Anyone know anything about small 4 stroke petrol engines?

Mine starts (only when choke is where it's meant to be for starting), runs for about 1 or 2 seconds and konks it... haven't used it in 18 months... before that, never had a problem...

Things done:

- Charged battery.
- Drained old fuel.
- Re-fueled with new fuel.
- Checked spark plug... removed... it starts - could it still be the plug? Bunnies didn't have this model.
- Pulled the carburettor off... cleaned... fuel runs into carbi fine... I think...
- Oil appears clean and at right level.

Thoughts, ideas or comedy??

What is the brand and model of engine?

Does it have a primer bulb? Does it have a choke? (Is the choke just a setting on the throttle?)

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Pugwash said..
Anyone know anything about small 4 stroke petrol engines?

Mine starts (only when choke is where it's meant to be for starting), runs for about 1 or 2 seconds and konks it... haven't used it in 18 months... before that, never had a problem...

Things done:

- Charged battery.
- Drained old fuel.
- Re-fueled with new fuel.
- Checked spark plug... removed... it starts - could it still be the plug? Bunnies didn't have this model.
- Pulled the carburettor off... cleaned... fuel runs into carbi fine... I think...
- Oil appears clean and at right level.

Thoughts, ideas or comedy??

make sure the oil is actually oil and not thinned with fuel,also your carby will have to be cleaned out and all jets and emulsion tubes clean, modern fuel will react with brass and alloy and leave white corosion every where and cause blockages this is best done professionally if you dont know carbs

It's a super-duper Chonda

www.bbta.com.au/bbt-15-20hp-electric-start-mulcher-chipper/

No primer bulb, separate choke... oil looks ok, but I know **** [not very much] about engines.

Some evidence of corrosion in carby (bowl?), but only very minor.

Until today has started as soon as the key is turned... still does... just dies straight away. Also have the BBTA 4 stroke 5 tool thing... whipper snipper... pole saw... other stuff... that thing gets more regular use and starts first pull 70% of time...and nearly always on the second pull if it didn't start on the first...

The thing was a complete weapon for making mulch! I bought it a few years back as the price quoted for removal of garden waste was only slightly less than purchase price... I had quite a few cubes of garden waste stockpiled... made about 3m^3 of mulch in 3 hr... oh and if folks think leaf blowers make some noise, they should hear this thing at full chat! It really will chip 120 mm by 80 mm branches... easily if only the bloody thing would start

Re check oil level if it is ok unplug the low oil cut out switch, if it runs replace switch.

^^^ did try that... but will test again in a more sciencey way... wasn't sure whether the switch would make a circuit open or closed! It's just at the end of one wire!

Yep I know the BBT company well. I bought their self-propelled mower 21' with B&S motor 750. $550Works fine for a week until it strikes something in the grass - then motor casing broke in half. Pricy exercise for a week job.No warranty as BBT said as you run over something in the grass. On my polite excuse that mowing blade is permanently fixed on the shaft and not a clutch or swinging blade to prevent the motor from stopping suddenly, disregarded.
Now I could see that BBT provide now plate with 4 swinging blades.
So I did order new B&S motor with mowing plate and hope that now for additional $400 mower have a second life for a longer than the week.Re your carburetor - it remains me another device with a similar motor, that stopped working. When I went to a mechanic - looked at the motor and decided that carburetor is completely rusted and needed to order a new one. Just bought on eBay new carburetor and waiting for delivery.

Ethanol fuel ???? By acsedent????
I have a mower, wipersniper and a high pressure cleaner that have all dune the same thing at the moment same tank of fuel it eats the rubbers out of the fuel system and cloges the jets in the carburettor. And everything else. It also forms yellow chunks in the bottom of the carby bowl.

I have a 6 hp suziki outboard and a Honda 2kva genotrator both 4 stroke. Both brought second hand and both where not run for a long period of time. Both I utubed cleaning carbi with no results. Both I took carbi to service centre to get electro cleaned $80 each. Both work perfectly now past 2 years with monthly run up.

However you may have a fuel blockage that is also possible.

