Mountfield R28M Ride-on-Mower Mistake? Any tips..?

Section62

ThisIsWeird said:

If you take photos of all 4 sides of that engine and post them on here, one will likely have the plug in it.

You can see it in the second picture above.  With a modern single-cylinder engine the spark plug is almost always somewhere around the opposite end to the crankshaft.

sujsuj

4 photos from all sides attached.. where is spark plug ? Is this on 2 LHS pic with OHV written on it..? Thanks


so

born_again

At a guess Spark Plug in under the black box (1 front on it) on top of the engine. 
Your handbook should tell you exactly where it is, as it's a serviceable item.

Just be careful removing & replacing spark plug or you will strip the thread. If you really are not sure, take it to a dealer to service. While not really MSE, the amount of damage & cost to repair if done wrong will make it MSE friendly. 👍

molerat

In your pic 2LHS the silver right angled thing on the left is the spark plug cap.  Pull that off and you will see the plug.

markin

Should be easy to find the manual for a stiga 350.

As for the blades could the nut be a reverse thread, so clockwise to undo?

ThisIsWeird

Hi SS.

It's as Mole says.

The plug enters the cylinder head at an angle. The plug cap is a pull-off, push-on fit, and should be pulled straight off in the direction the plug sits - see orange arrow. Give it a few small rotary back-and-forth movements first, to 'break' any seal formed over time. Then pull it firmly off, again wiggling it a bit if needed.

The cap has a black cable going to it - see red arrow. There will be enough 'slack' in that cable to allow the cap to pull right off, but probably not much more. See how the black casing has a cut-out in it to allow this movement from the cable?

You'll then see the actual plug, and I hope you know what that should look like? If not, start Googling...

The exposed part of the plug consists of a ceramic insulator - usually white - with the metal connector on the top. To get to the nut, you'll almost certainly need a proper plug socket which has this extra length, and often a rubber sleeve inside to protect the brittle ceramic part - do you have a socket set with one of them in it?

Undo anti-clockwise as normal. It might be stuck after such a long time, so you will need to be firm with it. Try not to allow the socket to wobble sideways as you do this, tho', as you'll risk snapping the ceramic plug shaft; it isn't 'weak' as such, but it is brittle. 

Once out, place a cloth bunched up in front of the plug hole, and spin the engine (hopefully it'll now spin...) for a good few seconds at a time. See if oil is ejected.

I'd suggest a new plug.

Section62

ThisIsWeird said:

Undo anti-clockwise as normal. It might be stuck after such a long time, so you will need to be firm with it. Try not to allow the socket to wobble sideways as you do this, tho', as you'll risk snapping the ceramic plug shaft; it isn't 'weak' as such, but it is brittle. 

Being 'firm' with a spark plug stuck in an alloy cylinder head is a bad idea.  There's a high risk of stripping the thread out of the cylinder head and needing to replace it (an expensive job).  An experienced technician will have a feel for a safe level of 'firmness', but if you've never changed a spark plug before it is difficult to judge what is a safe level of force.

There are ways of extracting a stuck spark plug with lower risk, but these aren't really appropriate for a novice DIYer.

If the plug is being replaced with a new one (a good idea) there's less need to be concerned about damaging the ceramic.  The focus should be on removing the plug without damaging the cylinder head.

Before doing anything else DIY related with this mower, the OP might want to note the cost of a replacement engine for this mower is £605 RRP.  Getting it serviced properly by a local independent should cost a lot less than that.

subjecttocontract

The last time I made the mistake of tipping up my mower, the problem was that engine oil had got into the paper air filter. I just removed the fi!ter, cleaned up any excess oil, left it to stand for a while, fitted a new filter and started the mower. There was lots of smoke as oil had gone into the carburretor etc but after a few minutes it burnt off and ran normally.

ThisIsWeird

subjecttocontract said:

The last time I made the mistake of tipping up my mower, the problem was that engine oil had got into the paper air filter. I just removed the fi!ter, cleaned up any excess oil, left it to stand for a while, fitted a new filter and started the mower. There was lots of smoke as oil had gone into the carburretor etc but after a few minutes it burnt off and ran normally.

The OP's mower won't even crank :-(

subjecttocontract

Yes I'm aware of that. But if he has a paper air filter, he might want to check it's not soaked with engine oil. Nobody has so far mentioned air filters on this thread.