REFLECTOR:Rough Rider
Scott Derrick
reflector@tvbf.org
Sat, 19 Jul 2003 20:04:48 -0600
Spider is on top and I'm using updraft cooling. I thought about putting
a piece of insulation in the bottom side of the spider to keep it
cooler. Think it would help?
Scott
Mike Pollock wrote:
> Is your fuel injector spider on the top of the engine? Are you using
> updraft or downdraft configuration?
>
> Michael Pollock
>
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Chuck Jensen
> Sent: Saturday, July 19, 2003 11:26 AM
> To: 'reflector@tvbf.org'
> Subject: RE: REFLECTOR:Rough Rider
>
>
> Well, maybe the booster pump is enough to overcome the vaporization in the
> injection line because it will run pretty smooth even down to 700 rpm after
> flight, if the booster is run. But won't smoothly at 1100 rpm wo/booster.
>
> I can see how the temp/conditions in the injection lines would be pretty
> consistent after power operations so the booster pump would have the same
> salutory effect after pretty much any flight.
>
> Good thought on not increasing the idle speed. The brakes already have
> enough work to do without having to overcome a fast idling engine pushing it
> down the runway on landing.
>
> My concern that "this ain't right" grew out of comments from a couple
> mechanics and a CFI that thought smooth engine ops, even at low rpms, should
> not be dependent on the booster pump.
>
> Nonetheless, Scott gets the Southern Comfort(ing)Award, even though I still
> have a tiny bit of residual doubt.
>
> Chuck XL/RG
>
>
>
>
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Scott Derrick
> Sent: Saturday, July 19, 2003 10:54 AM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR:Rough Rider
>
>
> Sounds pretty normal for an injected lycoming.
>
> I have a IO360 which isn't the same engine but the injection system is
> very similar. I also have a Mag/IE combo. My plane runs exactly the
> same. Very smooth idle when cold, idles rough as a cob when hot unless
> I increase the fuel flow to about 5 gph. I can do this using the
> electric fuel pump or just idle it at 1000 rpm instead of the normal
> 600-700 which is what I do when hot. DO NOT increase your idle speed!!
> Bad idea. You want that low idle speed when landing so you can slow down.
>
> This rough idle is worse in the summer for my plane. Its just the fuel
> vaporizing in the injection lines, no biggie as it only happens at low idle.
>
> First time it happened to me I ran to my friend an A&P/IA. He said, no
> problemo. Just Lycomings injection system design.
>
> Your fuel pressures sound right on to me, I think the other pressures
> you are referring to were for a Franklin.
>
> The A&P that enrichened the idle mixture was probably right in doing so
> but that won't effect the vaporization of fuel in your injection lines
> when the cylinders are hot.
>
> Sounds like your setup is right on, keep flying!
>
> Scott
>
>
> Chuck Jensen wrote:
>
>>I have an engine issue that two mechanics have looked at...and that's all
>>they've done. I wondered if anyone has ideas on avenues of
>>investigation/solution. I'm running a 540 with mag/EI combo. The engine,
>>particularly after a long flight (less so after starting cold), runs rough
>>at ramp speed (1,000 rpm). Here are the symptoms with a hot engine after
>>flight:
>>
>>As long as the booster pump is on, runs smooth as glass. VM-100 indicates
>>30 psi (from another post, is that way too high??) and approx. 4.0 gph
>
> @1000
>
>>rpm. If the booster pump is secured, fuel pressure drops to 28 psi, fuel
>>flow shows 1.7 and engine bounces between 650-700 and just barely stays
>>running. Turn the boost back on, and it immediately goes back to smooth
>>operations with the first set of values. Turn the boost off, and it's
>
> right
>
>>back in the dumps.
>>
>>At cruise or high power operations, the boost pump on/off makes no
>>difference in fuel pressure, fuel flow or smoothness of operations.
>>
>>One mechanic suggested that the idle speed needed to be increased. ??
>>Seems he was missing the point. I'm intentionally setting it at 1,000 rpm
>>with the booster, then engine goes in the toilet when the booster is cut.
>>
>>The second mechanic increased the richness setting which may have been too
>>lean since I did not get a temporary rpm increase when cutting off the
>>mixture, but the reliance on the booster pump did not change for smooth
>
> ramp
>
>>operations (especially when hot).
>>
>>Induction plenum has been checked thoroughly but that would seem to be
>>unrelated to the observed symptoms.
>>
>>Questions: 1) are my fuel pressure values way out of line (earlier post
>>talked about 5-6 psi)? 2) if my numbers are bogus, do I
>>have a bad fuel pressure sensor or ground?
>> 3) what do others run for fuel pressure/flow at 1,000 rpm on
>>a 540?
>> 4) is the main fuel pump going in the crapper? (its been
>>this way for a long time with no further
>>degradation/change)
>> 5) is this type of poor low power performance characteristic
>>of deterioration of the positive displacement type
>>fuel pump?
>> 6) is there a way to check the main fuel pump performance?
>>
>>I was in the camp that the main fuel pump is going downhill but I don't
>>understand why, if it is putting out that much pressure, why the fuel flow
>>should fall so much when the booster pump is secured.
>>
>>By all rights, these questions should be investigated and fixed by a good
>>mechanic (which exempts me), but since that avenue has been unproductive,
>
> I
>
>>thought I'd check out the collective wisdom/experience of the
>
> Reflectorites.
>
>>Best idea wins an official Atta Boy award; redeemable wherever good ideas
>>are sold.
>>
>>chuck
>>N27GV
>>
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