Why won't my "1 flip" engines start?

Strange thing happened at the Southwest Regionals last week. Neither of my engines would start. I have an OS20FP in my OTS Super Clown and an OS25FSR in my Primary Force. Both engines had consistantly been 1 flip starters until last weekend. The 20FP would start then run slowly for 5 - 10 seconds and die. When I finally got it started, it ran great as usual. Same prop, plug, and fuel as before. Between flights, I changed plugs and got another battery, but had the same results.

On my 25FSR, it would not fire using the normal starting proceedure and only started after being choked for 8-10 times, then flipped backwards until the flood cleared. Tried several batteries with the same results. Again, once started, it ran normally.

I'm looking for any suggestions to get back to the easy starting without scrapping the engines.

Steve

>
>I'm looking for any suggestions to get back to the easy
>starting without scrapping the engines.
>
>Steve

Steve;

First thing I would ask is what was different from the last time you ran the engines and got one flip starts. Fuel? Location? Weather? Procedure? Also, had it been a while since you had flown and possibly the fuel could have absorbed sufficient moisture to alter start characteristics?

V/r

Bob

>
>>
>>I'm looking for any suggestions to get back to the easy
>>starting without scrapping the engines.
>>
>>Steve
>
>Steve;
>
>First thing I would ask is what was different from the last
>time you ran the engines and got one flip starts. Fuel?
>Location? Weather? Procedure? Also, had it been a while
>since you had flown and possibly the fuel could have absorbed
>sufficient moisture to alter start characteristics?
>
>V/r
>
>Bob
Bob,
That is my concern, there was nothing different that I know of and both engines had been flown within a week of the contest. The temperature might have been a little warmer, but not a big change. I have been using a "standard" proceedure on these engines - choke once or twice (depending on which engine), flip forward 5 times (without the battery) followed by 5 reverse flips, hookup the battery, and usually 1 flip and it is running. It did not work on either engine this weekend. I will try a new can of the same fuel next time I fly.

Steve

That's something that happens to glow engines in cooler and or cold weather. They take a bunch more prime to get running. They also like to be warmed up in cool weather by running the prime out anywhere from 1 to about 4 times. Also use 5% fuel if you have been using 10% during the warmer months, but beware, the engine will run longer so you may have to adjust to prevent over runs.


Jim Pollock

What was the temperature? And how cold was the engine itself? If it sat out overnight it might have been much colder than the air temp. Did it freeze overnight?

If anything the weather was a little warmer. We've been starting our flying around 9:30 this winter to let it warm up a little (at least into the mid '50s) and the high temp on Saturday was in the low 60's so maybe high 50's or low 60's by the time I flew. I usually run 10% nitro year round, although I sometimes use 15% on the 20 during really hot days. The FSR has plenty of grunt on 10%.
Steve

Steve,

I have an idea that the cooler weather is the main culprit. Also, if you are using all castor in your fuel, that combined with the cool weather will sometimes make an engine more troublesome to start. I would suggest to burp the engine just before you fuel and fly. Just put a few drops of fuel in the venturi, turn the prop over several times, use a good strong battery and run the prime out.

When you get to know the engine under the cooler conditions, you will learn what it needs as far as how long it can sit between runs without needing to have a prime run through it befor you fly again. You will also need to determine how much fuel is needed for the prime. It could vary from maybe several drops to a fairly healthy stream of fuel into the venturi.

I have seen top pilots burp their engine before every official flight, even in very warm conditions. This assures that there is not a bunch of fuel puddled somewhere in the engine that could cause difficulties in the starting procedures and it also makes sure that the engine is ready to go. In this cooler Tucson weather this past month, I will burp my engine every time berore a flight if it has sat in the pits for more than an hour.

(edit for typo)

Why is no one reading this guy's posts? He says it was WARMER!

I think maybe there could be a humidity change, or an elevation change that might have done that. The elvation could cause the need for more prime. How far did you travel to this contest, or is it local for you? If the contest was local then I am wrong on that one for sure.

Also once the engine was running you said it ran the same. That is good. Did you have to severly adjust the needle one way or the other to get the initial run once it started, the first time?

