Cessna 150 starter question...please help!
Posted: Thu Sep 18, 2008 4:09 am
I have a Sky-tec starter kick back problem on my Cessna 150L O-200 that I would like to discuss. I am hoping the knowledgeable people on this site may give me some troubleshooting help. I have gone through quite a bit so far to try and fix this issue. In a nutshell I will get a strong kick back every ten or twenty starts that will either brake the starter shear pin or worse yet knock teeth off the crankshaft gear.
Here is some data on my current configuration:
- Upgraded Sky-tec starter with shear pin (old Sky-tec startes don't have it) Starter has been back to the factory for overhaul.
- Stock Cessna 150L key starter switch
- Stock O-200, 1500 SMOH, 4 new Millenium cylinders 500 STOH / motor runs great/ only use 100LL
- Prop is a Climb prop, max static RPM is on the upper range of allowable rpm range for this prop. Motor runs strong and smooth.
- Both Bendix mags have had their 500 hour inspection within the last 5 hours (I asked them to look for anything that could cause a kick back problem. They said they found a sticky impulse coupler and replaced some parts)
- new battery
- Replaced all crappy old ground cables with 5 or 6 new grounding cables (made by my local FBO and used on their C-150 fleet) I am starting to wonder if the grounding cables are letting this starter work too well??? The FBO added one extra cable that was not included by the factory. Yes this starter will crank this motor over pretty fast compared to the OEM starter.
- Timing set to 28 deg BTC per STC SE8675SW
- Yes my P-leds work great. I get about a 75 rpm drop from either mag switching to right then both then left.
- If you google 'impulse coupler' the first thing that comes up on google is a page called 'kickback' from Sky-tec's own page.
Is it possible that things are working too well and I am turning this motor over fast enough to not properly advance the timing during a start?
Looking around Sky-tec's web site I quickly found the following disclaimer...pretty scary if you ask me.
CAUTION
PLEASE READ THIS CAREFULLY BEFORE INSTALLING
YOUR NEW ST-2 STARTER
Make absolutely sure of the following:
__ Both magnetos are within manufacturers specified limits.
__Timing is correct and that there will not be any detonation before
Top-Dead-Center during the cranking procedure.
__P-leads correctly enable and disable the magnetos.
__‘Start Switch’ operates normally and is not intermittent.
__ Battery and aircraft electrical system are capable of handling the
surge of your new starter (approximately 250 Peak Amps).
If you have any doubts about the condition of your aircraft systems or its
compatibility with this new Sky-Tec starter, DO NOT INSTALL THIS STARTER.
Return it to your dealer for a refund.
Sky-Tec does not accept any liability or responsibility for damage to the
starter or your engine caused by kick-backs (detonation before TDC), low
battery pulsating of the engagement system, prolonged cranking cycles
causing the starter to overheat or any component failure of the starter which
might possibly cause ancillary engine damage.
Through the years Continental engine starters have had many problems. The
old ‘pull start’ systems were difficult to adjust and many gears were broken or
worn down as a result. The newer ‘key start’ systems employed a sprag clutch
that would ultimately fail. Both systems had the same results: upon starter
failure, parts and metal fragments would fall into the accessory case gear train
and oil. Many of these failures were either caused or contributed to by the
engine kicking back during the cranking cycle. Continental has redesigned
their starter to minimize the possibilities of these occurrences. Sky-Tec has
always adopted similar improvements to its Continental starter designs with
the enhanced capability of retrofitting older engines with minimal
modifications. More than 1,500 ST2 starters have been installed and are in use
by Sky-Tec customers today. Properly installed and operated, there is no
reason you shouldn’t expect the same levels of reliability, performance and
enjoyment from your ST2 starter purchase. Enjoy!
An important note from the Sky-Tec family scrap book: Please Read!
In February of the the year 2000, our own beloved Ercoupe 415C-D, N93543.s factory
OEM heavyweight pull-type Delco starter suffered damage from a kickback and the results
weren.t pretty as the ensuing engine teardown is now documented in the plane.s logbook.
Your Sky-Tec starter can break.
High-torque preignition events (kickbacks) can
and typically do damage starters. A piston
producing over 20 HP trying to make the engine
go backwards is no match for a starter producing
less than 2 HP. And the result, regardless of
starter make or manufacturer, is very often a
damaged starter and possibly even engine
damage.
To minimize your chances of kickback damage,
have your ignition system inspected and regu-
larly maintained by a qualified aircraft mechanic.
Starter damage resulting from high-torque impact
during start-up is not warrantable. If one should
occur, you should expect the starter to be damaged
and possibly even your engine as well. By install-
ing this (or any other starter), you are assuming all
responsibility for engine and starter damage due to
these impact events.
