proper way to shut down engine

[slam555]

no when I was spraying arou8nd the hose connections, I was also looking and feeling around the clamps, didn't see any bubbling, but did notice that 2 clamps weren't tight, of course the leak could've been at the top, but anyway it was a good idea and helped to ensure everything was good,
after another warm up run I'll be doing it again, I'm hoping to fly it Friday, if the winds aren't too bad,

[Ragwing nut]

Merry Christmas to one and all, spent the morning at the airport, did the intake manifold test, found some things that need to be tightened up, double checked everything else, hooked up the lean mix lever, and set the idle mixture screw to the same as the old carb, buttoned it up and took it outside the hanger, it was windy but warm, and it fired right up then quit,. and wouldn't fire any more even if I primed it, then it occurred to me that the fuel was off. because I was working on it and spinning the prop. turned the fuel on 2 primes and it fired looked at the A&P and he was waving for me to shut it down, it was popping and air was coming out the front of the carb. but it did start and run on its own.

Since we did the mags I have had the timing checked 2 more times, each time I was assured it was correct, but it couldn't be, so this time we reset it to 28 degrees, and the double checked that it would spark at TDC, and it did. One more check of the bolts, and buttoned it up again, 2 primes, and it ran, solid, and steady, I had the wheels chocked and the brakes on got it up to 2000 rpm's no issues, let it run between 1000, and 1500 and watched the E-G system tell me what temps the cylinders were running, looked at the oil temp and pressure all good, the 3 cylinders all rose in equal increments, but no.4 ran 50 degrees cooler, so the exhaust valve, isn't sticking, but it also isn't sealing as good as the others.

so thats the next project, I'll be ordering from spruce for a valve spring compressor, lapping compound, 25' of rope, 3/8 tubing. and my bore scope should be here any day now.

Meanwhile the A&P was shown the valve for the fuel shut off and we'll be bringing that up to date.

Thanks guys for all the help and suggestions, now that its running, its a great relief. and I can get back on schedule for the rest of the list. On another note, I know the mags are good for another 500 hours, and so should the carb, not to mention the mounts, all give me more peace of mind for flying.

please check out the Savvy aviation website for their seminars on the continental, they were also a big help

So besides a timing issue, it did have an intake leak?

[slam555]

Merry Christmas to one and all, spent the morning at the airport, did the intake manifold test, found some things that need to be tightened up, double checked everything else, hooked up the lean mix lever, and set the idle mixture screw to the same as the old carb, buttoned it up and took it outside the hanger, it was windy but warm, and it fired right up then quit,. and wouldn't fire any more even if I primed it, then it occurred to me that the fuel was off. because I was working on it and spinning the prop. turned the fuel on 2 primes and it fired looked at the A&P and he was waving for me to shut it down, it was popping and air was coming out the front of the carb. but it did start and run on its own.

Since we did the mags I have had the timing checked 2 more times, each time I was assured it was correct, but it couldn't be, so this time we reset it to 28 degrees, and the double checked that it would spark at TDC, and it did. One more check of the bolts, and buttoned it up again, 2 primes, and it ran, solid, and steady, I had the wheels chocked and the brakes on got it up to 2000 rpm's no issues, let it run between 1000, and 1500 and watched the E-G system tell me what temps the cylinders were running, looked at the oil temp and pressure all good, the 3 cylinders all rose in equal increments, but no.4 ran 50 degrees cooler, so the exhaust valve, isn't sticking, but it also isn't sealing as good as the others.

so thats the next project, I'll be ordering from spruce for a valve spring compressor, lapping compound, 25' of rope, 3/8 tubing. and my bore scope should be here any day now.

Meanwhile the A&P was shown the valve for the fuel shut off and we'll be bringing that up to date.

Thanks guys for all the help and suggestions, now that its running, its a great relief. and I can get back on schedule for the rest of the list. On another note, I know the mags are good for another 500 hours, and so should the carb, not to mention the mounts, all give me more peace of mind for flying.

please check out the Savvy aviation website for their seminars on the continental, they were also a big help

[slam555]

ok today was quite interesting, on the compression front, it all looked good, my compressor has a small tank so I had to refill it for each cylinder, found that no.4 was stuck again, so its definately going to get lapped and the stem cleaned up. but when the valve was closed the compression was at 68 and that's a cold engine test no 3 was 65, no 2 was 70 and no 1 was 72

I looked at the drain plug and decided that it was a good idea to leave it alone, someone already chewed the edges up and I would look for another way.