>I think maybe there could be a humidity change, or an
>elevation change that might have done that. The elvation
>could cause the need for more prime. How far did you travel
>to this contest, or is it local for you? If the contest was
>local then I am wrong on that one for sure.
>
>Also once the engine was running you said it ran the same.
>That is good. Did you have to severly adjust the needle one
>way or the other to get the initial run once it started, the
>first time?
>
>
Doug,
I'm local Tucson guy, so no change in altitude. On the 20FP, the needle did not change, but on the FSR, the first flight was very lean to the point of the engine sagging in consecutive maneuvers. It needed almost a full turn open on the OS needle valve for the second flight which was right on. Maybe a clue there - filter? Lots of good ideas for things to check here. Thanks for the help.
Steve

>Why is no one reading this guy's posts? He says it was
>WARMER!
>

Hi Doug,

I read his posts. We fly together on Wednesdays, Fridays, Saturdays and Sundays. This past week and at the SW Regionals, it has been in the high 60's and Sunday, it was in the 70's. But it still gets cool at night, like into the 30's. It has even been below freezing a couple of times. If his airplane is in an unheated garage, even overnight from the previous day of flying, coolness can still be the culprit with thickened oil preventing a normal choke, or thickened oil fouling the plug, or thickened oil restricting the flow of fuel in the line, even though the day has warmed up. Even thickened oil restricting fuel through an otherwise clean fuel filter can also be a problem with an ovenight storage in a cooler garage.

Otherwise, thanks for pointing out that we are not reading Steve's posts.

Keith you didnt say anything about it freezing at night or anything like that. I was following along and there were several posts saying cooler weather causes his symptoms. I agree. But then he says it is warmer out. It looked like no one wa reading the entire posts.

Even with it cold at night the engine doesnt stay cold much longer than when the tem warms up and few minutes in the outsdie warm temps and it should be fine. From what I could tell he was having this problem through the day. If it were as you said the cold night causing the issue it would only be in the FIRST run of the day and then none others. It would be interesting while he is having this problem if he were to try someone elses fuel as a test.

Steve, I have had partially blocked fuel filters cause this problem in the past. Smaller filters with very fine screens seem to be more critical. Hope this helps.

I remember an old "Dukes Mixture" Ad by Duke Fox. It had a question and answer format. The question was "My motor won't start on the first flip anymore, what can I do?" Duke's answer "Try two flips."

The new generation of motors all start on the first flick.

Any change in after run oil?

>Any change in after run oil?

Nope, still using Marvel air tool oil.
Steve

>>Any change in after run oil?
>
>Nope, still using Marvel air tool oil.

Hi Steve,
I have had the same problem. I would do the burb thing as it helps clean out the after-run oil. I discovered that the little pocket the the plug coil lives in gets filled with after-run oil and it won't fire. Sometimes it's just fine and sometimes it's not. usually if I wait until I get home from the field and put after-run oil in and flip it a couple times and hang it up the next time I try to fire it up, no problem. But sometimes I put it in when I'm still at the field or if I put too much in, I set the plane down and watch the other flights for awhile. When I get home I hang it up........Too late the oil has already run into the plug (inverted motor). The engine doesn't have to be inverted, a few good flips to many and oil will get it into the plug on a profile also.


Greg L. Bahrman

Steve,

I think you've got all the good ones now, except for this thought:

You said, if I recall, that the engines ran briefly, then quit, at first.

With the OEM OS muffler, I've found that it seems that sluggish fuel supply can cause that, particularly for a first-of-day start. If you're using the OEM can, a tap* on the muffler outlet can goose the tank pressure enough to get through to steady fuel delivery.

*-Just a brief closure of the exhaust hole, not long enough to get hot. Excess closure can flood them off, but a tickle like that is like a needed prime while the engine is running, Learned this from RCers; see, they're not totally useless...

"If you're using the OEM can, a tap* on the muffler outlet can goose the tank pressure enough to get through to steady fuel delivery. Learned this from RCers; see, they're not totally useless... "


Lou,

I believe this works for the RC guys because they typically run a pressure line from the muffler to their tanks. However, Steve didn't mention if he is running muffler pressure to his tanks. If he isn't, then momentarily plugging the muffler exhaust while cranking probably won't help prime his engine.
But I've been wrong before (just ask the wife ).

DennisV

>Steve, I have had partially blocked fuel filters cause this
>problem in the past. Smaller filters with very fine screens
>seem to be more critical. Hope this helps.

