Office of Steam Logo_1

Author Topic: New M92 not running  (Read 693 times)

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
New M92 not running
« on: July 23, 2020, 09:59:12 am »
Hello all,
My new M92 engine arrived this morning put batteries and fuel in ,oiled it then in great anticipation
turned the flywheel and nothing.No spark so tried fresh batteries still nothing put voltmeter on and
only 1.4 volts on new batteries can anyone tell me why they are losing strength in 5 minutes ?.

Here's hoping
Trevor.

yozhek

  • Jr. Member
  • **
  • Posts: 207
  • Location: Somerset, England
Re: New M92 not running
« Reply #1 on: July 23, 2020, 10:09:02 am »
Hi Trevor,

I suppose it could be a short somewhere?  Did you check each individual battery? I have seen those battery holders make a bad connection sometimes...
Just guessing
Ade

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
Re: New M92 not running
« Reply #2 on: July 23, 2020, 12:15:15 pm »
Hi Ade,

Checked all 3 batteries ,all the same at 1.4 volts after 5 mins

Cheers Trevor

yozhek

  • Jr. Member
  • **
  • Posts: 207
  • Location: Somerset, England
Re: New M92 not running
« Reply #3 on: July 23, 2020, 12:27:30 pm »
Hi Trevor,

Nothing worse than getting something new and it is faulty  :'(

So the combined voltage at the battery holder plug should be 4.2 volts offload, and when plugged into the ignition and turned on i would guess you would be looking at 3.8 volts?  If the voltage is lower check the obvious like reversed connector etc. also check the power on the other side of the switch in case the switch is duff.

Maybe the batteries are not so good, but 1.4 volts is not far off the mark, it is the on load voltage that counts, anything over 3 volts should be fine.

How about the hall effect sensor, no pinched wires? disk on the right way around (air gap not too big).

Banggood sell replacement ignitions for about £35 but i guess if all looks ok it should go back under warrentee.

Ade

Particleman

  • Newbie
  • *
  • Posts: 19
Re: New M92 not running
« Reply #4 on: July 23, 2020, 01:26:00 pm »
Silly question but... I have read that the on and off switch can be installed in either direction have you checked the switch with a voltmeter? Also have you examined the spark plug lead wire?

RedRyder

  • Administrator
  • Hero Member
  • *****
  • Posts: 2219
  • Location: Connecticut - USA
Re: New M92 not running
« Reply #5 on: July 23, 2020, 02:09:16 pm »
  • I would suggest brand new batteries. New AA batteries are not at 1.4v.
  • They are typically 1.6v or a hair more.
  • Also, check the spark plug lead and make certain it has some wire exposed in the plug boot and that it is pushed in far enough.
  • Then take the plug out, put the boot back on and hold it up to a head bolt turn it on and spin it over.
  • You should see a nice blue arc from the plug electrode.
  • Also use this time to check that it is firing at top dead center on the compression stroke. If it isn't, fix that now.
  • There really isn't that much that can go wrong. Of course also make certain the batteries are in the correct position.
  • I think you might also unplug the battery holder and test the voltage at the plug. You should be starting there with around 4.8v.
If it remains bad, ask Jin for a refund or replacement. He is good about standing behind his products.
Please let us know.


Gil

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
Re: New M92 not running
« Reply #6 on: July 24, 2020, 04:39:46 am »
Thanks for the suggestions,i've tried them all but still no spark.

Have pm'd Jin and he's going to send some ignition accessories over so hopefully
that should sort it out, will let you know when i get them.

Thanks again,

Trevor.

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
Re: New M92 not running
« Reply #7 on: August 10, 2020, 05:40:59 am »
Well the new ignition parts arrived and were fitted ,thanks Jin , the engine ran but very fast, all the timings have been
re-checked and seem ok, came to start the engine a couple of days ago and the compression has gone, taken the
head off to see if valves were sticking but there ok so any ideas as to what my problem is now would be appreciated.
When turning the flywheels i noticed that air is being blown out of the carb does this suggest anything ?.
Thanks Trevor.

yozhek

  • Jr. Member
  • **
  • Posts: 207
  • Location: Somerset, England
Re: New M92 not running
« Reply #8 on: August 10, 2020, 05:58:53 am »
Hi Trevor,
Glad you got the ignition parts.
As it is an atmosperic inlet then it has to be poor seating, probably a speck or swarf or dirt.
You can check the valves with the head off buy pouring some petrol or rubbing alcohol into the port and if it leaks past the valve then it needs attention.
Hope this helps
Ade

RedRyder

  • Administrator
  • Hero Member
  • *****
  • Posts: 2219
  • Location: Connecticut - USA
Re: New M92 not running
« Reply #9 on: August 10, 2020, 07:24:08 am »
Hi Trevor,
Glad you got the ignition parts.
As it is an atmosperic inlet then it has to be poor seating, probably a speck or swarf or dirt.
You can check the valves with the head off buy pouring some petrol or rubbing alcohol into the port and if it leaks past the valve then it needs attention.
Hope this helps
Ade


Good tip, Ade. Thank you!

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
Re: New M92 not running
« Reply #10 on: August 12, 2020, 02:10:15 pm »
Have tried Ade's idea of pouring down the port no sign of any leakage.

Compression came back and tried to run engine, it ran for about 5 seconds and lost compression again.

Every time the compression comes back it does the same, any ideas folks ?

Have sent an email to Jin but so far no reply.

Here's hoping Trevor.

Particleman

  • Newbie
  • *
  • Posts: 19
Re: New M92 not running
« Reply #11 on: August 12, 2020, 03:36:28 pm »
I don't have a m92 but I had some eratic compression issues  with my m94. After I stained & cleared my box the increased thickness was preventing the mechanism from completely closing the exhaust. Perhaps you can insure the mechanism is allowing exhaust to fully close.


yozhek

  • Jr. Member
  • **
  • Posts: 207
  • Location: Somerset, England
Re: New M92 not running
« Reply #12 on: August 12, 2020, 04:13:20 pm »
Hi Trevor,

My M90 would do this regularly, i would hold the exhaust valve open and blow throught the carb with the airline to shift any dirt, or sometimes pushing the valve open and letting it snap shut a couple of times would do the trick.  Those valve springs are so soft that any resistance will stop the valve seating.
Make sure the valve stem is lubricated with some thin oil too if you have not already.

In the end i went with a slightly stiffer inlet valve spring, the engine ran so much better but sometimes when starting the exhaust valve would suck open instead of the inlet, stiffer exhaust valve spring fixed that and the engine made so much better power under load and generally ran much more constantly.

Hope this helps
Ade

eec1910

  • Newbie
  • *
  • Posts: 48
  • Location: leeds england
Re: New M92 not running
« Reply #13 on: August 12, 2020, 04:29:29 pm »
Hello to Partcleman, have already altered the exhaust rocker by one turn so it closes just.

Ade will try your suggestion of heavier springs and see what happens.

Thanks for your help,

Trevor.

RedRyder

  • Administrator
  • Hero Member
  • *****
  • Posts: 2219
  • Location: Connecticut - USA
Re: New M92 not running
« Reply #14 on: August 12, 2020, 05:39:13 pm »
There is 6 to 8/1000ths exhaust valve lash clearance.  This is not much but is clearly there and I would say necessary.


Gil

 

September EOTM Winner:

Trevor’s "Bassett-Lowke Steam Generating Plant c1934"