another difficult start

[opticsguy]

It had been only 10 days since my last flight, and I could not get the plane to start. Luckily, the battery had a good charge. I let it sit for a few minutes and tried it again, nothing. I let it sit again for about 5 minutes and it fired a few times, then it started. I was worried that I had bad fuel again, but this time it seems like something different.

 

In my hangar it has been 120 degrees or more every day for weeks. Is it possible that the fuel had evaporated out of the fuel bowls and needed some cranking and waiting to get them filled up again?

[Runtoeat]

My CTSW will not start with full choke on initial start if outside temps are not "cold" (above 60 F). I must use "partial" choke as Roger suggests doing. If I've been flying in hot weather (85 F+) and park the plane for a few minutes and then re-start, my engine seems to not want to leap to life and I need to hold the starter after the engine starts and until the engine is fully running. I think I get some vapor lock from trapped heat in this situation and the engine starves for fuel initially.

[S4Flier]

Occasionally my Sting was harder to start after sitting awhile. Had this happen when I had the cowl off and my mechanic was looking on from the oustide after doing an oil change. He noticed that there was air in the gascolator. He suggested that if I notice that during the preflight, to run the aux pump until all the air is out. I had always run the fuel pump for ~5 seconds before starting (as per the checklist) but now run longer, when necessary. Haven't had to do this but a couple times but also haven't had starting issues.

 

Might apply to the CT as well?

[Runtoeat]

Hi Dave, your situation is similar to the old cars that the owners installed auxillary 6 volt fuel pumps in addition to the mechanical fuel pump run by the engine cam. The hot setup was to turn the electric pump on to raise the fuel pressure and get rid of fuel vapor lock, then start the engine. In hot summer weather, you could tell who the guys were that didn't have electric fuel pumps. They would be sitting in the drive-in and would be pouring ice water over their carb float bowl, fuel pumps and fuel lines, trying to get rid of vapor lock so they could start their cars. My CTSW does not have an electric fuel pump, just the mechanical pump, so I cannot turn a pump on before starting. Roger indicates this really isn't a concern and he's right since it just takes a few more turns with a hot engine than starting when cold. I have never had a "no start" when hot. 3 weeks ago, I flew 10 Young Eagles in 90 F+ weather and had approximately 12 hot starts in 4 hours time with no worries.

[N89WD]

We just got done with our Young Eagles project here in Afton. I flew 13 with all those hot starts with no problems either.

[Runtoeat]

Mike, good to hear that you're another pilot that's volunteering to promote our sport and get young people interested in flying. I have flown over 12 hours flying the Young Eagles so far this year and we all know that these hours must be accounted for when 100 hour inspection time comes up. The looks on the young kid's faces and their comments during the flights are worth it.

[N89WD]

The looks on the kids' faces really are priceless. The parents are as excited as the kids, with the pix and all. Hopefully other CT'ers get involved with the Young Eagles project. I would even recommend becoming an AOPA airport volunteer. I did it and have had alot of fun with it. Going Thursday to Idaho Falls to get my P/S done. Just a reminder to all, don't forget to get these biannually to stay current.

 

 

Happy Flying!

[opticsguy]

Update. Yesterday it was 97 degrees. I tried starting it without the choke, it almost started. I'll bet if I moved the throttle half an inch forward it would have started. Anyway, I put the choke about a third of the way and it started right up. I guess when it's hot, you can flood it with half choke.

 

Is no choke and throttle slightly forward the way to go on a really hot day?

[207WF]

Yesterday starting engine cold I had two failed attempts to start, then figured out that what it wanted was no choke and a cracked throttle. After that it ran smoothly. This has never happened before. But, the bird had been sitting for 2 weeks since flight (longer than normal), and I noticed the fuel cutoff was in the "on" position. I wonder if the fuel had worked its way into the carbs so as to make it too rich with the choke on? It was only about 75F OAT. WF

[Runtoeat]

207WF, did you try your start with full" choke or partial? You indicate that the engine started with parital throttle and no choke. Since you had tried to start two times prior to closing the choke and using the throttle, next time you do a cold start in warm conditions, a suggestion is to try the following with no throttle: 1/3 choke. If a "no start" then 1/2 choke. You may find that using partial throttle with no choke is still the best but finding the smoothest start method is good for the engine and good for the wallet as Roger indicates.

[bseager]

I recently noticed a change with cold starts (actually heated hangar so about 65 F). I have about 560 hours on my 2006 CTSW with 100 hp 912 ULS. Up until two starts ago the engine always started immediately using full choke with throttle fully closed. Last two times the engine would not start with choke and throttle in that configuration. Eventually started with about half choke but didn't seem happy. Any ideas on what might have changed? Could the choke cable be slipping? Hot starts work fine with no choke and throttle slightly cracked.

[FastEddieB]

As a data point, my starting got better, but still not perfect, with the SoftStart install several years ago.

 

When I did my annual last month, one of the things to check is the functioning and sychronizing of the "choke" cables - that they both go from fully open to fully closed with movement of the cockpit control.

 

Well, this time, the right one (your left - my engine is backwards) was WAY off. It was fully off when OFF, but only about halfway on when ON. I looked and looked and cannot figure out how it got that much off - the cables and adjusters are all safetied and I can't see where one off the cable ends could have gotten hung up on an adjuster or any other possible explanation.

 

Easy adjustment, but it did take several turns of the adjuster to get both carbs to "CHOKE -ON" at the same time.

 

Of course, having both "chokes" fully ON now did help, though sometimes it still will not fire with just the requisite "mag" on.

 

 

[opticsguy]

I can't believe this thread is still active. As the weather gets warmer, the more I find the choke to be useless. If it doesn't start right away, I go to no choke and a crack of throttle. With the soft start it runs really rough for 5 seconds, and when really cold, longer than that. It seems really rough, but I guess that' s better than backfires.

 

BTW, in the spring of 2012 I had the same problems, and Dean from Lockwood recommended replacing the ignition modules, which I did. The plane started instantly and has run great ever since. There have been about a dozen failures of ignition modules at low RPMs. Dean thought Rotax would pay me back my $900 for the modules, but after a year not even a courtesy email from Rotax.

[opticsguy]

Since replacing the ignition modules at my expense, the engine has started instantly in all kinds of weather. Rotax has ignored my inquiries about this issue for over a year.

[opticsguy]

I sent such report to Dean at Lockwood a year ago. If you have another email to send it to, I will.

[opticsguy]

I have a SIR ready. I sent the defective parts to Lockwood and they can't find them. Who would I send this form to?

[opticsguy]

Is there a person there I should try to email?