Why the 25:1 fuel - oil ratio for our engines?

[Polar_Bus]

Im at 25:1 and your at 28:1 how is that tuning related Z

the more oil that is suspended within the fuel , the slower the mixture passes through the carb jets and more fuel volume needs to be added to compensate. Basically richer premix = richer jetting , and adversely leaner premix = leaner jetting

Suck a mouthful of applesauce through a straw (25:1) , then suck a mouthful of just water through the same straw (28:1) and let us know which fluid you were able to suck faster....

 

[Troopermaniac]

I opt for 0:1

 

[21bangbang]

I went leaner on the 5t and am just running the VP 40/1 premix. The little bottles are only $7 and I get 2 tanks. Its nice not having to drag a big can around on top of everything else. We shall see how the engine fares after saun gets it and tears it open. Seems to really run well for what thats worth. Honestly ive never really had running issues though and I credit that to ethonal free fuel. Im convinced thats the cause of a lot of running issues.

 

[Seandonato73]

I went leaner on the 5t and am just running the VP 40/1 premix. The little bottles are only $7 and I get 2 tanks. Its nice not having to drag a big can around on top of everything else. We shall see how the engine fares after saun gets it and tears it open. Seems to really run well for what thats worth. Honestly ive never really had running issues though and I credit that to ethonal free fuel. Im convinced thats the cause of a lot of running issues.

Shell rip when I'm done with it. the ethonal is more fuel system issues, but tbh fuel related issues are most of the issues we see, so happy plumbing happy engine

 

[Freelander]

As pointed out in this thread which I am reviving against all the mental warning not to do so but I found it because I am new. Zenoah G320, amsoil dominator(?) Think it is a synthetic(?) Anyways. Doing the whole manufacturer suggested 25:1 because more oil can't hurt amirite? From the looks of it we don't need to be so cautious. Lots of black stuff on the muffler thing and smoke from the exhaust. Can prolly cut back on the oil it seems.

 

[Rep732]

Put a tuned pipe on it and you'll see the sludge stop. The stock muffler is restrictive and it pools the oil in it, mine did the same thing on my first 5t 2.0. Also have you leaned the needles out some?

 

[Freelander]

Put a tuned pipe on it and you'll see the sludge stop. The stock muffler is restrictive and it pools the oil in it, mine did the same thing on my first 5t 2.0. Also have you leaned the needles out some?

Ok. Thanks. I plan on ordering a pipe and maybe a copper gasket which seems like a good idea when the bank account has a little headroom but no we haven't monkeyed with the needles mostly because we haven't the first clue what we are doing and figured it might be best to keep the factory settings for 1 or 2 tanks of fuel?

The muffler fell off about a week ago and while it was off we noticed the engine idled super high (to the point it was turning the wheels) what is actually going on there? The exhaust or muffler makes back pressure I guess and changes the fuel/air mixture somehow? So changing to a pipe we will have to learn how to adjust these settings on the carburetor?

Just on a very basic level turning the screw clockwise would be less fuel(?) or leaner/more explosive(?)

You can see why not knowing the first thing about small engines we weren't brave or stupid enough to try and adjust these yet.

 

[Seandonato73]

The engine rune changes with many things. The factory can exhaust isn't really restricted in of its self, it doesn't have the benefits of a tuned exhaust. Air temp, air filter ect will also affect state of tune.
The factory needle settings are a "it should run" setting. As the ring wears in the tune will change and need adjusted. You'll quickly get to the point where the tune will be pretty consistent unless there's a large temp swing. Small adjustments are best.

 

[Freelander]

I'll look for a tuning for dummies article and come back when I have a basic understanding and ask questions more directly related to the hobby here. Thank you.

 

[evssv]

i am runnig 28:1 in all my 4...........and i've jus mixed up my last 5ltr of a747 oil in a 28:1 mix...