Unable to start MS170 so advice needed for me to rule things out
- Thread starter ipbr21054
- Start date
Plug out & with saw upside down pulled a few times but was dry from me leaving plug out all night.
Screw all the way in as its left hand thread but not starting.
Same again different plug but no change.
Also did the same but with wire off coil just in case but still no change.
This was done with air filter off so now i see wet fuel out back of carb as you would expect pulling it many times & not firing.
Im expecting it to cough / splutter at least as if it wants to start but what i see / hear is the same as if the plug lead is off plug & your pulling the cord.
If the plug sparks & fuel is present in the way of the carb doing its job or me squirting some carb cleaner in the chamber surely the two should talk to each other & BANG but nothing
Screw all the way in as its left hand thread but not starting.
Same again different plug but no change.
Also did the same but with wire off coil just in case but still no change.
This was done with air filter off so now i see wet fuel out back of carb as you would expect pulling it many times & not firing.
Im expecting it to cough / splutter at least as if it wants to start but what i see / hear is the same as if the plug lead is off plug & your pulling the cord.
If the plug sparks & fuel is present in the way of the carb doing its job or me squirting some carb cleaner in the chamber surely the two should talk to each other & BANG but nothing
Are you sure the throttle is wide open when trying to start?
Has the machine ever run with this carburettor?
John
Has the machine ever run with this carburettor?
John
I've no real idea what is going on here, but maybe the engine is getting a good drench of fuel preventing ignition?
Try starting with no choke, then half choke, throttle wide open.
It's usual for petrol to be pushed back out of the carb, that's just part of the two stroke design.....are the fuel pipes in good order?
I've never known a flywheel key to shear on these (in fact it is cast into the flywheel itself) but you could always pop the flywheel off just to rule this out.
I'd be trying another new carb, personally....did this carb work on the previous engine?
John
Try starting with no choke, then half choke, throttle wide open.
It's usual for petrol to be pushed back out of the carb, that's just part of the two stroke design.....are the fuel pipes in good order?
I've never known a flywheel key to shear on these (in fact it is cast into the flywheel itself) but you could always pop the flywheel off just to rule this out.
I'd be trying another new carb, personally....did this carb work on the previous engine?
John
When I turn flywheel & I assume that where the coil talks with the magnet to generate the spark I do see the shaft turning with the but the same time as flywheel is being turned. When I took old one apart I did notice there is no way for it to fall out so as it all spins as opposed just one and not the other I can see it’s fine.
Only fuel pipe from memory is tank to carb.
I didn’t recall seeing or taking another off.
When I removed the only pipe to the carb fuel comes out freely no problem.
You mentioned before about carb.
The carb fitted is new and fitted same time as engine assembly Saturday.
In respect of butterfly that I can see in car. It closes 100% when choke is on.
You say fully on.
What I see is butterfly turn 90 degrees from closed at say North / South to open now horizontal ie East / West.
Only fuel pipe from memory is tank to carb.
I didn’t recall seeing or taking another off.
When I removed the only pipe to the carb fuel comes out freely no problem.
You mentioned before about carb.
The carb fitted is new and fitted same time as engine assembly Saturday.
In respect of butterfly that I can see in car. It closes 100% when choke is on.
You say fully on.
What I see is butterfly turn 90 degrees from closed at say North / South to open now horizontal ie East / West.
Just to add.
Choke off & me not touching throttle lever at all I use carb cleaner in plug hole.
Pull saw over and not even a splutter doing it that way.
I tried this way to file out lake of fuel etc
Choke off & me not touching throttle lever at all I use carb cleaner in plug hole.
Pull saw over and not even a splutter doing it that way.
I tried this way to file out lake of fuel etc
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just a point or two - not intended as criticism.
If a flywheel key has sheared, the flywheel will still turn on the crankshaft - just not at the correct time - but a spark will still be present.
The carb will have only one fuel pipe, but the tank will have a breather of some sort......often beehive shaped which needs to be clear.
Has this carburettor ever worked correctly at any time?
A cold machine will never start unless the throttle is fully open - sorry but I don't understand the second line of post #24.
John
If a flywheel key has sheared, the flywheel will still turn on the crankshaft - just not at the correct time - but a spark will still be present.
The carb will have only one fuel pipe, but the tank will have a breather of some sort......often beehive shaped which needs to be clear.
Has this carburettor ever worked correctly at any time?
A cold machine will never start unless the throttle is fully open - sorry but I don't understand the second line of post #24.
John
I will pop the flywheel off again to check.
Tank breather I think is like a small rubber grommet with a hole in the top.
Phone changed text.
I said I used some carb cleaner down plug hole to rule out any issue with carb. I expected it to splutter to show a sign it was going to start but just the same as any other attempt. Nothing to show any life. Like mentioned it was like pulling saw over with the plug lead off.
I will try a video to show you.
Carb is new and as saw hasn’t started the answer at present would be no.
Tank breather I think is like a small rubber grommet with a hole in the top.
Phone changed text.
I said I used some carb cleaner down plug hole to rule out any issue with carb. I expected it to splutter to show a sign it was going to start but just the same as any other attempt. Nothing to show any life. Like mentioned it was like pulling saw over with the plug lead off.
I will try a video to show you.
Carb is new and as saw hasn’t started the answer at present would be no.
If you remove the plug, put your thumb over the plug-hole, and crank it over, watching for a spark - does your thumb get blown off, at around the same instant as the spark? You thumb will be blown off, on the approach to TDC-ish, which is roughly when the spark should occur.
Haven’t done this but are you referring to whether the key is broken on crankshaft this timing out ?
Engine is new.
Obviously I’m using magneto from when it was stripped.
I’m also going to remove exhaust and also both wires off coil.
Unbelievable what an issue this has become.
I understand what you’re saying. TDC & spark then creates the bang & sends piston back down to do another cycle.
Engine is new.
Obviously I’m using magneto from when it was stripped.
I’m also going to remove exhaust and also both wires off coil.
Unbelievable what an issue this has become.
I understand what you’re saying. TDC & spark then creates the bang & sends piston back down to do another cycle.
Question regarding key on crankshaft.
I’ve just looked at old engine that I removed. The crank has a key way and nothing else.
On car & bike engine there wood be a woodruff key that you tap into the key way on the crank.
Is this the same situation for this saw or does the magneto have a protrusion that aligns it thus not needing a woodruff key ?
I’ve just looked at old engine that I removed. The crank has a key way and nothing else.
On car & bike engine there wood be a woodruff key that you tap into the key way on the crank.
Is this the same situation for this saw or does the magneto have a protrusion that aligns it thus not needing a woodruff key ?
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