Hayter 48 keeps cutting out

I’m just doing my grass. It’s quite long so I’ve adjusted the height to its maximum and began to mow the lawn. It’s got enough petrol and give oil is full and clean. But it’s just decided to cut out. It starts and then the revs slowly decrease and then it cuts out. I seem to be having quite a few issues with this mower. Any advice?

 

How do you fix that?

 

Strip the carb and blow the jets out. Don't poke them with wire.

 

I’ve never done that before. It’s my first Petrol lawn mower.

 

If you don't feel confident doing it yourself, a tool shop will do it for about 30 quid or so.

How old is your mower and how much has it been used? If it's getting on a bit there's a good chance the spark plug is past its best. But if I was to bet without seeing it, I'd place most of my money on the probability that it's air intake is clogged with tiny bits of decomposing grass. Low revs tells me it's likely struggling for air (interesting factoid, on a carburettor engine, the throttle doesn't directly control fuel, it controls airflow, which has the side effect of controlling fuel, so a partially blocked air intake will have the exact same effect as the throttle being closed).

First thing I'd look at therefore would be the cleanliness of the air intake, and the air filter inside it. That should be easy depending on how accessible it is.

If the airway is clear and clean, if the mower is more than a year old, I'd whip the spark plug out and check for obvious wear or contamination. Unless it looked mint, I'd probably put a new one in anyway, because it is really a service part.

If it's old enough, I'd look at the condition and alignment of the points. Most modern engines don't have points anymore because the ignition is controlled electronically now, but I think small engines in mowers and the likes were late to the game on that point so may still use them.

The pattern forming here is if it were me, my order of investigation would be, airflow, ignition, fuelling.

 

Ended up taking it to a Lawn Mower repair shop they also buy and sell brand new mowers etc.

They have said they’ve stripped it down.

• 3 Cables
• Grass Deflector
• 2 Belts
• Possibly a Crank Shaft.
  
• Service

So it’s going to cost quite a bit to fix. So I’m not sure whether to sell it and try and make some money back for what I bought it for or pay the rather big bill.

 

They will probably offer you a silly price. Don't be taken in.

 

The trouble is it’s either pay it or go somewhere else. Or see do they want to buy it.

 

Seems odd if the crankshaft is knackered that the rest of the engine isn't. If it was me I'd be considering the cost of repairs, the likely value of the repaired unit, it's sale value now, and the cost of a brand new replacement. Oh and how long the repaired unit might last.

It's like with a car. Sooner or later they reach a point where it's more cost effective than it is to keep repairing.

 

You said in your first post the problem was cutting out. How old is the mower? The list you've been given above would suggest that replacement of any of those items is nothing to do with your original problem. I think they are trying to take advantage. I'd settle the labour bill and take it elsewhere for another opinion.

 

If it's 4 stroke, the belt might be the cam belt, which if worn will mess with the valve timing. The belt is driven by the crank, so if the crank shaft is excessively worn then again it's going to mess with the valve timing.

But there's the bit that is a red flag for me. Crank shafts don't really wear out under normal circumstances. It's very beefy and sits in a bath of oil, so as long as it's never been run for any length of time without oil in it, it should last forever, certainly longer than other more wearing components. This is why I think one of two things must be true. Either, the engine is done for, and any repairs now will just be a sticking plaster, or, the shop is trying it on.

 

With years of motoring and hands-on experience of engines, I would say that list is tripe. I have only had one crankshaft failure in 50 years motoring and that was due to someone else putting the wrong oil in the sump. Belt-driven camshafts are normally only OHC engines. My limited experience of mowers have all been side valve. The belt for the drive may well be worn and the throttle cable may be frayed but intermittently cutting out is almost certainly fuel starvation. We are talking basic technology here. It is not a Hayabusa.