I have been using the really small filters from RO. Good suggestion and I will check it out before I fly again. Thanks.
Steve

Some years ago, at the Nats, the evening before 1/2-A Combat, everyone was happily testing out and running their engines - at that time, mostly VAs and AMEs. Easy starting, everything ran well. Next morning, no one could get their engines started, people were blowing plugs left and right, weird. The main difference was it was hot and humid. Really humid. Very unconfortable to be out. One guy with a Shuriken actually blew 5 Nelson plugs in a row, and that was before the action even started.

You're starting procedure is the culprit. Hand choking the intake may or may not pull in a consistent prime. In warm weather, when the fuel is thinner and the needle valve not partially plugged by congealed oil everything is fine. Castor oil especially will sit in the NVA and get thick. It may take several tries to get it out and it still can change the NV setting.

A key thing was the motor ran several seconds and then died. Classic symptom of not pulling fuel. Since these engines are on profiles it is easy to put a measured prime into the intake and then flip the prop 10 times or so to distribute it. Once you determine how many drops, or how full to fill the intake, you will again get repeatable starts.

Hey, if you're going to scrap a good running engine just because it doesn't start right send it my way. I'm not worried how many times to flip it if it gives me a good run.


Giff

I finally found the source of the engine run problems-Stunt judges! I flew the 25FSR today with no changes other than a clean fuel filter. I went through my normal pre start sequence and flipped it expecting a long effort for a cold start. It started on the first flip! Kieth Trostle commented something about that being natural, nothing works right on an official flight. I will try the .20FP tomorrow, but now I'm expecting that everything will be normal on it too.
Steve

Hi Steve,

One contest item I have tried to incorporate into my sequence is to burp the engines (not in the pits!) first thing. Then I know everything is cleaned out and ready to go. And I can check the system that way if I was not able to get in a practice flight before officials got started.

Big Bear <><
Character: It's what you do when no one else is watching.

its not the weather/fuel /plugs /stunt judges/ect--have no clue

this happenend to a group of us from alexandria once.

we all traveled togeather to contest usualy
5-6+ verry competent combat and rat types

at the contest(longveiw?)no ones engings would start.no stunt at this contest so no judges.
we all tryed diffrent fuels/plugs/ect cleaned tanks dissasembled engines and reassemble.borrowed fuel plugs batts ect from people from elsewhere.
cussed ect

we all had our own favorite after run oil ranging from wd-40 to none at all(castor oil days)

longveiw weather is always similar to ours in summer--possible degree or so warmer.similar humidity/baro pressure ect

everything was fine and normal after returning home

we still talk about this 30yr later(me and dad just 3 days ago)
and still dont know what happened other than he saw similar thing happen in ruston before i was born

we never thought about judges---wonder if one snuck in desquised as a combat fliers crew member?i will bring it up next disscussion.

still clueles after all these years
David

This happened to me in 1946 (in Atlanta, GA) trying to start my one-flip Bullet ignition engine. I swapped out the batteries, plug, coil, and condenser.

I could hardly sleep that night.

The next morning I woke up all the neighbors ... the Bullet started on the first flip.

I still think about that now and then.

talked to dad yesterday while working on race car.
i brought up the stunt judge idea to see what he thought.
the ruston group that he flew with before i was born-- it turns out that there was a stunt flier with them.
Chuck Andrews was his name(high flight score at nats in mid 60s?)
but he was only about 12yrs old (in 50s) when it happened--no ones engines from ruston would start at the bastroup contest.

the stunt gods and combat gods must fight from time to time?

still clueles for a reason as to why
David

Maybe one of those tiny little UFOs landed nearby?!

thats what I thought John
was just afraid to say it thought i would let someone else be first to be visited by the men in white coat

David
from the land where all thing are done-and seen

start a few thousand engines... then you'll have it down...i got a KnB 19 i do that with in my hand and run out the prime...no kiddin..almost every time one flip does it hey thats better than cuttin grass @ 100mph + inverted ....ill bring the 19 with me and show you if i get there next month...jim

I get along (MUCH) better with machines than I do with people. I have been able to diagnose and fix almost every mechanical problem that has come my way.

But the key here is ALMOST. I've come to believe that machines have some sort of soul and definately a unique personality.

As with all of life's mysteries, there are some things that will remain a mystery.