Advice needed please with Hayter mower
 

Can someone advise on my Hayter Harrier, started it today & straight away it started puffing out loads of smoke & smelt horrible, the smoke soon burnt off & mowed as usuall. When i came to restart it the pull cord was very tight & couldnt get a full pull on it.As soon as i took the mucky spark plug out & pulled the cord again it pulled nicely as felt like it should.
I have unbolted the head & noticed the top of the piston has a large round patch of thick gunky dried oil on it, there are also two (what i think are valves) visible with the head removed, one of these is a clean metal,the other is gunked up with wet oil, can anyone shed some light on what might have gone wrong here as id like to repair it myself (if i know what to replace)? Thanks in advance.

You haven't said what motor it is, but presumably it will be a good old Briggs & Stratton.
Knowing Hayter as being one of the better garden lawn mower manufacturers if it is a B&S it will be to an industrial specification and not like some of the engines they also make for the throw away market.

My suggestion is to first of all, drain off the petrol tank and refill it with VERY fresh clean petrol.
Second, buy yourself a new spark plug.
Thirdly, take the air cleaner off and have a good look at it. Is it a sponge filter and does it look to be well and truly full of muck? If it is, take a small bowl, put a small amount of petrol in it and wash the air cleaner out, then do it again and then dry it.

Put the whole lot back together and your engine should now start and run sweetly.

Advice needed please with Hayter mower
 

sarse wrote:
Can someone advise on my Hayter Harrier, started it today & straight
away it started puffing out loads of smoke & smelt horrible, the smoke
soon burnt off & mowed as usuall. When i came to restart it the pull
cord was very tight & couldnt get a full pull on it.As soon as i took
the mucky spark plug out & pulled the cord again it pulled nicely as
felt like it should.
I have unbolted the head & noticed the top of the piston has a large
round patch of thick gunky dried oil on it, there are also two (what i
think are valves) visible with the head removed, one of these is a
clean metal,the other is gunked up with wet oil, can anyone shed some
light on what might have gone wrong here as id like to repair it
myself (if i know what to replace)? Thanks in advance.

Had you tipped the mower before the problem occurred?

Hi there,

As mentioned above, its a good possibility that you've tipped the mower on its side. A 4 stoke engine like this has a wet sump of oil with an Air Filter on one side of the engine and an Exhaust on the other. It sounds very much like you have tipped the machine on to its Exhaust side and allowed engine to pass through the open Exhaust Valve and in to the Exhaust.

This would cause oil deposits on the piston / valves. However most of that is just down to age / use and happens to most engines after a while. The wet stuff is what has been forced through when the machine has been tipped over. As the exhaust box heats up it will burn off the oil and should clear on its own. Did you notice any oil coming from the spark plug hole when it was removed?

Again, as mented above, clean the air filter (if its the "sponge" variety or replace if its a paper cartridge type), replace the spark plug with a new one and while you have the head off its worth cleaning the worst of the wet gunk away prior to re-assembling the engine.

Re-fill the tank with fresh, clean fuel and check your oil level as this will have dropped due to the oil working its way through the engine. And away you go again...... in theory!

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