Aeroinjector Issue

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myles-dean

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Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Good afternoon,

I am now into taxiing the Sonerai in preparation for flight.
During the rebuild, I took off the original POSA carb and installed a never used Aeroinjector.
The engine will idle smoothly but will sputter/fluctuate in RPM & consistently stall in between the range of 1700-2100.
Once above the 2100, it runs great and produces good power.
The static RPM is 3100.
Mixture has been set rich.

I have a K&N air filter installed and will hopefully running it this weekend (however the wxx looks like rain until Tuesday) without to see if there is any change.

Any suggestions as to why it's running like a bag of hammers in the 1700-2100 range?
 

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Flyguyeddy

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Jun 9, 2018
Messages
143
Location
Central illinois
What is going on with those aluminum things on the bottom of your heads?

You have an aerocarb, not an aeroinjector. Perhaps problems with the needle? I believe they are brass on the older models.
 

eschrom

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Jan 18, 2006
Messages
760
Location
Harrisburg, PA
Don't know whether this is your problem but it's been said that the Aerocarb works best when the needle lies in the same vertical plane as the crankshaft - better fuel distribution left-right. Are you using the no. 2 needle?

Just curious, what's the function of the Liquid Wrench can?

Ed
GP 2276 with AeroCarb
 

Soneraifred

N99FK and me at OSH
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Jan 12, 2006
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Location
Franksville, WI
Have you tried exercising the mixture control in the 1700 - 2100 rpm range to see if the engine is running too rich?
 

myles-dean

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Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
The aluminum cowls are cooling trays.
The original owner had them installed, not sure if there was any benefit to them.

You are correct on the Aerocarb, my mistake.
I double-checked tonight and they are brass needles.


Flyguyeddy said:
What is going on with those aluminum things on the bottom of your heads?

You have an aerocarb, not an aeroinjector. Perhaps problems with the needle? I believe they are brass on the older models.
 

myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Thank you for pointing that out, I will be changing to flexible this weekend.
Not sure why I didn't catch that earlier, I appreciate the feedback.

Kevin R. said:
That copper line between the gascolator and the carb needs to be a flexible line. It will work harden shortly as the engine moves independently of the airframe and break.

Kevin
 

myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
I'm not sure how to get the carb/needle into the same vertical plane as the crankshaft.
There just isn't enough room in the cowling to move things around.

I pulled the needle and verified that no. 2 needle is installed.
It is bottomed out, so maybe I need to richen the mixture by turning the needle out.
When I pulled it, I did notice that the flat was 90 degrees from the engine; saw in the manual that the flat should face the engine.
I reinserted the needle with flat facing up. Maybe get to run the engine on Sunday to see if that fixed the issue.
Am planning on making one change at a time, hoping to be able to determine what the fix is.

As for the Liquid Wrench can, I am using that as a small residue oil reservoir.
The original owner had made up an oil separator for the blowby hose.
I've attached a photo of the separator, not sure if it will work but looks like it might.
My thought is that the separator will retain some of the oil that will normally blow out, then settle into Liquid Wrench can once the engine is shut down.
Will see!

eschrom said:
Don't know whether this is your problem but it's been said that the Aerocarb works best when the needle lies in the same vertical plane as the crankshaft - better fuel distribution left-right. Are you using the no. 2 needle?

Just curious, what's the function of the Liquid Wrench can?

Ed
GP 2276 with AeroCarb
 

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myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
I have tried to lean out in that range but it seems to cause it to stall.
I am thinking that it may be lean in that range, however it doesn't make much sense to me my there is a lot of power beyond 2100.
It doesn't miss a beat at full throttle and can handle RPM changes both smooth and prompt (above the 2100 range).

After verifying the needle flat in reference to the engine, I will try adjusting the needle mixture a bit.


Soneraifred said:
Have you tried exercising the mixture control in the 1700 - 2100 rpm range to see if the engine is running too rich?
 

Flyguyeddy

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Jun 9, 2018
Messages
143
Location
Central illinois
Someone used the newer aerovee 2.1 with aerocarb on their sonerai. You could search for the pictures on the aerovonversions website, they have the carb arranged in a longitudinal setup
 

eschrom

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Jan 18, 2006
Messages
760
Location
Harrisburg, PA
Needle bottomed out and flat turned the wrong way may be the causes. Let us know how you make out.

Orienting the AC longitudinally was a tight squeeze but I was able to do it and the performance is good. But I never tried it laterally so I can't compare.

Ed
 

myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Hi Tim,

Thanks for the photo and verification that the carb does work ok in that orientation.
I have been running and taxiing the plane with the cowlings on.

It's been raining here off and on since Friday, so haven't been able to do any test runs.

Will post once I can get it fired up again.

Thanks for the help.

