Maintenance: Starter failure #2. Replaced with different model: 149-NL.

My factory original SkyTec 149-12LS starter failed at 43 hours.  It suffered from the well-known sticking of the solenoid.  The replacement starter failed with the same issue at 103.9 hours.  Not wanting to see a third instance of this issue, I asked SkyTec (now Hartzell) if they would replace my 149-12LS with a 149-NL, which they did.

The 149-12LS has an adjacent solenoid, is 8.25 pounds and uses a permanent magnet motor with a 3.7:1 reduction gear.  It has a strontium-fortified 356 T6 aluminum alloy mount, needle bearing in nose, brass bushing in rear.  160-180 RPM at 11 V, 185-285 A.

The 149-NL has an inline solenoid, is 9.3 pounds with a series wound coil and 6.5:1 reduction gear.  It has a field-replaceable shear pin for kickback protection, die cast A-380 aluminum mount and 3X steel ball bearing races.  ~120 RPM at 11 V with 85-125 A. 

 

 

Here are the two original, failed 149-12LS starters.  When they were both removed they each had ejection of packing grease which the Hartzell technician assured me was normal.  Original 43 hour 149-12LS starter on left (from 20-May-18) and replacement 103.9 hour 149-12LS starter on right.

Now on to the third starter...There are four bosses on the 149-NL starter.  Boss A is for the V-1002 alternator-to-starter link (see plans page 43-12).  For the IO-390, bosses B, C and D can be removed, per Hartzell's instructions, to within 1/8" of the casing (see ST25001 Rev. J).  I did that with a cutting wheel on a Dremel then smoothed things down with a light grinding wheel (bottom left and right images).  Boss D doesn't have to be removed for use in the RV-14A, but might as well trim off the ounce of weight.

The 149-NL starter fits fine on the IO-390.  However, in the RV-14, the mixture bracket assembly (see page 50-03 and OP-22) has a F3414M Rod End Bearing that binds against the starter casing.

To alleviate this issue, I moved the Rod End Bearing to the outboard side of the Mixture Arm (it was easier than changing the clocking of the arm then making gross changes in the cable length).  Some changes in the washer stack and readjustment of the mixture cable travel was necessary to ensure full Mixture Arm travel and compliance with the "vital criteria" on page 50-02 (stoppage is achieved by the control stop, leaving a 1/16" cushion gap).

The next unknown was if the cable going to the starter would be long enough for the 149-NL (the 149-12LS has its terminal about an inch further aft).   

Turns out that the original WH-P16 Starter Relay to Starter Wire has its spade connector bent in page 43-11, Step 2 (visible above).  Upon bending this back and taking up some of the slack in the cable, it reaches the new starter just fine.

 
The next issue was the Van's wiring approach.  Van's has the "I" terminal of the starter contactor on the firewall connected to the 149-12LS starter with the K910 Starter Disengage wire (see page 43-04), shown as the little hanging wire above.  They do that to eliminate "hesitation in disengaging from the ring gear" (the LS has an internal contactor).  There is no provision on the 149-NL starter for that approach since the starter's "S" terminal has been "repurposed" for use as selecting either 12 or 24 Volt operation through the use of a jumper.  Thus, one can remove the Starter Disengage wire with the 149-NL.  But, this would leave the "I" terminal on the firewall starter contactor exposed (ES 24021 on page 43-04).  So I just cut the wire at the spade lug and used a wire-tie to affix the nipple in place.  Below are views of the starter contactor showing that nipple on the "I" terminal from above (left) and below (right).

The 149-NL starter gear sits in the same place as the 149-12LS' when retracted.

The next unknown was if the VA-132-2 Snorkel fitment would be impeded by the new starter.  Thankfully, there was more than enough clearance.

The 149-NL starter has more torque than the 149-12LS and it sounds more stout.  Hopefully the 149-NL is of higher quality too.