New Hot Start Problems

[odens_14]

I fly an RV-7 with the IO-360 w/ slick mags it has about 400 hrs on it. Recently, I've had trouble with hot starts. I use the full throttle mixture cut-off dance; which up until this summer has worked without fail relatively quickly. Lately it's been much more difficult to start hot, or even warm after it sits for an hour or so. Every time except once I was able to get it started eventually but took a fair amount of cranking which is not normal (and to be honest slightly embarrassing when you're at a fly-in with people watching ). Cold starts are no issue and it usually fires after 3-5 blades. No other anomalies once started.

I guess my question is where to start looking, it feels like ignition but I'm not sure. Spark plugs looked fine in May, mags haven't been touched. second option is I'm just out of practice with the dance and its pilot error, but it doesn't feel like I've changed anything.

[Carl Froehlich]

Agree - I?d first look at the igntion starting with cleaning, gap and ohm check of the plugs.

I had 8 of 12 Champion plugs with out of spec high resistance in less than 300 hours (back when Champion had this problem). A new set of Tempest plugs made a huge difference.

Carl

[Raymo]

If it is true that the mags have not been touched in 400 hours, you'll want to check timing, which is recommended every 100/CI/annual by Slick. They recommend your IRAN them every 500.

[odens_14]

Originally Posted by Raymo

If it is true that the mags have not been touched in 400 hours, you'll want to check timing, which is recommended every 100/CI/annual by Slick. They recommend your IRAN them every 500.

yes, I've check timing but never needed any adjustment. I also know about the 500 thing as well, I'm hoping mine didn't give up 100 hours early!!! I'll pull the plugs again and see if that tells me anything.

[lr172]

Timing and egap (this affects the strength of the spark) will drift on a mag after a 25-50 hours on most new mags as the points and cam wear in. Recommend checking e gap and timing after the first 50 or so hours and then should be relatively stable stable until the 500 hours, though some wear and commensurate drift should be expected.

Larry

[6 Gun]

I had same problem and it was my impulse mag needing new points.Something to check.
Bob

[Robert Anglin]

Check your points, condencer, and plugs on an Ohm meter. Slick also had a S.B. for the breaker cams and carbon rotor contact to be replaced. You may want to try an old trick we use from time to time with this being an IO-360.
Sometimes if it is really hot and we shut-down for just fuel and a nature break that is only a few minutes before we want to fire back up, we try this.
Mixture rich,- Throttle just open a little so it will idle after it catches,- start turning and bring the bust-pump on just after we start turning. If it or when it catches, turn the bust pump off as soon as it catches, and then chase the throttle to keep it running till the vapor clears from the spider lines and the engine settles down smooth again. This one is not in the books, but we have fount that on an "IO" that does not like you, sometimes it gets us going. The fuel lines will be hot and once you get running, you will have to set there and wait till it has settle and those hot lines have solid fuel flowing smooth threw them again. Just something to try if you wish. Yours, R.E.A. III # 80888

[Larry DeCamp]

Mag shops tell me in addition to Egap, magnet ?remagnetizing ? is a key to spark strength. I experienced it first hand on an antique engine, night vss day on hand prop hot starts .

[Pat Stewart]

Boy I feel your pain. I try not to use the hot start technique unless absolutely neccesary because I fear a back fire and a fire from it. I usually start it with the throttle cracked and mixture at cutoff. If that does not work I try starting with mixture in and then back out. Most of the time it starts but it shakes for 30 seconds or so before it clears up. I don't like the shake.

[Boyd Birchler]

Check the cams in the mags. On a Slick the cam is a little plastic paddle, there was a batch of them a few years back that wore very quickly.

If the points are not opening enough because of a worn cam starting will be tough.