Honda Mini Tiller will not start

Rekusu

What ho one and all,

I am still having problems starting my Honda FG110 mini tiller and the issue was documented here:

https://forum.gardenersworld.com/discussion/1057936/honda-rotavator-totally-flummoxed#latest

So I have been revisiting everything that I have done.

Since the carb is the most likely cause, I bought a carb repair kit and everything has been cleaned and replaced. Nothing. Bought a complete replacement carb and still nothing.

New spark plug and ignition coil and still nothing. Checked the timing and seems perfect but that is not adjustable. Good spark, valve clearances are as the book, valves not stuck open. Dismantled and cleaned again the original, refurbed and new carbs in case drying fuel has blocked the tiny holes. Nothing.

Do not have a compression tester but with finger over the spark plug hole, there is compression but I really don't know if it is sufficient; I almost think there is insufficient compression, but what do I know?

It does occur to me that perhaps the off switch is working too well and is preventing the engine starting. I know that off switch sorta shorts the ignition pulse but does it actually kill the spark at the plug? Certainly in the run position, there is a good spark.

If it is a compression issue and the valves are closing fully, presumably the problem can be with the piston rings and /or piston itself. Can I check this without dismantling and without a compression tester?

Thanks and toodle pip

ColinA

Have you tried putting a small amount of fuel into the cylinder through the spark plug hole then trying to start?

Rekusu

Thanks fro your reply.

No, but I have giving a squirt of WD40 into the inlet side but nothing.  My feeling is one of two things; compression (or lack of it) or lack of fuel.  But the carbs have been dismantled so many times, I am now a carb dis-assembly expert, but still nothing.

As for compression, I can feel it with my finger but also, I can hold my finger over the plug hole relatively easily.  Have no idea if the compression  should resist my finger pressure or not.  Valves have been tested and they are closing fine, no stickiness.

Chris-P-Bacon

Time to get the multi-meter out & check the switches perhaps?

Dovefromabove

Afraid I can’t help … I can change the spark plugs in a Mini but that’s my limit. However I did want to say I admire your tenacity … you’ve been battling with this for six months now. 😵‍💫

Rekusu

You know when you mislay your car keys or similar, and look everywhere but they are no-where to be found.  So you look again, on the off-chance that they may suddenly appear in the same place that you looked previously.  but magic does not happen.

So I keep hoping that if I clean the carb again (and again and again) magic will happen and it will start.

I know the  whole engine is not particularly complex so am sure that the solution is on page one of the manual, turn the on/of switch to on to start!

To date, no such luck.

On the other hand, having to turn the garden with a fork is better exercise.

Chris-P-Bacon

Rekusu said:

On the other hand, having to turn the garden with a fork is better exercise.

Go "no-dig".. don't have to turn it at all then.

ColinA

If you suspect the switch simply disconnect the lead to it as to WD40 into the inlet side it will not fire up on that it needs something more volatile

Rekusu

Thanks for the suggestion.  Already done that but still nothing.  Also did a continuity test on the lead and on/off switch, and I am sure that is working fine.

Only thing left is compression and have been searching eBay for an inexpensive tester.

steephill

Have you tried stuff like Holts Bradex Easy Start spray? Squirt directly into the carb for a couple of seconds and it will start most engines. If it fires after using that then at least you know that there isn't a mechanical or electrical fault.

Rekusu

Haven't tried that but it is not a complex engine so there cannot be too many things that can go wrong.  Timing is fine and non-adjustable; I have just done a comparison compression test with my finger over the plug of my Makita leaf blower (probably a similar sized 4 stroke egirine) and I would say that the Honda feels very similar.  On the Makita, I can keep my finger over the hole during the compression stroke, as i can with the tiller.

I guess the least expensive option is to but another carb; certainly it is less expensive than £50 per hour (plus parts!) at the local stealer.