smartcarb

[skippydiesel]

15 minutes ago, turboplanner said:

A.       In-an-engine-we-are-assessing-less-fuel=less-power.

B.       On another engine, say a "modern injected 2 stroke outboard" with its fraction of fuel - if it's given less fuel there will be less             power.

 

I thought this discussion was about a particular fuel metering system/carburettor ("Smartcarb")  - not a specific engine.

 

Seems you are off on a tangent , as is your habit.😈

[BrendAn]

2 hours ago, Thruster88 said:

6200 static and 6500 on climb. Full throttle level flight is just under the max of 6800. 

My 618 is pretty close to that. 

Just under 7000 rpm flat out on climb. I have been thinking of giving it a bit more pitch.  So I get around 6600 on climb and bring cruise back to around 5800.  Egt around 600 now. 

[BrendAn]

17 minutes ago, skippydiesel said:

I thought this discussion was about a particular fuel metering system/carburettor ("Smartcarb")  - not a specific engine.

 

Seems you are off on a tangent , as is your habit.😈

He was quoting what I said.

Read the earlier posts

[facthunter]

Yes I wouldn't suggest over  revving that Motor. Nev

[skippydiesel]

"Oil Injection vs Premix:
• On premix engines, any change in fuel flow directly changes the oil ratio."

 

How is this statement correct ??

 

Never been a 2/ fan however my understanding of premix is that;

• The oil & fuel is added/ premixed at a certain ratio eg 50:1 in my chain saws. 
• The mixture is then put in the fuel tank.
• The fuel mix is then metered through the carburettor to the combustion chamber, where it is burnt.

 

During the above process there is no opportunity to change the fuel oil mix ratio - in my example it remains at 50:1, no matter how I tune the carburettor (rich or lean)

😈

[skippydiesel]

2 minutes ago, BrendAn said:

He was quoting what I said.

Read the earlier posts

My apologies - I understood the thrust of your questions to be; how does a claimed 30% reduction in 2/fuel ("Smartcarb")  effect the lubrication of the engine, specifically where premixed fuel is used.

 

The engine/carburettors you mentioned I took to be illustrative ie not part of the origional question.😈

[BrendAn]

6 minutes ago, facthunter said:

Yes I wouldn't suggest over  revving that Motor. Nev

The book says 7000ax on climb out so it has been setup pretty well but I would like to pull it back a bit as long as egt stay within range.

[facthunter]

I mentioned earlier that adding oil to fuel increases It's viscosity which makes it flow slower thus Leaning the Mixture/ THAT statement is NOT CORRECT as you point out.. I would suggest that they MEANT Oil  Available to the engine. Way Back a Friend of mine riding a Bultaco at Mt Panorama put a foot operated oil pump on his  bike to Prevent  engine damage down conrod straight. A chain saw should require LOAD to make it fire evenly and it should be rich enough to never scream and do high revs. Nev

[facthunter]

BrenDAn,  The MOTOR YOU Have had a reputation for breaking Crankshafts near the  drive end.  Nev

[BrendAn]

6 minutes ago, facthunter said:

I mentioned earlier that adding oil to fuel increases It's viscosity which makes it flow slower thus Leaning the Mixture/ THAT statement is NOT CORRECT as you point out.. I would suggest that they MEANT Oil  Available to the engine. Way Back a Friend of mine riding a Bultaco at Mt Panorama put a foot operated oil pump on his  bike to Prevent  engine damage down conrod straight. A chain saw should require LOAD to make it fire evenly and it should be rich enough to never scream and do high revs. Nev

This is why I started the thread. Trying to understand how they use 30 percent less fuel without leaning the engine out too much. 

Oil injection should be ok when oil is injected after the carby.

[BrendAn]

6 minutes ago, facthunter said:

BrenDAn,  The MOTOR YOU Have had a reputation for breaking Crankshafts near the  drive end.  Nev

Pretty rare I think.  Rotax rick reckons they were the best of the Rotax 2 smokes. Detuned from 135 HP in the snow mobile version.

I have spoken to a few people that have never had an issue.

I think if they are looked after and operated by the book should be good like most engines.

 

[BrendAn]

31 minutes ago, facthunter said:

BrenDAn,  The MOTOR YOU Have had a reputation for breaking Crankshafts near the  drive end.  Nev

A couple of paragraphs off a gyro forum. Shows all models can break cranks. Gyros are pretty hard on 2 strokes. Driven flat out all the time.

[facthunter]

The original Book may not be the Best reference, Currently. Nev

[Thruster88]

44 minutes ago, BrendAn said:

The book says 7000ax on climb out so it has been setup pretty well but I would like to pull it back a bit as long as egt stay within range.

The 618 needs those revs to make use of the temporarily raised exhaust ports to make the extra power. In a motorbike those valves would get plenty of action, in an aircraft not so much which may lead to sticking. 

[facthunter]

 There's a Lot of ways of helping them Last Better. Gyros need Lots of Power. Carbon Behind the rings is a Killer.  Big end Cages fail and the Hard skin flakes off the Crank Pins and the results of that are Quick and fast.  Any Holey Piston Means aluminium all through that Cylinder and case. Nev

[BrendAn]

1 minute ago, Thruster88 said:

The 618 needs those revs to make use of the temporarily raised exhaust ports to make the extra power. In a motorbike those valves would get plenty of action, in an aircraft not so much which may lead to sticking. 

True,  some people in high altitude regions run cables to operate them manually.  I flick the plastic covers off occasionally and work them by hand .  Although running amsoil full synthetic should stop carbon build up.