Hard starting A-75 with slick impulse mags

[M Towsley]

Re: Hard starting A-75 with slick impulse mags

Steve,

Just to let you know, my engine will start at idle but it likes it better if I barely crack the throttle. At idle it is ticking over fairly slowly until I can get back to the cockpit and give it a little throttle. And barely means, just ever so slightly when you crack the throttle!!! Good luck.

[Ragwing nut]

Re: Hard starting A-75 with slick impulse mags

Compression was great at the last annual, all in the seventies, with three at 75.

Mike, I don't know about the mag timing, and I'm not confident enough to check it myself. I like to at least watch someone else do it first, or have someone watch me do it.

I'm now leaning towards the mag timing or opening the throttle too far when trying to start it. I'll try to start it sometime this week with the throttle closed and see if that is my problem

Thanks for the tips!

Also I know already mentioned, where does the prop sit when ready to pull through? Should be roughly 10 and 4. Also is it a dual impulse conversion? If a single, are you starting it only on the left mag?

Mike

[astjp2]

Re: Hard starting A-75 with slick impulse mags

Get a set of SF-4's, I have them on mine and cold is 1-2 pulls, The guy that rebuilt mine told me if I have slicks that I should "remove them gently and hold them close as I walk over to the largest trash can and slam them in as hard as I can possible throw them and get a set of bendix"....that was his quote

I thought it was funny!
they may need a 500 hour service...that might fix things....Tim

[alwaysoar]

Re: Hard starting A-75 with slick impulse mags

Here's another tip: When you shut down, advance to full throttle as you turn off the mags. The engine will turn over a few blades after the switch is off with full throttle. That worked for me before I got my Slicks (best thing since sugar on snow I don't care what that guy says.)

[n6346m]

Re: Hard starting A-75 with slick impulse mags

Richard,
How do you describe the Squishy sound to anyone who has never heard it?
I recognize it every time and I know it's time to turn on the mag. How do you describe this to someone who has always had a starter?
Bob

Steve,

I have an A-65 Cont with a Stromberg carb on my Taylorcraft. I do not have a primer. I prime my engine by pulling it through several blades with the fuel on. The number of blades depends on air temp and how long since the engine has been run.

If it is 70 degrees and I haven't ran the engine that day, I pull through about 6-7 blades with the fuel on and the throttle cracked 1/8". By the 6th or 7th blade I can hear a squishy sound from the fuel in the carb. Then I CLOSE the throttle completely. It usually starts on the first pull, but I have to get to the throttle imeadiately to crack it open just a hair. I do that by starting on the passenger side from behind the prop.

This is what works for me. I began closing the throttle completely after reading about the Stromberg carb in a book from Sacramento Sky Ranch. Prior to that I had always started with the throttle cracked 1/8". Once I began starting with the throttle completely closed, my engine was much easier to start.

[Pearson]

Re: Hard starting A-75 with slick impulse mags

It sorta sounds like when you squeeze the excess water out of a sponge. hope that helps. If you see fuel dripping, you missed the sound and primed too much. Hope this helps.

[NY86]

Re: Hard starting A-75 with slick impulse mags

Strombergs prime best (make the squishy sound) with the throttle all the way closed. I usually pull it through 4 blades on a warm day and 8 or even 12 on a cold day, then open the throttle about 1/8", turn the mags on and flip it once and it goes.

An induction leak will lean out your starting mixture.

[n6346m]

Re: Hard starting A-75 with slick impulse mags

Here's another tip: When you shut down, advance to full throttle as you turn off the mags. The engine will turn over a few blades after the switch is off with full throttle. That worked for me before I got my Slicks (best thing since sugar on snow I don't care what that guy says.)

Be careful using this technique. Most non-Stromberg carbureted engines recommend shutting down the engine using the mixture control instead of the turning off the ignition. Since the Strombergs do not have this feature we have no choice but to turn off the mags when shutting down. Using the mixture control to shut down accomplishes two things. First it rids the cylinders of most of the fuel and reduces the amout of oil that is washed down the cylinder walls creating obvious wear problems in the long run. Second it reduces the chances of the engine "dieseling" on it own with the ignition off. I just don't think it's a good idea to introduce extra fuel into the cylinders on shutdown. Just my 2cents worth.
Bob

[dedrekon]

Re: Hard starting A-75 with slick impulse mags

Since I fly 90% of the time on MoGas, I generally turn off the gas as I'm taxiing. If I time it just right it will run out of fuel right in front of my hangar. It may or may not help keep things from getting gummed up, but it couldn't hurt!


v

[stormman]

Re: Hard starting A-75 with slick impulse mags

As others have said , CLOSE the Throttle

[alwaysoar]

Re: Hard starting A-75 with slick impulse mags

Being a beginner in all this I defer to "old timers" who say open the throttle after turning off the switch to let the engine rotate a few blades to clear the engine. And I refer to the "Taylorcraft Service Manual" that states on page 20: "If the engine does not start immediately it may have too much fuel in the induction system. The switch is turned off, the throttle opened all the way and the prop pulled through several times in the normal direction of rotation. It is a common miscomception that to rotate the prop backwards clears the engine. There is no basis for this thinking."

Stopping the engine with the throttle closed may actually be loading up the induction system; stopping with the throttle open may help to clear it.

Ed@BTV VT
TF 527

[n6346m]

Re: Hard starting A-75 with slick impulse mags

Yes, I agree with a wide open throttle to clear the engine since you want to get air in the cylinders and displase the unburned fuel. You must do this with the mixture in cut-off position if you have a mixture control or the fuel valve shut off if you dont or else you'll flood the engine even worse and never get it started, especially if you have one of those "drippy" Strombergs with gas leaking out of carb air box while you are pulling the prop through. This is my third A-65 with a Stromberg and they pretty well all have behaved the same.
Bob