The_Yellow_Ardvark
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Seal that with non setting gasket material. when re-assemble.
- Thread starter jimbo84
- Start date
Seal that with non setting gasket material. when re-assemble.
The_Yellow_Ardvark
https://www.death-clock.org/
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A Norbert I know collects "stuff" like this.
I can normalcy beat them into a life.
I can normalcy beat them into a life.
Screwdriver
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Two stroke exhaust is the equivalent of a four stroke valve. Back pressure closes the dirty big hole in the cylinder and this allows the fuel charge to compress as it gets blown out from the crankcase as the piston descends.
A crude stroker might run without an exhaust but it will run like a dog.
New carb came yesterday. Fitted and the engine now runs...
however it is running slow and generates little to no power. It doesn’t get fast enough to bring the govener in and close the throttle. It did run very fast briefly sending the voltage off the scale before the govener closed the throttle but then back to slow speed.
Removed and refitted carb with fresh hylomer gasket, still the same. Only adjustment on the carb seems to be the throttle closed position screw but the engine doesn’t get fast enough so doesn’t move the throttle so can’t be that and then another screw which I'm guessing is the supply when the throttle closes, it makes no difference adjusting this screw.
Also makes no difference whether the exhaust is fitted or not so in my mind that rules out the exhaust.
however it is running slow and generates little to no power. It doesn’t get fast enough to bring the govener in and close the throttle. It did run very fast briefly sending the voltage off the scale before the govener closed the throttle but then back to slow speed.
Removed and refitted carb with fresh hylomer gasket, still the same. Only adjustment on the carb seems to be the throttle closed position screw but the engine doesn’t get fast enough so doesn’t move the throttle so can’t be that and then another screw which I'm guessing is the supply when the throttle closes, it makes no difference adjusting this screw.
Also makes no difference whether the exhaust is fitted or not so in my mind that rules out the exhaust.
angellonewolf
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with the exhaust removed can you see the piston does it look bad ?
Have a watch of https://www.youtube.com/user/mustie1 on youtube, you'll find everything you need to know about getting old small engine stuff running.
Jet sizes look identical.
Piston is good from what can be seen of it through spark plug hole and exhaust port.
Messed about with sparkplug gap which got it running upto speed.
Stopped running again now, quick check of spark and no spark whatsoever. Feel like I’m chasing a never ending cycle of various faults round this tiny machine. It was suposed to be a cheap alternate to save me fuel instead of running the big genny on days when I only need to run the fan or bench grinder in the workshop.
It’s gone beyond economical repair (it had a long while ago if you take into account time spent). It’ll be heading to the scrapyard as you can pick them up running for cheap.
Piston is good from what can be seen of it through spark plug hole and exhaust port.
Messed about with sparkplug gap which got it running upto speed.
Stopped running again now, quick check of spark and no spark whatsoever. Feel like I’m chasing a never ending cycle of various faults round this tiny machine. It was suposed to be a cheap alternate to save me fuel instead of running the big genny on days when I only need to run the fan or bench grinder in the workshop.
It’s gone beyond economical repair (it had a long while ago if you take into account time spent). It’ll be heading to the scrapyard as you can pick them up running for cheap.
Cheers, I’ve had a watch of his vids already as there was a link to him earlier in the thread, found them very helpful and picked up a few pointers for future.
before you bin it, some 5 minute checks to make sure..
- check the connection to the spark plug cap, they can be pretty poor, a lot are just screw on to the wire which is a pretty crap method, but it's cheap, but also prone to corrosion..
- you could also try another plug, don't need to buy one, any plug to at least prove the theory if theres spark, if the coils are gone or it's a dodgy connection.
- Could also be a low oil / pressure switch blocking the spark stopping it running... is there oil in it... sorry for the basic question, not meant to insult your intelligence in any way...
- stop start switch, try it on / off a few times in case it's a dodgy connection / contact
etc etc worth a quck look anyway.
- check the connection to the spark plug cap, they can be pretty poor, a lot are just screw on to the wire which is a pretty crap method, but it's cheap, but also prone to corrosion..
- you could also try another plug, don't need to buy one, any plug to at least prove the theory if theres spark, if the coils are gone or it's a dodgy connection.
- Could also be a low oil / pressure switch blocking the spark stopping it running... is there oil in it... sorry for the basic question, not meant to insult your intelligence in any way...
- stop start switch, try it on / off a few times in case it's a dodgy connection / contact
etc etc worth a quck look anyway.
Thanks for your pointers, I've taken the spark plug out of the big genny which happens to be the same plug and no joy with that plug that I know is a good one. I thought the same with the plug cap so unscrewed it cut the lead back 10mm and screwed back in. I've metered the two cables that connect to the coil and it's getting 18v AC from the flywheel when turning over (not sure what it should be) which also includes the switch in the circuit which suggests the switch is ok too although I could just short out the terminals behind to eliminate the switch from the circuit entirely.
I've got 5k ohms resistance in the plug cap which is what is stamped on the casing for it. Measuring across the coil terminals gives me 0.4 ohms and the plug cap to either terminal is open circuit but I've no idea what those measurements should be.
It's a two stroke so no oil or oil pressure switch circuit.
just tested a two stroke chainsaw coil, sorry it's not a generator, but the only 2 stroke I've got on the bench at the moment. Don't know how comparible the values are, but might give you some idea.
positive coil to plug lead, its showing 8.4 K Ohm.
coil terminals / windings 1.4 Ohm
positive coil to plug lead, its showing 8.4 K Ohm.
coil terminals / windings 1.4 Ohm
angellonewolf
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sure its got the right spark plug in ?
Thanks for doing that. It would appear then that the open circuit between coil positive and plug lead is the issue with mine.
Found on ebay that you can get coils on the slow boat for £3, might be worth a punt at that.
It came with the one in that it had run on for years and then I've had a replacement of that one and the one from my bigger genny is the same. Had it running on al three at various stages and conditions of running, now totally dead.
Screwdriver
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...but you said you had a good spark? 
I feel cheated.
I feel cheated.
...but you said you had a good spark?
I feel cheated.
It did, been running with the new carb today then the spark vanished.
It also has an intermittently faulty fuel valve that sometimes allows fuel from the tank and sometimes doesn't.
it has a gremlin fairy that likes to move around the machine turning various faults on and off to really get me wound up with it.