Woaaah calm down calm down.
1)find inline filter between tank and motor remove and replace (70% this is it if it hasn't started for ages)
2) if this doesn't work check all fuel connections and hoses I spray mine with soapy water and you can see if it gets sucked in, fix these
3) this should of been 1 but make sure the arrow on your primer fuel line points the right way yes it happens a lot)
4) remove spark plugs clean and re insert ( change them if this keeps it running) change them if it doesn't as well.

5) your impeller probably is due for a change too, change it before you go for a huge run these can self destruct if brittle after an hour or two of running, this is poo I learnt once and once only.
6) if your fuelling has gunk inside like a smoker arteries this all goes into new fuel filter I always buy two filters change run than clean lines than run than ditch filter and replace with second new

6)commend razzonater for a job well done,

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Razzonater said..
Woaaah calm down calm down.
1)find inline filter between tank and motor remove and replace (70% this is it if it hasn't started for ages)
2) if this doesn't work check all fuel connections and hoses I spray mine with soapy water and you can see if it gets sucked in, fix these
3) this should of been 1 but make sure the arrow on your primer fuel line points the right way yes it happens a lot)
4) remove spark plugs clean and re insert ( change them if this keeps it running) change them if it doesn't as well.

5) your impeller probably is due for a change too, change it before you go for a huge run these can self destruct if brittle after an hour or two of running, this is poo I learnt once and once only.
6) if your fuelling has gunk inside like a smoker arteries this all goes into new fuel filter I always buy two filters change run than clean lines than run than ditch filter and replace with second new

6)commend razzonater for a job well done,

Good call 90%of carb problems start on a bench

Pull the carby apart. The old fuel would have evaporated and left some residue. Need to clean all the airways and then replace. Start and all ok. The lazy way is to partially open the carb and spary the crap out of it with carby cleaner (eaisly available from super cheap ( shead full of ****)) if spark is good then evaporated fuel will be the prob.

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Razzonater said..
Woaaah calm down calm down.
1)find inline filter between tank and motor remove and replace (70% this is it if it hasn't started for ages)
2) if this doesn't work check all fuel connections and hoses I spray mine with soapy water and you can see if it gets sucked in, fix these
3) this should of been 1 but make sure the arrow on your primer fuel line points the right way yes it happens a lot)
4) remove spark plugs clean and re insert ( change them if this keeps it running) change them if it doesn't as well.

5) your impeller probably is due for a change too, change it before you go for a huge run these can self destruct if brittle after an hour or two of running, this is poo I learnt once and once only.
6) if your fuelling has gunk inside like a smoker arteries this all goes into new fuel filter I always buy two filters change run than clean lines than run than ditch filter and replace with second new

6)commend razzonater for a job well done,

There's a filter on the fuel line in the tank... can't see another one between carby and tank... fuel seems to run OK into carby... will take another look tomorrow...

I don't understand 3... there's a primer fuel line? Line from tank to carby? Has always worked in the past and no mechanical changes...

Had to google impeller... not sure I saw that anywhere... what does it do?

BTW - job well done

On another note, anyone know why fuel was once a pinky colour and is now beer-piss pale yellow?

I think it will be the float in the carby bowl.... it will be gummed up and stuck from the old fuel.
So it is not allowing fuel to flow into the carb bowl as it is registering as full already.
as was previously mentioned a cheap easy fix is to spray a heap of carb cleaner if that doesn't work open up the carb and spray directly

Sorry no impellor (tgought you were talking boata for a sec ) i read fast and poorly.
Anyway now you know about impellors.
Fuel does fo off after a while also on my whipper snipper it has cheap plastic clear hose which after time fets eaten by the fuel and actually leaches in there ( probably may off happened on wood chipper)
New fuel and a flush for sure is due.
Check ya spark plugs and if possible remove the fuel hose on the bottom of the tank and flush both ways ( dispose of fuel appropriately)

Try some nitrous.just a thought!

I have a lawn mower that also sees little use. It does the same thing; starts right up, revs, then dies. I finally figured out that it was the governor.

Jiggled, lubed, and cleaned up the linkage and it works again.

