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Root cause for Cold weather starting woes?

  • Peter Dikeman
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6 days 11 hours ago #17740 by Peter Dikeman
Peter Dikeman created the topic: Root cause for Cold weather starting woes?
I've been having problems starting my 914F3 engine (vintage 1998, now 600 hrs smoh) at temps below about 45 degrees, just a little warmer and it starts right up. i was quite amused to see that the 914F3 engine cold weather starting spec listed in my 1998 operators manual is MINUS 15F :)

I am almost certain that it's an issue of "no spark" at less than 90 RPM as the neon bulb ignition tester does not light up in these cases. I suspect i have multiple small problems contributing to my woes: old starter, old ignition modules, 10w-40 instead of 5w-40 oil, plug gaps too wide and a two year old battery.


The cheap fixes - AGM battery with high CCA , plugs, 5W oil will probably improve things, but i got to wondering what happens when i'm out in the middle of nowhere and it's 20F(or colder!!) and i can't get 90 RPM for Spark?

>> Seems to me the root problem of cold starts is "no viable spark" at less than 90 RPM.due to charging coils not really supplying enough energy to ignition modules <<

Does that make sense to those of you who know more?

If so, then while an HD starter ( and maybe new ignition modules) would probably help a lot , but those ain't cheap fixes and in the case of the HD starter doesn't really DIRECTLY address the "root cause"

I got to thinking about this and wondered if anybody has ever tried/thought of supplying the equivalent of (>90 RPM) charging coil pulses to one(or both) of the ignition modules during engine start.

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6 days 10 hours ago #17741 by Ken Ryan
Ken Ryan replied the topic: Root cause for Cold weather starting woes?
Some things that might make your engine spin faster during starts:

1. Lithium battery
2. Larger cables (4AWG) in the starting circuit
3. Solid crimps in the starting circuit
4. Clean, tight connections in the starting circuit

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6 days 8 hours ago #17742 by Roger Lee
Roger Lee replied the topic: Root cause for Cold weather starting woes?
The gold colored higher torque starter does make a big difference. I had a plane many years ago that had you same symptoms and the new starter was the ticket.
If you live in cold country I would also install a Tanis engine pre-heater and have the engine up in the 70F - 80F range along with the oil for easy starts.

Use a narrow vs wide plug gap will help. Making sure the carbs are well synced. A good battery.

A cold engine and the old starter are your two big problems. Carb sync and battery are easy to fix.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

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6 days 6 hours ago #17745 by Peter Dikeman
Peter Dikeman replied the topic: Root cause for Cold weather starting woes?
Ken, some good thoughts to add to the list of little things that eventually add up!

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6 days 6 hours ago #17747 by Peter Dikeman
Peter Dikeman replied the topic: Root cause for Cold weather starting woes?
Roger,

Trying the narrower gaps (.6mm) tonight we'll see how it goes.

Good to know starter makes a big difference , Maybe Santa will bring me a new starter :)

Do you have any comments regarding the reasons for no spark at less than 90 RPM@ prop....is it likely lack of energy from charging coil?

Peter

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