Zeeltronic backfire issues

[Colby]

So my ski absolutely ripped today. The only thing is it’s backfiring when I try and start it. I have 17° of start timing. I’m trying to figure out if I have too much timing or if something else is up. Once the ski is running it runs like a raped ape. Any help with curves for a 1105 or any pv motor with start timing? Thanks in advance.

 

[Harbor]

When you say backfire do you mean engine kick back during starting ?

My Zeel in on the shelf, I have my MSD’s start regard on gives me 12 degrees starting timing so it doesn’t kick back so bad

 

[Colby]

Yeah it will kind of kick back and it’s been blowing my pv boots off also.

 

[DylanS]

Yeah it will kind of kick back and it’s been blowing my pv boots off also.

Harbor is right, you’re firing your plugs too early. A buddy of mine had this exact issue with a 66e and a riva CDI/offset keyway.
Not a zeel guy but whatever you can do to retard that start timing a little would fix your issue.

 

[Harbor]

Yeah it will kind of kick back and it’s been blowing my pv boots off also.

Yes mine did that too, liquid fuel and fuel vapor would build up in the crankcase and exhaust and randomly ignite while trying to get the dang thing to crank fast enough, long enough to start and run on its own…

When it’s cold out my Lipo battery can’t crank my engine fast enough and I get the same rut rut rut type slow labored cranking that precedes the kick back and backfire, so I have to heat the battery with my trucks heater first to get her to crank fast enough to start… in cold weather

Dylan’s correct, do what you can to reduce your cranking timing, 10 or 12 degrees would be good… lipo battery needs to warm. If your issue persists your issue may be elsewhere like JC mentioned

Btw, The Epic HX3 ignition I had could not start my engine without major kick back and random backfire. No matter what I did with low RPM timing, timing offset, my timing light always showed the same starting timing…. Turns out That ignition has fixed start timing and is not adjustable, even though the software lets adjust the curve, the programmed curve is ignored until it running.. pulled my hair out on this…..so couldn’t use it on a 1200cc engine, worked good on a 8 mil 865, but would hard crank at times, usually first crank but second crank was faster and ok..

Jc, from all this, I found engine cranking speed is around 175 RPM and the enhancer start timing verified @ 12 deg….I also got the curve file from AirTime Products had contact with MSD on the enhancer curve and TL curve details..
400 RPM is faster then cranking speed, the engine is already beginning to run and the timing is at a different rpm point in the curve like you mentioned above..

 

[Harbor]

Wow, 175 rpm is a very low cranking speed for most Engines...but you do have a Custom Engine with High Compression.

Under Pump Gas Compression and a Good Strong Battery, cranking can be up to 300 RPMs.

I watched my Tachometer once while doing Cranking Compression checks and I remember seeing 400+ rpms, but that's with all the Spark Plugs out & grounded, Throttle wide-open and a Fresh Lead Acid or AGM Battery.

I'll have to read the Tach next time I start my Engine ready to ride.

Thanks for those additional details, helps me understand how you arrived at them..

 

[Jcary85]

In +/- trigger mode it uses the trailing edge for start timing. If you set to + only it will honor your low rpm settings. However, anecdotally I believe the RPM needs to be decent for zeel to get a good reading. So….. I’m planning to weld a glob on the trailing edge of both lumps and extend it 5 degrees to run more retarded start timing. If my cranking speed is low I sometimes get small backfire-ish starts as well

 

[Harbor]

So just took a Cold Start Cranking RPM reading with a PET 2100 DXR Tachometer on the Pump Gas DASA 850 with just under 180 psi Compression.

As you can see, the Starter easily hit 540 rpms with a quick push of the Start Button. On the Trailer without Water Resistance.

Didn't want to actually fire the Engine so that the highest Starter RPM reading would be preserved and not overwritten by the actual Combustion Process. So left the Spark Plugs in, the Throttle closed and grounded the Spark Plug Wires with another set of Spark Plugs.

Battery is a Lead Acid YUASA with 320 or so Cranking Amps. Read 12.54 Volts just prior to cranking.


View attachment 424628

I went and tried to do the same test.. it’s not apples to apples comparison however.. But iam glad we’re discussing this, turns out we both have valid points..
didn’t want to spin the big engine so tried My 8 mil Lamey instead @200 psi with a 16 cell Lipo @14.25 volts …. spun 890 and you can here it cranks fast..
Not sure if the tech reading is accurate though

So I tried the big engine, 1200 16 mil @225 dry, no fuel… you can hear it spins much more Labored and slower…. Dry and warm 82 deg weather the Lipo is working good.. has a brand new Mitsuba starter this time… old starter I saw 175 and after I added the new starter I rechecked cranking speed and it was 261…. today on this engine the tach was not picking up an RPM reading for like 3 try’s then it read the extact same number 261 and you can hear it’s slower the the other engine, BUT when I was looking at the video I took, I realized the tech is misreading the rpm, I suspect it’s due to multiple spark discharge… what I read as 261.0 today, but is actually 2610 not 261, now iam wondering if the 175 was 1750…. I suspect it is… the tech is misreading and I missed it originally ?

So I located my tiny tach, battery gone dead , cut it open and put a battery in it.. and redid the test on 360 degree 1 spark per revolution… now is that the correct setting with multiple spark discharge ?
The tiny tach set like that showed 732 ?

If you pm me your phone number I’ll msg you the videos and you can hear the engines crank….

 

[OtherDonnieGuy]

760 or 701 stator? Could be your issue there. If the engine is slower cranking with ignition active vs dead, I would be looking into ignition fault (I have had bad cdi and bad stators cause intermittent weak cranking, even had them "lock" the engine trying to turn over).

Other thing I would do, is let it sit for a minute or however long it takes to typically backfire, but kill the spark and crank it, then pull plugs and see if one is really wet. Could just be a simple fuel issue (leaking needle, siphon valve ect).

 

[Colby]

I definitly have a lean condition going on as well I was trying to figure out yesterday. I also set my initial timing to 12 degrees up to 1500 rpms and the ski starts way easier and didnt back fire or do anything dumb at idle or while trying to start. So im thinking i just had way too much timing while cranking causing my issue. Now i need to work on the small hang the ski has after a blip of throttle out of the water.

 

[DylanS]

I definitly have a lean condition going on as well I was trying to figure out yesterday. I also set my initial timing to 12 degrees up to 1500 rpms and the ski starts way easier and didnt back fire or do anything dumb at idle or while trying to start. So im thinking i just had way too much timing while cranking causing my issue. Now i need to work on the small hang the ski has after a blip of throttle out of the water.

I Would suggest bringing your curve up to your max timing at 1500 and have your curve start leaving 12 deg at 1k rpm before You try tuning out a condition at low throttle.

 

[Colby]

Update. My lows just needed to come out a half turn. The ski is supper crispy now with plenty of power even on this mild curve. Planning to turn timing down on initial start set it to 10 deg till 1k than ramp into my curve.