Scott Hersha
Well Known Member
I?m posting this thread to see if anyone here has a spec on the RPM limits on a Skytec 149NL 12 volt starter. I?ve tried calling Hartzell, but haven?t gotten an answer or anyone to call me back, so I figured someone here would surely know.
What is the design starting RPM spec for the Skytec 149NL 12 volt starter?
The reason I ask is because weve had a couple engine start issues. One of them was a kickback that sheared about 4 teeth off our starter ring gear. Seemed like a timing issue to me. We have a Superior XP IO-360 engine in our RV8. We are using 2 Pmags, and an EarthX battery. The Pmag is designed to set ignition timing for starting at where ever you timed the mag(s), normally at TDC. At 200 RPM, the Pmag automatically switches to run mode, normally 26.6* (I?ve retarded mine slightly - so 25* in run mode using the A curve in my case). My engine shouldn?t fire until almost 6* after TDC because of the built in 4.2* after TDC, plus the 1.6* that I?ve added. If the starter spins the engine fast enough, it can switch to the run timing before the engine has started. Using an EarthX, it has plenty of power to make the starter make it?s full potential. My question is, can this starter spin the engine that fast?? Jumping the timing to 25 before all the cylinders are making noise might be a problem.....
What is the design starting RPM spec for the Skytec 149NL 12 volt starter?
The reason I ask is because weve had a couple engine start issues. One of them was a kickback that sheared about 4 teeth off our starter ring gear. Seemed like a timing issue to me. We have a Superior XP IO-360 engine in our RV8. We are using 2 Pmags, and an EarthX battery. The Pmag is designed to set ignition timing for starting at where ever you timed the mag(s), normally at TDC. At 200 RPM, the Pmag automatically switches to run mode, normally 26.6* (I?ve retarded mine slightly - so 25* in run mode using the A curve in my case). My engine shouldn?t fire until almost 6* after TDC because of the built in 4.2* after TDC, plus the 1.6* that I?ve added. If the starter spins the engine fast enough, it can switch to the run timing before the engine has started. Using an EarthX, it has plenty of power to make the starter make it?s full potential. My question is, can this starter spin the engine that fast?? Jumping the timing to 25 before all the cylinders are making noise might be a problem.....
