912 engine preheater

[jiott]

Herman, leaving the heater on continually would concern me about an electrical malfunction and fire. In your mild climate just plug in the strip heaters when you get to the hangar and I'll bet that in 1/2 hour (about the time it takes to do your pre-flight and prepare to fly) it will be warm enough to start easily. I use a cheap "milk-house" heater whenever it is 40F or below and one hour of heating is plenty for me (my engine 912uls has the soft-start).

[herman pahls]

Thanks for the responses.

The start procedure I use includes turning on the electric pump to make sure it is making pressure and to fill the float bowls if needed.
I then pull the enrichener with the throttle fully closed and turn over the engine with the ignition off for 5 seconds.
Then I wait 15 seconds, advance the throttle to a fast idle, engage the starter and then flip both mag switches to give the starter a head start on the mags.
In warmer weather this works almost flawlessly.
Go camping at altitude in the Idaho Backcountry where it often gets near freezing at night in June and you sometimes wonder if the starter or sprague will destroy themselves before it starts.
Once started that day it fires off perfectly.

Larry, the enrichener seems to getting plenty fuel into the venturi without enrichening with the electric fuel pump on.
I have learned that too much enrichener and it will act flooded when it finally starts.
I wish I had your updatedignition system even though your engine starts fine with out the soft start feature.

Lowell, ever since you gave me the starting routine, it starts great in warm weather but not cold.

Jim, I also am concerned about the power constantly on for fear of fire.
in the past it was common procedure to leave a 100 watt bulb going inside the aircraft to keep the avionics warm.
I am sure the 100 watt bulb is safer than heat strips.
Maybe using a low amperage circuit breaker than the traditional 20 amp would add some safety in case of a short develops.
I will experiment, but doubt a 1/2 hour will do much.
Reiff, the company that makes the pre heaters suggests 3 hours to get 20 degrees temp increase with their 150 watt system and I am only using 100 watts at the time.
They say these lithium batteries actually crank better if you place a load on them for a few seconds and then wait several seconds.
Seldom does it freeze here but it sure has the last few weeks.

I may fly several times a week but for only 30-45 minutes.
So having an engine that starts simply and does not feel like it is destroying itself makes it a more enjoyable process.
Maybe I have a problematic starting older 100 hp but it sure runs well once started.
I am hoping pilots with similar high compression engines would have the answers.
My goal is to install the Big bore Hi compression kit which will only make the starting more difficult.

Herman

[Norm]

This has morphed into a starting sequence procedure so I have a newbie question.

Does anyone use a primer on the 912. I am fairly new to 912 operation and I know when I put a primer on my 582 the starting was much easier. Would this work on the bings on the 912 as well as it does on the 582?

[SkySteve]

Norm,
I have an 80hp 912. I did install a primer and use it for all "first starts" of the day regardless of temps. I prime 5 or 6 pumps, do not use the enricher, pull the throttle out about 1/4", switch mags on and turn the key. It starts every time. Our temps range between 100 F and -20F but I don't fly below about 25F. I do not have an engine heater. My plane is always hangared.

[Norm]

Thanks Steve Think I will do the same.

[jiott]

Herman, you might give my "milkhouse" heater system a try. It is 1500 watts, quite a bit more than the 150 watt block strip heaters. A half hour at 1500 watts may do more than you think. I realize that all 1500 watts of hot air is not going into the block, but still it is quite a bit of heat circulating thru the engine compartment.

[herman pahls]

I have done more experimenting with engine preheating using Kats engine block heating strips from Amazon and have settled on the best combination for my application.
Jim.

I am too impatient to wait for a heater even if it only took only a 1/2 hour before flight.

These self adhesive strips are 2" x 5", produce 50 watts each and cost $18 each.
I started with 2 strips on the bottom of the 912ULS and 1 on the oil tank.
This gave 112 degrees oil temp before start up and the 912 starts and idled like I had just turned it off.
I cover the cowl with a quilt and it feels almost too warm.

I disconnected one of the engine heaters and the cowl felt noticeably less warm and the oil temp read 96 degrees before start up and it started perfect.

Then I disconnected the oil tank heater and the next day the cowl felt barely warm with only one block heater, the oil temp was 76 degrees and it was hard to start. Just like it is when I do not preheat.
Hard to start to me means the starter acts like it is up against a wall and it takes several attempts to start.

I went back to 2 heaters and am making a dedicated extension cord to power these strips that add up to 100 watts.
The extension cord will have a 3 amp fuse on the hot leg of the cord.
If I am doing the math correctly, 100 watts only requires about 1 amp of current so I am going to a low amp fuse to reduce the chance of fire if there were to be a short.

I especially like the fact that the engine gets up to take off temperature in 2 minutes instead of 10 or more and we had a rare snow here today.
I can use a cell phone activated switch if I pre plan a flight by 6 hours instead of leaving the heaters on full time.
Herman