MF50 Unknown Ignition Shutdown

SaveMy50

Member
Gas engine, was running, then just shutoff for no apparent reason. Now won't start. I immediately checked fuel bowl, but it was full, so don't think gas issue. I just changed spark plugs, condenser, rotor, cap, but not points (new didn't fit, but old is gapped and sparking).

Coil? Regulator? Ignition Switch?

This happened a few years ago, but don't recall it after I changed ignition key switch a year ago. But am i missing something?
 
First of all. eliminate the regulator, it's not part of the ignition system. Pull your coil wire from the distributor cap, hold it about
an eight of an inch from the block, crank it, and see if you have a good blue spark. Did you replace the ignition parts prior to this
failure, or after?
 
Regulator was a question cause I thought that feeds ignition switch, but I ll confirm.

Haven t changed any parts since this recent shutdown issue.

Earlier Spring Maintenance:
- Carburetor Kit, set 1 turns for Throttle and Power Needles
- Spark plugs/wires changed
Ran one day, then next day it wouldn t fully fire, so:
- Cleaned up generator and replaced tensioner bolt (was stripped so was some belt slippage)
- Drained and replaced fuel, as tractor was sitting for 8 months
- Reopened carburetor to ensure no pluggage, set to 1 turns both needles, confirmed fuel line flow good to carburetor
- Replaced coil ground (?) line to distributor
- Replaced condenser, rotor, distributor cap, checked points gap at 0.20, confirmed TDC, confirmed spark at spark plugs
- Confirmed battery 12.75 V (didn t have time to confirm generator output when it started)
It fired up, with a choke, idled but didn t respond much to throttle, so adjusted power needle out turn, response way better, but minimal visual movement of governor linkage or throttle lever at carb

Drove 50 yards and it died (I immediately looked at fuel bowl but it was full). It wouldn t restart after a few tries, but that electrical style shutdown was a reminder of a couple years ago, as I noted above.

I plan to replace coil, but don t have much more insight. Can't say I like shocking myself with that coil check, but I will try.

Thanks
 
Check for spark at the coil them at each of the plug wires. You should have a strong spark at all of these points. Check for voltage going into the coil? Run a jumper wire to the coil to make sure you don't have power loss to it while cranking. Having fuel in the sediment bowl does not mean it is getting in the carb. Pull the drain plug out of the carb and check fuel flow through it. Let us know what you find.

Steven
 
try another condenser from another supplier. cheap and easy. just cause new does not guarantee it works. I recently bought a new fuel pump my craftsman 2 mower, said pump did NOT pump. replaced it and off we went.
 
Sounds like the little filter at the inlet to carb is stopped up. Running better with main jet more open is a fuel issue. Turn off gas at tank, unscrew carb drain and drain fuel out then check fuel flow with drain open.
 
I did check and got good fuel flow to the carb, but will check through drain as noted.

I will also try a different condenser, hopefully I find a meter (analog not digital) to check it as well.

As for ignition switch, which I replaced a couple years ago, is there any harm in bypassing it (direct from solenoid/battery connector) while I am troubleshooting? I can always shutdown by choking the carb.
 
Sounds like you have done plenty of work to it, much of it may be good things to do, but not necessary.
The first thing I'd do is check to see if you have spark or not. I don't read anywhere whether or not you have confirmed whether or not you actually have spark.
To test the coil, measure the resistance of the primary side and of the secondary side. The primary side should read close to a short, the secondary side, 700 to 1000 ohms. No shocks involved.
 
New Coil, points, condenser, new wires from Regulator to Battery and to Ignition Key Switch. Got good fuel flow from carb drain.

It fired up after a couple tries, ran for a bit, slow response to throttle, then it died, no effect with choke or throttle as it died.

Checked battery and coil voltage and found it dropped from 12.7 to 12.5, before I retried starting (assumed starter draw, and generator not enough time to charge).

It barely started for 10 seconds, then not again. Bypassed air filter (opened at Carb, mini bit of gas) but no change.


Questions:
- Carb initial set up, book says 1 turn throttle and power needles, my mechanic did 1.5, and cannot find what throttle screw should be set at
- Should A & F show conductivity across generator connectors and on regulator
- Should Governor be so tight as to minimize throttle lever action at carb to 1/16" play (didn't check while running, but it did respond then)
 
If the hand throttle is set to anything more than an idle, the throttle lever to the carburetor should be fairly easy to move while it's not running. The governor, once running should bring the engine up to operating RPM, set by the hand throttle, very quickly then close the throttle plate on the carb to prevent over revving.

I do not suspect you have a governor issue, it should still run even with governor issues, just not regulate RPM properly.

Carb settings are merely a guideline and everything should be fine tuned after running and warmed up. But again, if you're close it should run. Even if you are getting proper fuel flow to the carburetor, there could still be a small piece of dirt obstructing fuel flow. One of my Z134s is kind of temperamental after it's been sitting for a long period of time. I will usually give a couple squirts of starting fluid and it's enough to get it to start and continue running. Sometimes it'll need an extra squirt or two before the fuel is flowing properly.
Your battery voltage would seem to be ok. A drop from 12.7 to 12.5 would not concern me.
I think, if you haven't got it figured out already, we need to determine if your problem is in fact fuel or ignition. Sometimes it can be hard to figure out.
 
Pretty sure the shutdown has to do with governor linkage. As noted, it is very tight, not moveable with engine off.

Disconnected throttle lever from governor and it started up ok with a bit of choke, warmed up fine and sounded smooth and powerful. Almost shutdown when slowed rpm, prob cause idle screw not set, but managed to keep it running (kinda hard solo).

Cleaned up governor linkage but it's still very tight. Does that mean I have to work thru linkage reset (i.e., Adjusting the Governor and Throttle Linkage of your Ferguson Tractor on the web)

Having a similar governor question with my 35 (see 35 power loss post, but that tractor runs at least)
 
With the tractor not running, I believe you should be able to move the throttle past idle position and you should be able to move the linkage fairly easily, almost to the point of it feeling floppy. If it's tight and binding, it will not work properly. Instead of doing the adjustment, I would take some of the linkages apart and try to identify the tight spot and get it moving smoothly.
 
So disconnected the Governor Lever from the Throttle Plunger by removing the Governor Spring, and found the Governor Lever jammed and not moveable. (rest of throttle controls appeared to move fine)

Then removed the Bumper Screw, but still no Lever movement.

Does that mean the internal Bumper Spring or Lever Assembly is the problem, and the Governor has to be opened up (front disassembly)?
 
So working on removing and replacing the governor.

Removed body tin, air filter, radiator, and fan.

Now the crank pulley nut is 1 5/16, so will try to fit a socket and impact wrench on it, but it's tight and may have to use wrench instead. Any recommendation on holding flywheel without damaging? I read some have used wrench on nut and crank starter to get nut off, but will that damage anything?

Thanks for any ideas
 

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