What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV6A starting difficulty

glen25781

glen25781

Member
Hey guys and gals,

Pulled my awesome little bird out of the hangar this morning (6A with an O-320 Lycoming) and it wouldn't start. Prop turned over just fine ... the battery is only a few weeks old and cranking is strong but it just wouldn't fire..not even one little sputter. Outside temp here was colder than usual here in the Florida panhandle - 45 degrees - but I don't really think the temp was an issue.

I usually give the throttle a couple of pumps before I start it and then keep the throttle open about 1/2 inch with the mixture rich and it always fires right up easy as pie...until this morning. Ended up and cranking and cranking to no avail. Called my A&P and he said I may have flooded it so try this: a hot start procedure where you pull the mixture full lean, open throttle about halfway open while holding the brakes and try again til it fires, then quickly full rich.
I Tried that several times, then gave up and decided to let it rest overnight, throw the trickle charger on the battery and try again tomorrow.

Any ideas?

Thanks in advance,

Glen
 
Won't start....or even pop.....

glen25781 said:
Pulled my awesome little bird wouldn't start. Prop turned over just fine ..but it just wouldn't fire..not even one little sputter.
I usually give the throttle a couple of pumps before I start it and then keep the throttle open about 1/2 inch with the mixture rich and it always fires right up easy as pie...until this morning. Ended up and cranking and cranking to no avail. Called my A&P and he said I may have flooded it so try this: a hot start procedure where you pull the mixture full lean, open throttle about halfway open while holding the brakes and try again til it fires, then quickly full rich.
Click to expand...

Well, there is always the IT question: is it plugged in? Or in this case: was the fuel turned on? I know: silly question but I could tell you stories. I would also imagine you have started it the same way without problems for quite a few hours of flight. I agree: temperature probably was not a factor.

I might agree with your A&P. Could have been flooded. We tend to 'just pump it a little more' when it isn't firing. The old solution is to turn the prop backwards. Easier to do with a C-90 Cub but it works. How many blades? Depends on I don't know what. 4 or so usually works. Just make sure the mags are off! Have the key in your pocket when you do this!

OK: carburetor or injection? Primer? Do you pump the throttle while you are cranking or before? Pumping the throttle while you are cranking gives the fuel you are squirting up the carburetor somewhere to go. Otherwise you might see it dripping out of your air filter box. Electronic ignition or magnetos? With a little more information I'm sure other ideas will be forthcoming.....;)
 
If the plane was inside a 65 F hangar and the temperature dropped to 45 F in a short period of time, there would be a risk for condensation.
If you have conventional magnetos I would check for water droplets inside the
distributor.

Good luck
 
I see this all the time in the midwest winters. At 40*, you will need at least 2 times as much prime as you do at 70*. If you are pumping the throttle before hitting the starter, it will NEVER start at those temps. All that fuel just gets dumped into the air filter box. Throttle must be pumped while engine is spinning to get that fuel into the cylinders. May work in the summer, but not at those temps when you need more fuel to get a kick.

In addition to the starting challenges, this is also a fire risk. You dump an ounce or two of raw fuel into the FAB. Heaven forbid you get a backfire, as this will ignite that raw fuel and create an engine fire. I tell everyone I know to NEVER pump the throttle unless the engine is spinning. This applies only to crabs, of course.

Please do not move to this approach with the throttle out half way. Once you start priming correctly, you will no longer need this and will get startled when it jumps to 2000 RPM after kicking. When I had a carb, I only needed three pumps while cranking to get my 320 started at 20*

Larry
 
Last edited:
Glen, do you have a primer? My club's Cherokee will never start without priming - pumping the throttle is a waste of time and fuel and can be dangerous (fire).
 
Last edited:
rv8ch said:
Glen, do you have a primer? My club's Cherokee will never start with priming - pumping the throttle is a waste of time and fuel and can be dangerous (fire).
Click to expand...

This is incorrect, and contrary to what many RV owners with carbureted engines experience.
I assume you meant to say, never start without priming.
There are thousands of RVs with carved engines that have no primer system and they start just fine in cold temperatures. As long as they have a carb with an Excelerator pump and the proper technique is used.

Pump in the throttle should be done briskly. I always reduce the throttle friction. And it should only be done while the engine is cranking. And temps of 30 to 40 Fahrenheit. The engine will usually fire after the third or fourth pump. Obviously, once it fires stop pumping.
 
Most everybody has covered it for you. We see this all the time with carbs once the temps are in the 40’s. A gas has very low vapor pressure at those temps. You have to get the fuel INTO the cylinders. Pumping before cranking does nothing. You have an updraft carb, so pumping prior to cranking squirts the fuel straight up and tight back down into the AirBox. Be thankful you didn’t have a kickback, as that is how AirBox fires start. Two of our customers have lost their airplanes to AirBox fires over the last year.

The problem everyone has right now is muscle memory. You’ve been pumping a squirt or 2 prior to starting all during the warm season, and it worked because the fuel was warm enough to vaporize a little. Now you have to think before you start——- no pumping until cranking, and be ready to reduce the throttle as soon as it fires. Your stick is back and the brakes are locked, right?

It will work. If not, you need to check your intake gaskets, as the only way the fuel gets into the cylinders in a carb’s engine is by the suction effect of the intake stroke. Leaking gaskets will do away with that suction.


