Odd 2 cycle gas issue

[Chester11]

Hey folks:

To save a few bucks over premix, I mixed up some fresh non-ethanol gas and plain jane 2 cycle oil (I think it was Car Quest or something I picked up at Advance). After running about a 1/4 of a gallon, my 5 year old blower (Hitachi) is now stalling - if you choke it a bit it seemed to run better. It sounded fuel starved, but here is the weird part - I added a few ounces of pre-mix and it runs fine.

My mix runs fine in my other blower - so now I'm really confused. I always thought 2 cycle oil was 2 cycle oil. And I would think if the fuel / oil was bad - the problem would happen in both.

Where do I start? Buy an electric? Is one just more sensitive to octane? (We only have 90 octane non-ethanol here, the premix is 94 I think).

 

[wpod]

I use pump up to 10% gas and the oldest is a model year 2000, then a 2003 then a 2011. I use up to 10% gas and honestly I have had zero problems.

 

[JohnnyG]

There is a difference in 2 cycle oils. I have to admit that I'm no expert on the subject, but I did read somewhere on this forum that TCW-3 is for water cooled engines. I'm assuming that air cooled engines require an oil that can stand much higher temps without gumming up the rings.
Had this happen on an air cooled leaf blower once myself. I used "just any" oil and it stuck the rings SOLID! After a while of running poorly (but usable) there was a complete loss of compression, so yeah, very hard to start, stalling, no power, etc.
I still mix my own stuff, but I use the manufacturers oil in the proper proportions.

 

[mk378]

Oil doesn't vaporize or burn like gasoline, so too much oil in the mix makes it act like lean on gas.

If you're using a proper mix you may just need to tune the carb some. Does it rev up OK but die at idle, or does it not run fast well either?

 

[ragtoplvr]

No ethanol does not sell well, as it ages it loses vapor pressure. Can make an engine cold natured. If you mess run it for a few minutes, the crankcase gets hot and it runs well. The sealed in a can does not lose vapor pressure nearly as fast, and it is higher to begin with.

They have vapor pressure lower on pump gas for emissions. Winter gas is highe vapor pressure. .

 

[Chester11]

So it runs at full throttle for about 30 sec and then starts to stumble and stall. If you let off it idles, but stumbles a bit as throttle is added.

The oil fuel mix is right - a premeasured 2.6oz bottle added to a gallon of fuel (50:1). (It's not marine 2 stroke, just some cheap stuff).

I'll have to look at the carb - I'm not even sure if the screws are exposed. I'm guessing counter clockwise turn on the high screw adds fuel?

I have watched a couple carb adjustment videos, but I can't hear when they try to explain adjusting the high side with the machine at full throttle.

 

[Kamele0N]

Whatever you will do with H screw...

If 2 stroke engine sounds like a electric coffe grinder @WOT....you are on the lean side and will sieze its engine...

What you want is to set H screw so that 2stroke engine sounds slightly like it would be 4stroke @WOT...

 

[RyanY]

Hey folks:

To save a few bucks over premix, I mixed up some fresh non-ethanol gas and plain jane 2 cycle oil (I think it was Car Quest or something I picked up at Advance). After running about a 1/4 of a gallon, my 5 year old blower (Hitachi) is now stalling - if you choke it a bit it seemed to run better. It sounded fuel starved, but here is the weird part - I added a few ounces of pre-mix and it runs fine.

My mix runs fine in my other blower - so now I'm really confused. I always thought 2 cycle oil was 2 cycle oil. And I would think if the fuel / oil was bad - the problem would happen in both.

Where do I start? Buy an electric? Is one just more sensitive to octane? (We only have 90 octane non-ethanol here, the premix is 94 I think).

Hitachi only requires 89 octane (10% EtOH is fine) so either of the options you listed are fine. In fact I sometimes use 87 with 10% EtOH if that's all I have on hand when I need it, and really haven't had any problems with it.

