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Moster 185+ Flash Starter Issues :: A Vittorazi Trilogy


new2net
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I have a pull start Moster 185+, which has been great up until about 125 hours. I haven't had any issues or work done on the aside from routine maintenance on the engine, even the exhaust is perfectly fine. I also never needed to play with the carburetor either - it has always been a smooth running engine until these starter issues came up.

Issue 1: My engine stalled mid flight after about a 3.5 hour flight. I heard a "clink" sort of noise, almost like a coin hitting a metal pipe. The engine came back from stalling and again I heard another "clink" a couple minutes later which stalled the engine completely. I had plenty of landing options, so it wasn't an issue and actually landed back at my intended LZ thanks to a few thermals. Upon initial inspection, I notice that pulling the starter only pulls slack out, and it does not recoil at this point.

664453479_issue1.thumb.jpg.1fd0ee8260470a638f2c516294bef386.jpg

 

Fix 1: Upon removal and inspection of the starter, my starter had only one plastic hook out of two, and the elastic clip which holds the hooks in place was sheared into two pieces one of which was missing. Upon removing the starter, it was noted that the parts of the missing plastic hook were bouncing around in the space between the starter and the flywheel. The shim washers between the elastic clip and the starter also had grooves worn into it in the pattern of the elastic clip itself which I imagine could only be from vibrations during 125 hours of flying. My assumption here is that symptoms of a stalling engine were due to the elastic clip and plastic pieces which broke off getting jammed between the starter and flywheel mid-flight. The elastic clip being metal, caused the "clink" noise when it was caught and promptly ejected by the metal flywheel. My fix was to purchase new plastic hooks (MP055), a new elastic clip (MP057), a shim washer set (MP056), and a new pull starter cord because mine was starting to look a little worn (M043). I attempted to match the original width of the shim washers using my set, but could only get close. I think it was slightly wider of a shim set that was originally put in. In the image attached, it looks like the original shim set has grease lines on it in the shape of the elastic band - those are actually the elastic band wearing into the metal of the shims.

 

 

Issue 2: Excited to fly again, I set my gear up and give the starter a good pull. Everything is working as expected, or so it seems. I land, and a couple days later go out to fly again. This time the pull cord again only pulls out and doesn't recoil into the starter. I inspect my engine and notice that two of the starter mounts have sheered off. See "issue 2.jpg" and "issue 2+.jpg"...

1413771509_issue2.thumb.jpg.cce1d865386e787604bdaad8327aefd3.jpg

1340443803_issue2.thumb.jpg.3fe3a141c6eed6d4c2bc8144964cda65.jpg

Fix 2: The lack of recoil was due to the shim set being too tight of a fit, so I replaced it with one slightly smaller than the original shim set that came with my starter, which allowed for enough play that the starter would recoil correctly. As for the sheared bolts - I did not have a gear puller handy, so in order to avoid taking off the flywheel and replacing the starter mounting plate entirely, I tediously worked the sheared bolts out using some ingenuity to work in the tiny spaces. I rethreaded (cleaned) the threads in the starter plate to clean them up some, and the replaced the two sheared off bolts and spacers with new parts (2 × MP046 Spacer for the Starter Structure). Everything seems fine, the hooks, shims, elastic ring clip and all of the previous repairs seem to be intact and without issue. The plate itself wasn't really damaged and there was still plenty of flat surface for the spacers to rest on.

 

 

Issue 3: I go to take off, once again really excited that the repairs weren't that hard and takeoff starts off really well. I get about 100 yards out and then I get slapped in the back of my neck with something. My plan is to stay the course and solve the issue later, because the engine is still going strong. Upon landing I notice my entire pull starter cord is missing along with the handle - so the cord must have been jammed somewhere and snapped. The handle is what must have hit my neck. Upon removing the starter, I notice the cord somehow got into the shim washers and started to wrap around the central pin (MP044 Starter Central Pin) of the starter itself. The cord, being synthetic, was melted around the area the shim washers go and also was wrapped up in the elastic ring which holds the plastic hooks in place. I suspect the cord was somehow wrapped up in there, and this is what ended up breaking the pull start cord, which sent my pull start handle flying - never to be found again - R.I.P.  I noticed one of the shim washers was completely snapped and the other bent - most likely from the pull start cord being wrapped in there so tightly. This also bent the elastic clip out of shape.

1442612708_issue3.thumb.jpg.71282c0d3f1cebd16bbbcff4bbf4e4d3.jpg

511050754_issue3.thumb.jpg.3f840ebfd46ad86790e494568478b03f.jpg

Fix 3: So I'm in the middle of my 3rd fix. I'm tempted to just buy an entirely new starter at this point for roughly $260, but the one I have seems completely salvageable for $40 of parts... I purchased the parts Starter Handle (MP059), Pull Starter Cord (M043), Elastic Ring for Hooks (MP057), and another shim washer set (MP056). Unless I get some advice otherwise, I plan to just replace them as previously done. I have no idea what allowed the pull start cord to get stuck between the starter and flywheel like this which is really a bit more concerning than the other 2 previous issues. I had correctly charged and set the starter cord inside of the pulley that keeps the cord on the starter coil track where it normally rests. I had replaced it like always, etc. I had pulled the pull starter a good 15 times without issues when testing the repair before flying and the engine started each time during my tests between Fix #2 and the flight immediately after which caused Issue #3. I have no idea why the cord wasn't sucked into the starter sooner than 20-30 seconds into the flight...