I still have the old carb to look at and work on so I took an air hose and put it to the fuel opening gave it some air and it hissed. after checking the fuel screen, I did the same to the new carb and fuel flew out everywhere, then I looked at the idle mixture screw, and how many turns it took to wind it in, which was a little more that 2 1/2, so Wed when I can get back out there I'll set the screw close up the cowling and try it again, even on 3 cylinders it should start.

if I get the chance I'll check for intake leaks also, I've noticed that there are quite a few small planes at this airport with no cowls and continentals on them, getting this one to run, might help them out as well, and I know my A&P is interested he's been as baffled as me on how and what to test

after all this WHEN I get it running, it will be tested on the ground before we take it in the air, and then the first flights will be short with the cowls coming off afterwoods to check every nut and bolt touched, I don't want to risk anyone's safety. just saying

[slam555]

Mike, makes an good, next diagnostic test suggestion. Clean out your shop vac really, really well so it dose not blow dust into your induction system. Put the hose on the vac exit and then seal it up on the carb intake with the throttle open.
Get a spray bottle with soapy dish detergent and spray all the joints from carb to cylinder intake tube flange/clamps.

Might as well test for exhaust leaks while your at it.

great Idea, easy enough to do, will have to rig up something for electricity

[slam555]

sounds to me like you have an intake leak.

we've check the hose connections to the manifolds, and the carb has new gaskets, but we haven't checked the connections to the cylinders, so I don't know but will have to look

[Mark Bowden]

Mike, makes an good, next diagnostic test suggestion. Clean out your shop vac really, really well so it dose not blow dust into your induction system. Put the hose on the vac exit and then seal it up on the carb intake with the throttle open.
Get a spray bottle with soapy dish detergent and spray all the joints from carb to cylinder intake tube flange/clamps.

Might as well test for exhaust leaks while your at it.

[Ragwing nut]

radio fixed Springfield
ran rough on start but smoothed out after warm up flew home from Springfield
next day wouldn't make power, was told it was mags, Mags had 500 hours on them ( was stuck valve)
new mags in still no power found stuck valve but engine did start
engine backfired not able to get it started
still no start, was told carb was in bad shape.
new carb, new mounts, still no start, only way it would fire if it was primed while turning it over
fuel flow was checked before we hooked up ne carb,
need to know if carb HAS FUEL in bowl, or valves are stuck for no compression
Its been mis diagnosed by A&P qualified people. ( this is why I have trust issues)
it also could be the adjustment on the idle for the carb, all of this I will look at Sunday,
it is probably the cylinders and my exhaust valves need to be lapped I won't know till the bore scope arrives
I have been looking at webinars from "Savvy aviation on this"

sounds to me like you have an intake leak.

[slam555]

[ATTACH]n197540[/ATTACH]

[ATTACH]n197539[/ATTACH]

Over time I have scanned the best drawing quality of the drawings I've collected into the two pdfs. They may be of some help. I had to split the file into two due to upload limitations.

Those are great, I have them in a book but you can't read them,
my tank valve is nothing like that one but it looks correct for the era of the plane, that's another issue to fix on the plane before we fly again. at least now I can get some part numbers and read the specs.

thanks very much

[slam555]

fully rebuilt mages were from aircraft spruce, the plates were photographed so we could confirm the numbers they are slick mags,
the carb came from Aircraft supply, it was totally overhauled and had signed papers that it was inspect and tested before it was sent out.

My A&P put the mags in I helped, although I wasn't much help, I've neve done mags before. he used a wire clip to find the number 1 cylinder on the mag we set the prop to the no1 firing position and he installed the gears to the mag and then to plane, after they were in he had a timing device to double check it. I also got ne wires, and the plugs were freshly cleaned and tested, since then I have double checked wires and anything I could to make sure it was correct, the plane was started and wouldn't make power, just like before we did the mags,

after the failed test run, we opened up the valve covers, to which we found cylinder no. 4 had a stuck exhaust valve. I popped it back to close and added in some penetrating oil and seafoam on the spring and tried to get some on the valve, I didn't have a scope so I couldn't see if I got any in, but within in 2 rotations the valve started working again no assistance needed.
the next time I could get out to work on the plane it wouldn't start it would pop, but no continuous firing, definately a fuel issue, it did backfire, which caught the hose to the carb heat on fire,
after putting it out I called the A&P and we decided to replace the carb, and change the mounts, the mounts took us 45 minutes, and the carb took us 6 hours, just to get it installed and now it still sputters with the prime but no fuel from the carb, I also got a new fuel line for the gasolater to the carb and double checked the fuel flow from the tank, no issues there