The issue you describe sounds like a slightly dirty carb. Not sure why premix would work, but IMO it would be worth cleaning the carb. The easy way is to drain the tank and replace with about 4 oz 50/50 mix of fuel mix and your favorite fuel system cleaner (I have used seafoam, techron, etc all with the same results). Run till it smokes, shut it off, and let it sit overnight. Then fill with fuel mix and run as normal. The better way would be to disassemble and clean the carb properly, if that is possible on the Hitachi (mine has responded well to the soak treatment for the past 8 years so I never tried to do a manual clean).

 

[Chester11]

hahaha...well, bad news. there are no adjustment screws. For giggles I looked at replacement carbs - $84!! (I'm pretty sure I paid about $100 for this new). No knockoff ebay version I could find either.

what the....!!!

So, I'm off to cleaning.

 

[tmorris1]

Check the gas cap vent?

 

[Chester11]

so the air filter was a bit junked with oil. I cleaned it up a bit and it seems to run pretty well.

there might a small leak at fuel tank grommet or just a sticky mess. I pretty much use this thing and then toss it in the shed.

dunno what the issue was - it seems to run ok now. see what happens next year I guess.

if I decide to replace the fuel lines, can I just use anything, or do I have to buy a specific part?

 

[ctechbob]

Don't forget to check the screen(Spark arrestor) in the exhaust as well(If it has one). They can plug up over time and cause issues that you'd swear are carb related.

 

[Kamele0N]

if I decide to replace the fuel lines, can I just use anything, or do I have to buy a specific part?

It depends....if those fuel lines are of basic shape....then you can buy anything...just pay attention that diameter is the same...and that it is made of a fuel resistant material...

OPE shops sell those universal fuel lines...

 

[ironman_gq]

TCW-3 is made for water cooled engines that operate at a much lower temp than an air cooled engine. You will eventually have issues using it in a blower. You should be using an oil made for air cooled engines, better oils leave less deposits and you'll have less issues with carbon plugged rings and plugged exhaust screens

 

[Kamele0N]

Yes.... Jaso FC/FD oils are for air cooled stuff

 

[scrowley]

Red armor is sold at Home Depot.Burns very well at 40:1 for me, with non ethanol.

 

[RyanY]

It depends....if those fuel lines are of basic shape....then you can buy anything...just pay attention that diameter is the same...and that it is made of a fuel resistant material...

OPE shops sell those universal fuel lines...

As @Kamele0N said you can use basic fuel line with the Hitachi. I replaced mine at about 2 y.o. with bulk line from Lowes.

Edit: I forgot to mention that the fuel line grommet usually degrades as fast as the line so this should also be replaced.

 

[jkingrph]

Hey folks:

To save a few bucks over premix, I mixed up some fresh non-ethanol gas and plain jane 2 cycle oil (I think it was Car Quest or something I picked up at Advance). After running about a 1/4 of a gallon, my 5 year old blower (Hitachi) is now stalling - if you choke it a bit it seemed to run better. It sounded fuel starved, but here is the weird part - I added a few ounces of pre-mix and it runs fine.

My mix runs fine in my other blower - so now I'm really confused. I always thought 2 cycle oil was 2 cycle oil. And I would think if the fuel / oil was bad - the problem would happen in both.

Where do I start? Buy an electric? Is one just more sensitive to octane? (We only have 90 octane non-ethanol here, the premix is 94 I think).

From what I have seen you save quite a bit by mixing your own vs premix. I will only use ethanol free gas for my small equipment , large lawn mower and generator, and until very recently the only place nearby that had ethanol free was a small country store/small engine repair shop about 15-18 miles away. Wal mart just put in ethanol free pumps, but there listed octane is a bit lower, so I will probably continue with my country store besides the folks there are nice. I use the Stihl ultra, full synthetic oil and have among my small equipment a Stihl chainsaw that I purchased in 1985 and a large string trimmer that are still going strong, never having to have had service, other than an occasional spark plug change. I do store quite a bit of gas, in anticipation of the occasional power outage, generally giving it a double dose of Stabil, and the oil not for two cycle engines, gets a dose of outboard motor oil at ration of 250/1, figuring a little oil remining in a carb after being run dry and in my steel gas tank will help prevent rust and or corrosion, Been working good doing that for about 18 years now.

 

[Chester11]

Thanks folks!