Basically my question is: does anyone know how issue #3 could have occurred so I can correctly address it during the fix?

vittorazi pull start diagram.png

Edited by new2net
added another picture of issue 3
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10 hours ago, new2net said:

I have no idea what allowed the pull start cord to get stuck between the starter and flywheel like this

Owch... That would bug the life out of me unless I grasped how.
I'm guessing that some friction somewhere has griped the system and unwound the chord which has snagged and been wound around the live portion of the system.
Polini had a recurring issue with one of their starters unwinding the chord (if my memory serves me)

I don't think this is the thread I read but its a start:
https://www.southwestairsports.com/ppgtechinfo/polinithor/flashstarter/flashstarter.htm

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On ‎31‎/‎08‎/‎2020 at 23:28, new2net said:

The lack of recoil was due to the shim set being too tight of a fit, so I replaced it with one slightly smaller than the original shim set that came with my starter, which allowed for enough play that the starter would recoil correctly.

I "think" the slop is somewhat critical, too much and it can allow a resonant vibration to begin transferring torque across that gap via the "shim".
One guy added a fiber washer to act as a damper preventing the resonance taking hold... not sure how long that would last.

Looking at your photos, the wear looks like it might slowly increase slop until it hits the sweat spot where a sympathetic resonance can take hold of the system and self-destruct in very short order.

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  • 1 month later...
  • 2 weeks later...

The saga continued actually a bit further.

Fix 3: I replaced the broken and missing parts: Starter Handle (MP059), Pull Starter Cord (M043), Elastic Ring for Hooks (MP057), and another shim washer set (MP056).

Issue 4: When I went to charge the starter the spring would slip and release around 4 revolutions, despite the instructions being clear on 6 revolutions are required and despite my previous experience charging the starter.

Side note: Search YouTube for the "Moster 185 Starter Upgrade" video published by Vittorazi to see what I mean about charging the spring inside of the starter- you have to wind it up 6 revolutions and then let 3 of those out to wrap 3 loops of rope around the starter. Also, since I already have you avid readers taking notes, consider this: you should wear some safety glasses if you decide to open the flash starter and peek at the spring: it could be under a lot of tension, and rapidly decompress when it slips out of the starter body.

I noticed not only did it fail to fully charge 6 revolutions, but it would also fail to fully recoil, even if you only did 4 revolutions it wouldn't recoil 4 revolutions, but instead make a sort of noise as if it let all of the tension out immediately and slipped inside of the stater body. I think this explains how issue #3 actually occurred. The spring (MP051 Recoil Spring) wants to recoil and draw the starter cord back around the pulley so that it's wrapped around the pulley 6 times to release the tension from the initial charging. That spring was broken or at the very least slipping around. So when I had managed to get my engine started immediately prior to issue #3, I think the starter never recoiled fully which allowed the pull-start-cord that is normally taut to go slack and get stuck between the starter's plastic hooks and the teeth the hooks interface with inside of the flywheel. Ultimately, the pull start cord fought the engine mid-takeoff and it snapped, sending my pull-start-handle flying. I suppose it's also possible that the carnage did the damage to the spring instead of the spring failure causing the carnage...

Fix 4: I bought a completely new starter assembly for around $250. Yes, technically I could try just replacing the spring (MP053 Easy Start Spring & MP051 Recoil Spring) for $38 along with the Strapping Band (MP053a) for $2, but at this point I really just want to fly and I don't want to keep chasing down starter issues... Moreover, I'm already $100+ into starter replacement parts and I'm not even guaranteed replacing the springs will result in a working starter. I did not try and rebuild the starter further, although I did keep the part in my box of paramotor accessories/parts. I'm sure it can be fixed, but I really just want to go flying.

I've been flying at least 10 times since then and I must say the new starter works better than ever. I can even kill my engine mid-flight and I'm not worried about pull starting it again also mid-flight.

 

easy-starter-spring-and stapping-band.jpg

recoil-spring.jpg

Edited by new2net
adding a zoomed in view of the starting spring I'm discussing in issue #4.
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15 hours ago, new2net said:

The saga continued actually a bit further.

Just going to add this NOT that it helps you now but broken aluminium starter mounts normally only break after something has been replaced in the starter, and when refitting it in most cases people do not hold the mounts with a spanner before tightening the four securing bolts, and this in turn either loosens the aluminium mounts or they tighten up causing failure later.

Vittobroken starter..jpg

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  • 9 months later...
On 12/10/2020 at 13:55, kiwi k said:

Just going to add this NOT that it helps you now but broken aluminium starter mounts normally only break after something has been replaced in the starter, and when refitting it in most cases people do not hold the mounts with a spanner before tightening the four securing bolts, and this in turn either loosens the aluminium mounts or they tighten up causing failure later.

Vittobroken starter..jpg

I realize this post is a year old but I have just had this same issue happen to my upper starter mounts on my moster 185. Sheared completely through and badly gouged out their mating surfaces on the carter support.

I had to replace  some parts on my starter a few months ago so I seemed to have made the mistake you have pointed out here.

I got a new carter support and starter mounts coming, but my question is: how firm do I torque these mounts/spacers to the carter support before I finish attaching the starter assembly with the securing bolts (this time holding the mounts steady with a spanner)? I can’t find a torque specs for these mounts in manuals. Are they just hand-tight?

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