Office of Steam Logo_1

Author Topic: M90 - horizontal engine. No ignition.  (Read 374 times)

tony1951

  • Newbie
  • *
  • Posts: 24
M90 - horizontal engine. No ignition.
« on: October 20, 2020, 11:51:05 am »
Hi.

I bought one of the Eachine Chinese horizontal hit n miss engines and found it ran well right out of the box. I ran it on lighter fuel and on ordinary petrol/gasoline with a little 2 stroke oil and manually oiled the moving parts aside from the cylinder bore.

The thing ran faultlessly off and on for demos, running maybe ten minutes at a time. It started very easily just needing a flip of the wrist, after priming with fuel by covering the air intake ad turning the engine over  a couple of cycles and then gently holding down the inlet valve a little while spinning the crank a couple of turns. I could just about guarantee that it would fire first flick after that......

Now it won't run at all. I have changed to fresh fuel, checked the mixture screw, changed the batteries for known good (measured voltage). I have good compression and the timing is undisturbed. I did a visual check on when the little flywheel magnet comes to the Hall Effect sensor and it looks like it is there at TDC on the compression stroke, or thereabouts and the disk which holds the magnet for the sensor has not been disturbed and is nice and tight.

The exhaust tappet has the correct clearance.

The spark is not that great. A little thin I would call it and there is some carbon on the nose of the plug, but I have cleaned it up somewhat with an old toothbrush and dish wash soap - then rinsed and dried it. The spark is there, but like I say not that strong. I'm wondering if the spark fails under compression - this can happen in a full size engine I know. If I test for  spark just with the bare HT lead held near the grounded parts, I get a spark, but not great.

Is there any history of the second generation engines having bad spark units? I know the earlier ones had badly wired - no earth ht units which failed all the time, probably because the ht earth return may have been going back through the hall effect sensor.

All wiring is correct and undamaged and terminals are suitably tight.

I would appreciate any advice and experience of solving problems with this engine that any of you have had. I am not inexperienced with trouble shooting full size engines so I think I have checked all the obvious pitfalls.

Nick

  • Administrator
  • Engineer
  • *****
  • Posts: 8116
  • Location: Minnesota, USA
Welcome to the forum, we have a few here that know these engines pretty well now and will probably be able to help you out...
Nick

tony1951

  • Newbie
  • *
  • Posts: 24
Thanks Nick for the welcome.

I am now certain that the issue is with the sealed electronic ignition box.

All wiring is correct and secure, the cleaned spark plug is not shorting out and the issue has developed since the engine first stopped running. The spark, such as it was got weaker and has now stopped altogether. I am going to make a new ignition unit myself using Jan Ridders idea of using a cheap sparking gas lighter unit. These are very cheap and he uses them on all of his petrol engines. I have already sent for a handful of electronic components which are needed to alter the gas lighter unit.I will be using a thyristor to switch the LT current in the coil. It will take the place of contact points in a traditional old fashioned ignition system and I am hoping that the little magnetic sensor on the engine as supplied, is a simple reed switch. If not, I have some of them anyway so can substitute if need be. (**) I suppose the whole thing will cost about £12 so - way cheaper than trying to source another unit from China and far quicker - -  - if all goes well, that is. Also - if this new one gives up the ghost, I can make another for little money.   ;D

** EDIT  12 HOURS LATER

- I checked this morning with a multimeter. The position adjustable, black sensor which triggers the spark on the engine at the flywheel as supplied,  is indeed a reed switch. It is naturally open circuit and closes when the neodymium magnet comes in close proximity. I am pretty sure that will work to trigger the spark on the Jan Ridders circuit, just as it did on the original design. 

Here is a link to Jan Ridders page on the circuit. Click for English version of the page unless you read Dutch:

http://www.ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_crcuit_frameset.htm

tony1951

  • Newbie
  • *
  • Posts: 24
Re: M90 - horizontal engine. No ignition.
« Reply #3 on: October 23, 2020, 11:30:23 am »
Got it running again with an adapted gas stove igniter as an electronic ignition system. Incredibly easy fix, lower voltage system, but starts right away. I have not even replaced some of the bits advised by Jan Ridders, the originator of the idea. The 400v capacitor I still require is expected in tomorrow's post.

Quite pleased with this and the total cost of the gas stove lighter was £7 and a few pennies for a capacitor and an extra resistor is all I actually needed. The spark is triggered by the reed switch which came with the unit - the little black box down by the fly wheel.

 ;D

I can't figure out how to upload a video so I can't show you how well it works. Sorry.

Stoker

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3618
  • Wherever you go ......... there you are!
  • Location: Eastern Sierra
Re: M90 - horizontal engine. No ignition.
« Reply #4 on: October 23, 2020, 12:17:57 pm »
Very interesting retro-fit of relatively simple electronics. Thanks for the link to Jan's web page on this concept, it could come in handy for many of us someday!
"Information is not knowledge, Knowledge is not wisdom, Wisdom is not truth, Truth is not beauty, Beauty is not love, Love is not music: Music is THE BEST...   
Wisdom is the domain of the Wis (which is extinct). Beauty is a French phonetic corruption of a short cloth neck ornament currently in resurgence..."
F. Zappa ... by way of Mary, the girl from the bus.

tony1951

  • Newbie
  • *
  • Posts: 24
Re: M90 - horizontal engine. No ignition.
« Reply #5 on: October 23, 2020, 01:23:39 pm »
Thanks Stoker.

I've been struggling to upload a video, but seem to have got it now. Here is the engine running on the lash up igntion system. It is not finished yet and needs a 400v capacitor to replace the 100v one the spark stove ignitor came me with. Nevertheless it is working as you see and I think it is very easy to start up. The new capacitor will come tomorrow I think and I will also properly insulate the high tesnion parts, especially the coil because they may spark over and develop a tracking failure like I suspect killed the original unit.


deverett

  • Newbie
  • *
  • Posts: 1
Re: M90 - horizontal engine. No ignition.
« Reply #6 on: June 26, 2022, 09:37:32 am »
In case anyone has ignition problems with an Eachine type engine...

I've had one of the M90 engines for a while and it has run really well.  I took the engine off the box to check a few things and didn't notice the earth wire had become detached when I tried to start it.  Result: fried Hall sensor.

Except that the sensor is not a Hall, but a glass reed switch and was still good.  The fried component is in the module box.
Is there a way to get into the box of tricks to be able to get at the components?  If not, another $55 for a new ignition module.

Dave
The Emerald Isle