[rebel-builders] Engine Running Rough

Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Sun Feb 19, 2012 11:42 am

Running car gas or 100LL ?

I'd suspect a slightly fouled lower plug before going chasing anything else.
With 30 hours and if you haven't been leaning religiously..it's time to
rotate the plugs in each cylinder with a good plug cleaning while you do.
Also check each lower plug for signs of oil as you go. May have one cylinder
with ring blow by or valve guide clearance that's letting oil into the lower
plug/cylinder during shut down.

Wayne

----- Original Message -----
From: "Alvin and Glenys Adams" <gander.electrical@nf.sympatico.ca>
To: "rebel" <rebel-builders-d@dcsol.com>
Sent: Sunday, February 11, 2007 7:29 PM
Subject: [rebel-builders] Engine Running Rough

Doing a few snags after putting 30 hrs on R776.My 0-320 160 hp is
really rough for 2 or 3 seconds when starting.The 0-320 150 hp in my
friends PA-12 is smooth running as soon as it starts.Are all the 160 hp
rough on startup.I have priming lines on only two cylinders,would this
cause the engine to be rough on startup.Do all you guys
prime four cylinders.

Regards: alvin

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Bob Patterson · Post by **Bob Patterson** » Sun Feb 19, 2012 11:42 am

Hi Alvin !

If it smoothes out in a few seconds - it's likely just a bit
over-primed. Try one less pump - and pump the throttle instead ...

The 160s are generally a bit rougher, especially at idle.

--
......bobp
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com

-------------------------------orig.-------------------------
On Monday 12 February 2007 00:29, Alvin and Glenys Adams wrote:

Doing a few snags after putting 30 hrs on R776.My 0-320 160 hp is really

rough for 2 or 3 seconds when starting.The 0-320 150 hp in my friends PA-12
is smooth running as soon as it starts.Are all the 160 hp rough on startup.I
have priming lines on only two cylinders,would this cause the engine to be
rough on startup.Do all you guys

prime four cylinders.

Regards: alvin

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steve whitenect · Post by **steve whitenect** » Sun Feb 19, 2012 11:42 am

I just ran into some plug problems recently at 60 hrs. Hadn't flown sence
last October. Two bottom plugs on the left/impulse mag were bridged with a
bit of carbon. She ran rough and the mag drop was extremely rough and of
course beyond 150 rpm. Cleaned and rotated the plugs and is now normal.
Alvin, if your having normal mag checks after she's warm, then maybe the two
primed cylinders are insufficient for good start or as Bob stated,
overpriming the two to start four. If it smoothens out after 5-10 seconds
but ur not happy with the initial start, then I would get my manifold
information from another port and prime the four.

Steve W. 637R

From: "Wayne G. O'Shea" <oifa@irishfield.on.ca>
Reply-To: <rebel-builders@dcsol.com>
To: <rebel-builders@dcsol.com>
Subject: Re: [rebel-builders] Engine Running Rough
Date: Sun, 11 Feb 2007 19:54:05 -0500

Running car gas or 100LL ?

I'd suspect a slightly fouled lower plug before going chasing anything
else.
With 30 hours and if you haven't been leaning religiously..it's time to
rotate the plugs in each cylinder with a good plug cleaning while you do.
Also check each lower plug for signs of oil as you go. May have one
cylinder
with ring blow by or valve guide clearance that's letting oil into the
lower
plug/cylinder during shut down.

Wayne

----- Original Message -----
From: "Alvin and Glenys Adams" <gander.electrical@nf.sympatico.ca>
To: "rebel" <rebel-builders-d@dcsol.com>
Sent: Sunday, February 11, 2007 7:29 PM
Subject: [rebel-builders] Engine Running Rough

Doing a few snags after putting 30 hrs on R776.My 0-320 160 hp is
really rough for 2 or 3 seconds when starting.The 0-320 150 hp in my
friends PA-12 is smooth running as soon as it starts.Are all the 160 hp
rough on startup.I have priming lines on only two cylinders,would this
cause the engine to be rough on startup.Do all you guys
prime four cylinders.

Regards: alvin

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Jthomasusa1 · Post by **Jthomasusa1** » Sun Feb 19, 2012 11:43 am

Alvin:

Thanks for sharing your primer info. One start of mine just poured fuel out
bottom of cowl.

I'm checking my injectors first thing.

All the Best,

John in NC
N83MR

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Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Sun Feb 19, 2012 11:43 am

That sounds more like a stuck float/needle valve in the carb...or you were
pumping the throttle while cranking. Remember it's an updraft carb. If it
doesn't start that fuel you pumped in ..gravity takes over.

As for the primers. Yes there is a spray tube on the lyco certified
fittings. I have a few here..but that said my own engine just has normal
1/8" NPT compression fittings and things start/run just fine. A pump or two
on the primer is a pump or two on the primer, volume wise of fuel....no
matter what the fuel comes out of at the other end. To help get it spread
FAST strokes on the primer so it comes out and splatters around in the
cylinder.

----- Original Message -----
From: <Jthomasusa1@wmconnect.com>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, February 14, 2007 9:23 AM
Subject: Re: [rebel-builders] Engine running rough

Alvin:

Thanks for sharing your primer info. One start of mine just poured fuel
out
bottom of cowl.

I'm checking my injectors first thing.

All the Best,

John in NC
N83MR

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Bob Patterson · Post by **Bob Patterson** » Sun Feb 19, 2012 11:43 am

Or maybe the electric fuel pump was on, and pushing the float needle
down, flooding the carb ....... ! :-)

--
......bobp
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com

-------------------------------orig.-------------------------
On Wednesday 14 February 2007 15:10, Wayne G. O'Shea wrote:

That sounds more like a stuck float/needle valve in the carb...or you were
pumping the throttle while cranking. Remember it's an updraft carb. If it
doesn't start that fuel you pumped in ..gravity takes over.

As for the primers. Yes there is a spray tube on the lyco certified
fittings. I have a few here..but that said my own engine just has normal
1/8" NPT compression fittings and things start/run just fine. A pump or two
on the primer is a pump or two on the primer, volume wise of fuel....no
matter what the fuel comes out of at the other end. To help get it spread
FAST strokes on the primer so it comes out and splatters around in the
cylinder.

----- Original Message -----
From: <Jthomasusa1@wmconnect.com>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, February 14, 2007 9:23 AM
Subject: Re: [rebel-builders] Engine running rough

Alvin:

Thanks for sharing your primer info. One start of mine just poured fuel
out
bottom of cowl.

I'm checking my injectors first thing.

All the Best,

John in NC
N83MR

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Jthomasusa1 · Post by **Jthomasusa1** » Sun Feb 19, 2012 11:43 am

Wayne:

You know, I think I will get out the Lycoming Opns Manual and start "by the
book". I may be guilty of using bad procedures. Just may save me some extra
work.

Thanks,

John in NC

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Jthomasusa1 · Post by **Jthomasusa1** » Sun Feb 19, 2012 11:43 am

Hi Bob:

Another good point. Will check that out. Since I know gravity feed OK while
running, Guess I may not need for start also.

Owe you a picture of bottom cowl. WILCO soonest.

With throttle adjustment, I now have 2250 with the 58 prop. Meets Bingelis's
FWF guidance. Will flight test this week.We have major winds here in the
Carolinas now.

Trust all is well.

John in NC

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