and Iget 10% better gas mileage. I all I know is whatI see and what Iexperience, your results may vary

AV gas has enough preservative in it for 5 years; pump gas 6 months. I dont worry about the ethanol doing damage; it is when it absorbs water and that does the damage. Fast temperature changes will make the water condense into the fuel the it is easily absorbed. AV gas tho is blended with some things, that while it is used constantly, everything is just fine, but let a diaphragm dry up after use and it accelerates the dry rot.

Yes, I can verify that if the Avgas evaporates, the rubber components will dry out very quickly. I have a race boat that I use Avgas in, and when it sits long enough for the fuel to evaporate out of the carbs, the "O" rings on the inlet needles in the Holley carbs dry out and shrink. Then when I go to start it, it floods like crazy and I have to remove and replace all four needle valve "O" rings. The accelerator pump diaphragms take a beating too. Though as a matter of fact, I just had this very thing happen on my Blazer as well a couple of weeks ago, and it only runs on premium pump fuel.

AV8TOR

AV8TOR.... I've expressed the same. My Homelite chain saw is thirty years old and has wore out one chain in that time so doesn't get a great amount of use, though it does get used several times a year for small yard projects. Absolutely no fuel or ignition issues with it.... it has never failed to start and run well.

On the other hand, I've a gas weed eater almost as old and it has seen a half dozen carb rebuilds so who knows?

What I know...engines that have good rubber made parts keep right on going....the engines that have cheap crappy rubber made parts need fixing way too much................. Capt,n

My DLE55 was run exclusively on avgas until mid 2011. Since then it's on the shelf, completely bone dry. I intend to run the 55 again this year so I'll get some first hand info oh how the walbro behaves. On your experience it's worth the time to take the walbro apart and feel the rubber. I'll post the findings, good or bad...

Well Captn, we'll just have to agree to disagree on some of these points. Like you, I've been around the block a few times and witnessed just as many examples of old rubber that has turned to dust or in some cases melted into a nice gooey pile of muck. I'm not sure any of these observations prove anything one way or the other though. I will maintain that any Walbro problems are more related to local fuel blends than any changes in the internal rubber parts. I'm sure you'll maintain otherwise and that's OK!

As far as Walbro parts go, I only use genuine Walbro kits and never any of the many that are available unbranded and in plain white bags, etc. I have several clone carbs though and no problems with them yet.... and who knows the source of the diaphragms in those carbs. As far as the Walbro kits, the included pump diaphragms are in some cases not even rubber but some other material in the case of the brown or blue ones. The brown one seems to be the most common these days, especially in the WT carbs.

That is what I use also...the brown or tan replacement parts. I think it was Antique that said some engines from china do have carbs that say Walbro...but there not. Kinda like the Hayes neopreme fuel line I got from Tower Boobies. The stuff turned worthless in about ten days. Not the real stuff I guess....but who the heck knows. Capt,n In Florida

I would like to see those.