so this is where it sits, new carb, all the hose's and lines hooked up, and no fuel. tomorrow, I'll remover the fuel line and force some carb cleaner in the carb, if there's fuel in the carb it'll leak out the bottom of the carb heat box, if it doesn't the carb is the issue, I will also take some compression readings, if there is a valve stuck or cracked rings the compression test will let me know something is wrong, my scope will be here after xmas, and then I'll be able to check the cylinders and the valve's , cylinder no.4 will be getting it exhaust valve lapped, and get some of the build up off the stem. worst case scenario is cylinder replacement but I want all the info and documentation first, no more second hand guessing

[Mark Bowden]

You mentioned "new" mags, generally your A&P would send them out to have them rebuilt. What shop rebuilt the mags?
I use Quality Aircraft Assoicates in Tulsa, OK.

Who timed the mags on installation, did you witness/help the process?

You mention a "new" carb, was it sent out for an overhaul? What shop did it, or did your A&P do it?

If you are checking/adjusting the idle mixture screw be careful when screwing in to the stop, only use your fingers and don't tighten it hard. You can damage the mixture needle tip.

[Mark Bowden]

Taylorcraft BC-12D airframe Prints Part 1.pdf

Taylorcraft BC12-D airframe Prints Part 2.pdf

Over time I have scanned the best drawing quality of the drawings I've collected into the two pdfs. They may be of some help. I had to split the file into two due to upload limitations.

[slam555]

I appreciate you guys more than I can say,
the more I think about it the more frustrated I get
I hate wasting money especially mine, but when I look at the logs, and see the parts, the mags were due for a rebuild or replacement, and the carb has loos parts on it as well, my engine mounts showed cracks at the edges which says needs to be addressed so in the long run I'll have things done the way their supposed to and know when I'm in the air, that the engine is solid, and shouldn't let me down Thanks again Sam

[slam555]

Slam, please put in chronological order what has happened and what has been done. There may be something that pops out that will aid troubleshooting.

radio fixed Springfield
ran rough on start but smoothed out after warm up flew home from Springfield
next day wouldn't make power, was told it was mags, Mags had 500 hours on them ( was stuck valve)
new mags in still no power found stuck valve but engine did start
engine backfired not able to get it started
still no start, was told carb was in bad shape.
new carb, new mounts, still no start, only way it would fire if it was primed while turning it over
fuel flow was checked before we hooked up ne carb,
need to know if carb HAS FUEL in bowl, or valves are stuck for no compression
Its been mis diagnosed by A&P qualified people. ( this is why I have trust issues)
it also could be the adjustment on the idle for the carb, all of this I will look at Sunday,
it is probably the cylinders and my exhaust valves need to be lapped I won't know till the bore scope arrives
I have been looking at webinars from "Savvy aviation on this"

[slam555]

If you suspect fuel flow issue, start your diganostics at the beginning of the process, in this case the tank.

Get a jug that can measure liquid volume. Ground the aircraft like you do at the gas pump, a wire to a metal post in the ground or building. Open the doors and be well ventilated.

Shut off the main tank fuel valve, remove the lower cowling. Disconnect the fuel line to the carb. This will verify that the valve will actually stop flow, obviously important to your orginal question on shutdown.

Put the gas line into the jug, open the valve and start a timer. Drain a half gallon, observe the flow, it should be signifigant. After you have a 1/2 gallon figure out your fuel flow in gallons per hour. You should be above 6 gph. Someone can chime in with what the minium should be with the tail down.

If you are not at 6 gph or well above you have a fuel line, valve, tank screen or gascolator restriction. The tank vents through the cork float cap.

Then move on to the carb. The Stromburg for all the people that cursing it, it is actually an ingenious design.
Even if you remove the bowl drain plug it will not clear the sediment entierely as it is above the bottom of the bowl.

As Rob stated, if you try to open it and it has not been out in a while you risk cracking the bowl. Same for the metal screen Thimble Fuel Filter big nut cap. Do NOT ever crank hard on this with a wrench. Get fuel lube or EZ Turn, coat the nut, washer and bowl and snug it up, then safety wire it back.

Have you checked your gascolator screen and the carb filter screen?

I'll try and give you a call this weekend. You will succeed, keep at it.

ITS A NEW CARB I checked the fuel flow before we hooked the fuel line up