Pttim said:
Mine was mounted as your is and also filtered. I did not run well with the cowling off. Try cowling the engine.
 

mhflyit

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Joined
Jun 2, 2012
Messages
818
Location
Jupiter, FL
Coupla ideas:

The fuel line should run slightly 'uphill' to the carb...try that when you change to a flexible hose. Mine is also oriented like Tim's...fuel intake at the top.

Could your carb heat be affecting the fuel/air mixture at that RPM range?...The aeroinjector doesn't 'need' carb heat with the intake design being resistant to ice.
 

myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Hi,

I still have to make up the flexible fuel line and will make the change to being slightly uphill to the carb.
As for the carb heat, I don't believe that it is affecting the fuel air mixture as I have make sure that it is fully shutoff at the diverter box.
If the problem continues, I will definitely try running it without the carb heat attached.... never hurts to try.
Thank you for the ideas!


mhflyit said:
Coupla ideas:

The fuel line should run slightly 'uphill' to the carb...try that when you change to a flexible hose. Mine is also oriented like Tim's...fuel intake at the top.

Could your carb heat be affecting the fuel/air mixture at that RPM range?...The aeroinjector doesn't 'need' carb heat with the intake design being resistant to ice.
 

myles-dean

Well-Known Member
Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Good morning everyone,

Wanted to post an update on the AeroCarb; this was the information I sent to Aeroconversions when requesting troubleshooting help.


I have an old style AeroCarb with the throttle and mixture cables threaded through the body; no idle set screw.
It was never used by the previous owner.
Using brass needles and needle seat/orifice is plastic in the body.
There is free movement with the cables and no binding on either.
Mixture is set correctly with no fuel bypassing when in full lean.
Engine has been run numerous times but am unable to get a smooth transition between idle to WOT.
Runs really well at WOT and wavers at all other ranges.

It is definitely running rich (after pulling a plug to inspect) and initially had the #2 needle installed.
Could not lean out enough by adjusting the needle only, always had to pull mixture out about an inch to inch and a half to lean.
Changed to the #1 needle and made sure the needle was orientated correct, marked taper and set depth correctly, etc.
Found that once again it is running very rich, had to use the mixture again to lean out (still an inch to an inch and a half).

Throttle always has free movement when shut off and while engine is running.
After awhile, the throttle started binding which seemed really strange because as soon as the engine was shut off, immediately there was no binding again.
After a few times testing, it would bind every time only when the engine is running.
Thinking that maybe it is still too rich, with the engine off and adjuster cap off, I pulled the throttle wide open to access the needle and there was a lot of fuel that shot out at me.
It appears that there is fuel leaking around the slide and it is causing hydrolock in between the backside of the slide and body.
After finding this, I started the engine and once the throttle started binding, turned off the engine and manually moved the throttle at the carb; each time significant fuel shot out of the adjuster access hole.



This is the condition that everything is presently at.
Turns out the delrin plastic seat is not replaceable and Aeroconversions is suggesting that the throttle block is likely causing the binding.

It still doesn't make sense to me that fuel should be getting behind the throttle slide.

Thinking a switch to a Zenith carb may be in order......


Regards,
Myles
 

eschrom

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Joined
Jan 18, 2006
Messages
760
Location
Harrisburg, PA
I've experienced binding exactly the way you describe, even thought once that ice was causing it because it cleared up when the engine was shut off. After making a DIY cable clamp and tinkering with it for a while the problem seems to be solved.

As for mixture, mine's pretty good. Slightly rich at WOT, richer at cruise (pulling out the mixture knob an inch fixes it), and lean at idle (which I like). But the only reason I know all this is the air-fuel gauge. By sound only it runs well without any mixture adjustments.

If yours is rich no matter how you set the needle I wonder if the orifice is too big?

Ed
 

myles-dean

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Joined
Mar 18, 2013
Messages
79
Location
Stonewall, Manitoba, Canada
Hi Ed,

I am going to have a second look at my cabling to see if that is the issue.
Glad you were able to get yours working.

Mine is rich throughout the whole range, no matter which needle is installed.
Definitely a frustrating experience getting this to work!

I am really thinking the orifice is too big but Aeroconversions stated: "It is highly unlikely the delrin fuel orifice is damaged. They cannot be replaced but under normal use they never need to be replaced."


eschrom said:
I've experienced binding exactly the way you describe, even thought once that ice was causing it because it cleared up when the engine was shut off. After making a DIY cable clamp and tinkering with it for a while the problem seems to be solved.

As for mixture, mine's pretty good. Slightly rich at WOT, richer at cruise (pulling out the mixture knob an inch fixes it), and lean at idle (which I like). But the only reason I know all this is the air-fuel gauge. By sound only it runs well without any mixture adjustments.

If yours is rich no matter how you set the needle I wonder if the orifice is too big?

Ed
 
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