If you do not wish to be responsible for these dam-
ages, DO NOT INSTALL THE STARTER. Return it
immediately for a full refund from the dealer you
purchased it from.
Here is some data on my current configuration:
- Upgraded Sky-tec starter with shear pin (old Sky-tec startes don't have it) Starter has been back to the factory for overhaul.
- Stock Cessna 150L key starter switch
- Stock O-200, 1500 SMOH, 4 new Millenium cylinders 500 STOH / motor runs great/ only use 100LL
- Prop is a Climb prop, max static RPM is on the upper range of allowable rpm range for this prop. Motor runs strong and smooth.
- Both Bendix mags have had their 500 hour inspection within the last 5 hours (I asked them to look for anything that could cause a kick back problem. They said they found a sticky impulse coupler and replaced some parts)
- new battery
- Replaced all crappy old ground cables with 5 or 6 new grounding cables (made by my local FBO and used on their C-150 fleet) I am starting to wonder if the grounding cables are letting this starter work too well??? The FBO added one extra cable that was not included by the factory. Yes this starter will crank this motor over pretty fast compared to the OEM starter.
- Timing set to 28 deg BTC per STC SE8675SW
- Yes my P-leds work great. I get about a 75 rpm drop from either mag switching to right then both then left.
- If you google 'impulse coupler' the first thing that comes up on google is a page called 'kickback' from Sky-tec's own page.
Is it possible that things are working too well and I am turning this motor over fast enough to not properly advance the timing during a start?
Looking around Sky-tec's web site I quickly found the following disclaimer...pretty scary if you ask me.
CAUTION
PLEASE READ THIS CAREFULLY BEFORE INSTALLING
YOUR NEW ST-2 STARTER
Make absolutely sure of the following:
__ Both magnetos are within manufacturers specified limits.
__Timing is correct and that there will not be any detonation before
Top-Dead-Center during the cranking procedure.
__P-leads correctly enable and disable the magnetos.
__‘Start Switch’ operates normally and is not intermittent.
__ Battery and aircraft electrical system are capable of handling the
surge of your new starter (approximately 250 Peak Amps).
If you have any doubts about the condition of your aircraft systems or its
compatibility with this new Sky-Tec starter, DO NOT INSTALL THIS STARTER.
Return it to your dealer for a refund.
Sky-Tec does not accept any liability or responsibility for damage to the
starter or your engine caused by kick-backs (detonation before TDC), low
battery pulsating of the engagement system, prolonged cranking cycles
causing the starter to overheat or any component failure of the starter which
might possibly cause ancillary engine damage.
Through the years Continental engine starters have had many problems. The
old ‘pull start’ systems were difficult to adjust and many gears were broken or
worn down as a result. The newer ‘key start’ systems employed a sprag clutch
that would ultimately fail. Both systems had the same results: upon starter
failure, parts and metal fragments would fall into the accessory case gear train
and oil. Many of these failures were either caused or contributed to by the
engine kicking back during the cranking cycle. Continental has redesigned
their starter to minimize the possibilities of these occurrences. Sky-Tec has
always adopted similar improvements to its Continental starter designs with
the enhanced capability of retrofitting older engines with minimal
modifications. More than 1,500 ST2 starters have been installed and are in use
by Sky-Tec customers today. Properly installed and operated, there is no
reason you shouldn’t expect the same levels of reliability, performance and
enjoyment from your ST2 starter purchase. Enjoy!
An important note from the Sky-Tec family scrap book: Please Read!
In February of the the year 2000, our own beloved Ercoupe 415C-D, N93543.s factory
OEM heavyweight pull-type Delco starter suffered damage from a kickback and the results
weren.t pretty as the ensuing engine teardown is now documented in the plane.s logbook.
Your Sky-Tec starter can break.
High-torque preignition events (kickbacks) can
and typically do damage starters. A piston
producing over 20 HP trying to make the engine
go backwards is no match for a starter producing
less than 2 HP. And the result, regardless of
starter make or manufacturer, is very often a
damaged starter and possibly even engine
damage.
To minimize your chances of kickback damage,
have your ignition system inspected and regu-
larly maintained by a qualified aircraft mechanic.
Starter damage resulting from high-torque impact
during start-up is not warrantable. If one should
occur, you should expect the starter to be damaged
and possibly even your engine as well. By install-
ing this (or any other starter), you are assuming all
responsibility for engine and starter damage due to
these impact events.
If you do not wish to be responsible for these dam-
ages, DO NOT INSTALL THE STARTER. Return it
immediately for a full refund from the dealer you
purchased it from.