An even better way to help with cold starts—— some preheat. I preheat all of mine below 60 degrees F. It spins faster, starts faster, and the oil is circulating faster. Install a sump oil pan heater at your next oil change or CI.

Vic
 
I love the typo's in this thread.... :p

I tell everyone I know to NEVER pump the throttle unless the engine is spinning. This applies only to crabs, of course.

There are thousands of RVs with carved engines that have no primer system and they start just fine in cold temperatures.

Sorry, can't help myself....... I had a job as a proofreader many years ago, at minimum wage......... which at that time was $1.00 per hour! :eek:
 
Last edited:
rvbuilder2002 said:
This is incorrect, and contrary to what many RV owners with carbureted engines experience.
I assume you meant to say, never start without priming.
There are thousands of RVs with carved engines that have no primer system and they start just fine in cold temperatures. As long as they have a carb with an Excelerator pump and the proper technique is used.

Pump in the throttle should be done briskly. I always reduce the throttle friction. And it should only be done while the engine is cranking. And temps of 30 to 40 Fahrenheit. The engine will usually fire after the third or fourth pump. Obviously, once it fires stop pumping.
Click to expand...
Thanks Scott - you are correct - I meant to write "My club's Cherokee will never start without priming "
 
Dyslexic typing......

PCHunt said:
I love the typo's in this thread.... :p
I tell everyone I know to NEVER pump the throttle unless the engine is spinning. This applies only to crabs, of course.
There are thousands of RVs with carved engines that have no primer system and they start just fine in cold temperatures.
Sorry, can't help myself....... I had a job as a proofreader many years ago, at minimum wage......... which at that time was $1.00 per hour! :eek:
Click to expand...

I was trying SO HARD not to say anything!! I had to stop with several of them and repeat them so I could just hear myself say that this only applies to crabs....:D:D:D Mrs Foster (my 7th grade English teacher) can be heard thumping in her grave....:D:D Proofreading: I did that in college! Yea, that was a "pea-picking" job! Everyone has to have a pea-picking job to appreciate moving up!!:p
 
Thanks so much guys!

You guys are truly awesome! So much great advice from guys who are flying these birds regularly..

Yes, it is carbureted with magnetos. I took all this advice today and it started perfectly, then went out and flew for a while with a friend. Today I did one throttle pump as the engine was turning over and it fired right up!

I keep learning every day and love my RV even more...thanks again!
 
PCHunt said:
I love the typo's in this thread.... :p

I tell everyone I know to NEVER pump the throttle unless the engine is spinning. This applies only to crabs, of course.

There are thousands of RVs with carved engines that have no primer system and they start just fine in cold temperatures.

Sorry, can't help myself....... I had a job as a proofreader many years ago, at minimum wage......... which at that time was $1.00 per hour! :eek:
Click to expand...

Roadjunkie1 said:
I was trying SO HARD not to say anything!! I had to stop with several of them and repeat them so I could just hear myself say that this only applies to crabs....:D:D:D Mrs Foster (my 7th grade English teacher) can be heard thumping in her grave....:D:D Proofreading: I did that in college! Yea, that was a "pea-picking" job! Everyone has to have a pea-picking job to appreciate moving up!!:p
Click to expand...

Yea, I get it. Typos and other poorly worded statements or questions sometimes annoy me as well.
I will totally skip posting to someone’s question sometimes because I am not sure what they are asking.
But I also try and be gracious.

In this instance, I once again got burned by technology, using voice texting to type on my phone ( something that still leaves a lot to be desired when using it for technical subject matter) and I failed to proof read it well enough.

If these forums become a place where people are hesitant to post for any reason, it would be a shame, because of all of the great content that would never happen because of it.
 
rvbuilder2002 said:
Yea, I get it. Typos and other poorly worded statements or questions sometimes annoy me as well.
I will totally skip posting to someone’s question sometimes because I am not sure what they are asking.
But I also try and be gracious.

In this instance, I once again got burned by technology, using voice texting to type on my phone ( something that still leaves a lot to be desired when using it for technical subject matter) and I failed to proof read it well enough.

If these forums become a place where people are hesitant to post for any reason, it would be a shame, because of all of the great content that would never happen because of it.
Click to expand...

You need to proof read.....
joke neighbor wife and wifi.JPG
 
rvbuilder2002 said:
Yea, I get it. Typos and other poorly worded statements or questions sometimes annoy me as well.
I will totally skip posting to someone’s question sometimes because I am not sure what they are asking.
But I also try and be gracious.

In this instance, I once again got burned by technology, using voice texting to type on my phone ( something that still leaves a lot to be desired when using it for technical subject matter) and I failed to proof read it well enough.

If these forums become a place where people are hesitant to post for any reason, it would be a shame, because of all of the great content that would never happen because of it.
Click to expand...

There are very few posters on this forum that I appreciate more than you! I hope that you, and others, would realize that my comments were in no way intended to be any kind of "hit". Quite the opposite: I just thought those two typos were particularly funny.

I was only trying to add a bit of humor to this web site. I think it needs a bit of that right now.

There are thousands of typos, misspellings, incorrect words, etc. on this forum every day. I never comment on any of them.

Agin, I just thort they wer funy, so I thort that I wud give everone a bit of a Laff.

:rolleyes:
 
You must log in or register to reply here.
Back
Top