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desertyank said..
I have a lawn mower that also sees little use. It does the same thing; starts right up, revs, then dies. I finally figured out that it was the governor.

..bloody politicians getting in the way of hard workers. again.

I guess it might be time to visit your local mower shop and ask them.

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FormulaNova said..
I guess it might be time to visit your local mower shop and ask them.

Yeah... that's the next step... I reckon it's the spark plug or the governor...

I have learnt a lot about small engines in this process. I have chainsaw which can be a bit of a pig to start... like yesterday... ripped the spark plug out, gave it a quick clean, started first pull...

I am probably stabbing in the dark...but here is my 2 cents.

I wonder if the exhaust is blocked? My whipper sniper started OK, but then wouldn't rev up. Took it apart, checked everything until I found a tip from the Internet. The exhaust was blocked with a few years of carbon deposit. So the machine was suffering from constipation ! Imagine that ?

May be your mower has some spider web or rubbish, or carbon built-up in the exhaust ?

If it actually starts and runs for a little bit, I doubt it would be the plug. If it were dirty enough to stop an engine, it wouldn't start.

I don't know about that particular engine, but Briggs and Stratons have a weird mix of springs and levers, but they still start and run, but they surge when the springs are not right.

I have a mower that has a Chinese knockoff of a Honda engine. The choke is activated through the throttle linkage and from the factory it wouldn't start reliably. It turns out the levers and wires were never adjusted so the choke was never really activated. Bending one of the metal tabs fixed it up and it starts first time and runs fine. I just hope they copied the Honda engine enough to make it reliable.

In your case, it still sounds like a fueling problem, but its hard to tell remotely.

I have a Honda Snipper.
Didn't use for a while.
Took it in for service. $45 later. running like a dream.

If you don't KNOW anything about it.
Don't waste your time.
Take it in to a bloke who does them for a living.
Worth every cent.
Believe me.

Unless you paid $85 for it and service is $60\70,

Just go out and buy another.
AND don't let it rest.
OR buy a proper one.

I've been through most gardening (and other tools ) in 75 yrs as a mechanic
and home owner.

Skill Chain Saw.
Everything else. HONDA.

Including wife's car.
But I'd never have a Honda outboard or Motorbike .

Merc Opti.... SUZI. and Maico....

Start it then let it die like it normally would.

On the next pull, hold the throttle wide open. She'll run like a pig until it clears it's throat and then will run like a dream.

Anything with a spark arrestor.....remove it.

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Porkyhorse said..
Anything with a spark arrestor.....remove it.

That was what happened to my whipper snipper. I did clean out the heavy carbon deposit with petrol, and it ran well again. I believe it is not a good idea to remove the spark arrestor, as it is there for a purpose.

Good advice chaps...

gunna check the exhaust. Can see exhaust gases plus a little smoke as it kicks over.

Anyone know how an oil switch(?) works? It's on 1 wire only... thought that could be killing it...

Tried opening the throttle on start several times...

Will entually take it to a pro... it's about 105 kg... so not that simple... can take the engine off the machine... can also buy a new engine for $350

pugwash, disconnect the oil sensor wire and see if it runs symptoms sounds like that is cutting out .make sure the oil level is correct better still change the oil.

Get your barby gas bottle and hose , crack open the valve so that it is letting a small amount of LPG into the carby air intake .
start the engine as per normal and see if it will run on the gas.
If it runs without stopping then you can safely conclude that the main jet in the carby is blocked.
The jet is located on the bottom where the fuel bowl is screwed on (10mm bolt) .
Get a sewing needle and insert inside the Jet and it should clear the blockage.
Use a air compressor also, if you have one, to blow through the jet .

The jet was blocked!!

Cleared with needle - lots of pale corrosion... reassembled the carby, turned the key and bang... my block gets to enjoy a 420 cc Chonda at full chat

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Pugwash said..
The jet was blocked!!

Cleared with needle - lots of pale corrosion... reassembled the carby, turned the key and bang... my block gets to enjoy a 420 cc Chonda at full chat

Great news ! When you are done, come to my place. 2.5 acres of virgin country. Sorry, no virgin though.