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912 SMD Soft start ignitions

  • William Campbell
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2 years 10 months ago #9236 by William Campbell
William Campbell created the topic: 912 SMD Soft start ignitions
I just received 'two' new SMD 'advance soft start modules' for my 912 rotax engine. I had the 2006-2007 modules where both ignitions were failing on start up unless they were heated with a heat gun.

Does anyone have the instructions or a reference where I can look up to find out where to install the extra lead in the soft start plug that is to be connected to the starter switch? Also, where is the lead to be attached to the starter switch? Any help would be appreciated as I do not want to damage these modules as I waited over two months to get them. One final question: can both soft start modules be hooked up as soft starts to enable starting on both ignitions?

William Campbell
Fresno, CA

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2 years 10 months ago - 2 years 10 months ago #9238 by Roger Lee
Roger Lee replied the topic: 912 SMD Soft start ignitions
Hi William,

This should be fairly easy for you to do. On the 6 pin connector there is one hole left open on each module in a corner. Put a wire in there on each module and run it down to the starter relay. The starter relay has three wires. One large on on the left and one large one on the right. Then it has a small spade connection with a wire in the middle. Run those two wires from the modules and connect those two to the existing small centered wire on the starter relay. That's all there is to it. When the starter relay is given power these two new wires to the modules will initiate the soft start feature. To get full advantage of the soft start system you would also need to replace the flywheel.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last Edit: 2 years 10 months ago by Roger Lee.
The following user(s) said Thank You: William Campbell

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2 years 10 months ago - 2 years 10 months ago #9240 by Rob Seaton
Rob Seaton replied the topic: 912 SMD Soft start ignitions
Here is some more information.
Just to clarify:
-The wires should be connected to the starter relay, not the starter.
-The wires connect to the BOTTOM six-pin connectors; they connect to the coils. see page 2 of attachment.
-Take a good look at how the connectors un-latch before you rip them apart.
-The rubber seals in the connectors will be stuck, just wiggle and gently pull at the same time and it will come apart.

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Last Edit: 2 years 10 months ago by Rob Seaton.

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2 years 10 months ago #9241 by William Campbell
William Campbell replied the topic: 912 SMD Soft start ignitions
Hi Rob,
You fellows on this site are priceless. Thanks for the attachment and information on how to loosen the 6 pin connectors. I am familiar with how the lock works on the connectors as I have removed the 'A' module and replaced it with a loner to get the engine running while waiting on the new modules.

Many thanks,

Bill

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2 years 10 months ago #9242 by Roger Lee
Roger Lee replied the topic: 912 SMD Soft start ignitions
Hi Rob,

Thanks for catching the starter verses starter relay comment. I was typing and should have done a better job of reading what I wrote. I fixed it in my post.
I was in too big a hurry to leave for an appointment.

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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2 years 10 months ago #9301 by William Campbell
William Campbell replied the topic: 912 SMD Soft start ignitions
This is Bill Campbell in Fresno. The new Soft Start ignitions have been installed in my 80hp 912UL with both ignitions connected for the soft start feature. The engine starts, runs very well and seems to have a much stronger ignition on start. Again thanks to everyone who got me through the installation phase.

Now I have another problem. The engine is the 80hp 912UL and has a three blade warp drive prop. In the past there has been a slight resonance of the prop when starting. This engine does not have slipper clutch. Now with the new ignitions it is very pronounced resonance and difficult to overcome. It is a damaging shake until it settles out. I am looking for some starting technique that may minimize this.

My thoughts:
1. Crank the engine with the ignitions 'OFF' for a second or two. Advance the throttle a bit and try to start it and see if it will spin up through the resonance.
2. Disconnect the soft start wires and see if that changes it.
3. Have a slipper clutch installed
4. Heavier prop.

Suggestions,
Shaking in Fresno,

Bill

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2 years 10 months ago #9303 by Roger Lee
Roger Lee replied the topic: 912 SMD Soft start ignitions
Hi William,

When using the soft start modules the engine now starts after top dead center verses before top dead center. The starter circuit stays in that mode for approx. 6 seconds. It runs rough during this time period. At that point the the timing changes. Is this the vibration you are referring to?

If it is that is normal for all soft start systems.

_______________________________________________________________________________________________________
You already have one of the heaviest props and that could be part of the problem. How long is this prop? Hopefully no more than 68" and no nickle edges. You really don't want a real heavy prop. If anything you would want to go lighter.
This may or may not be a prop issue, but if it isn't the normal soft start roughness then you can try these.
Make sure the pitch in each blade is identical, make sure the blades are tracking equally, get a dynamic balance, make sure your rubber engine mounts aren't more than 5 years old (replace them if they are), Make sure the engine mounts bolts are torqued up to proper spec. Make sure the carbs are synced.

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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2 years 10 months ago #9398 by William Campbell
William Campbell replied the topic: 912 SMD Soft start ignitions
Hi Roger,

Thank you for your input.

It is not that the engine is running rough. It is the prop kicking back and forth against the gear box dogs in this non-slipper clutch engine during start up. It is actually hard to increase the RPM's while this is going on. With the new soft start ignitions it seems, as you suggested, to have aggravated the problem. I have found a starting procedure that has virtually eliminated the problem.

1. Crank the engine for a second or two with the ignitions off, Throttle Closed and full choke.
2. Set throttle about 1/8" from Closed, both ignitions on, full choke. The engine starts and easily spins up to about 2200 RPM and stops the prop from kicking back and forth against the gear box dogs.

This starting procedure seems to be the best for this 80HP engine.

Again thanks for your input,

Bill Campbell
Fresno, CA.

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2 years 10 months ago - 2 years 10 months ago #9401 by Roger Lee
Roger Lee replied the topic: 912 SMD Soft start ignitions
So the engine starts right up,but after the start the prop kicks back and forth for a few moments?


This may be caused by a gearbox issue and maybe it should come off and be inspected, possibly an ignition issue?

This may be aggravated by a start procedure like flooding, gearbox needing maint, too heavy a prop, carb sync adding to an existing issue? I'm not sure, but would check them all.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last Edit: 2 years 10 months ago by Roger Lee.

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1 week 3 days ago #16976 by Jaime Baksht
Jaime Baksht replied the topic: 912 SMD Soft start ignitions
Hi I'm going to replace 966726 SDM for a 965444 soft start module
Is posible to conect the new module in the soft start configuration and de 966726 in the normal conexión?

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1 week 2 days ago #16984 by Roger Lee
Roger Lee replied the topic: 912 SMD Soft start ignitions
Hi Jaime,

If I understand you correctly you want to put one soft start module and one standard ignition module on?
If that's what you mean then I would make them both the same. If you do buy both soft start modules and want to only hook one up I would hook both up.

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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