Mower coil resistance value

[Burnerman]

As the machine runs well enough once it manages to start then there isn’t too much wrong.
Its a cold start issue so there are a couple of things to consider.
1) the primer bulb isn’t delivering its puff of air into the carb, or more accurately the air space above the fuel in the float chamber.
Maybe the bulb has a split or maybe there is a one way valve in the primer stem leading into the carb.
The bulbs are generally removable, being held tightly in by a plastic ring clip.
2) Maybe the fuel level in the float bowl is too low and therefore it is difficult for the primer to push the fuel up through the emulsion tube. Unfortunately this isn’t adjustable as the float is plastic and therefore not bendable, unlike the brass systems of old.

See if the engine starts without it’s new fuel filter.....unfortunately not all engines like one, good idea though it is.
John

 

[ipbr21054]

Ive removed the whole thing at it screws into the carb,putting my finger over then end i feel resistance and cant blow.
Asoon as i move my finger i can feel the air no problem.
I think there isnt a split / leak as then i would expect to blow even a little when my finger is over the end but this isnt possible.
No sign of a one way valve as with the plastic clip out & red rubber bulb removed i can blow both ways.

If i start to unscrew the 10mm bolt where the float is held to the carb i then see pretty much straight fuel coming out over the top of the metal float bowl.

I still cant see why it will not start,i mean its the same as sent out from new in that i mean the primer bulb isnt smaller its the same size.
Fuel is flowing perfect & i can also see it in the fuel filter.
I did try before without filter but no difference.

Im expecting something to be broken / worn but there isnt so this keeps me scratching my head.

The red primer has a hole in one end but i assume that is there so after i have squeezed it then it feels up again with air as otherwise it would suck the fuel out of the float bowl & fill up the primer bulb itself.

Is there anything i can do with regards a manual test to narrow it down.

In photography there is an air primer which is larger than on the mower which also does the same job to remove dust on the camera lens.

Wondering if i tried that as its more air entering the float bowl ?

I know i wont be buying one of these thats for sure

 

[Burnerman]

A head scratcher indeed!
When you press the primer, as we’ve discussed, fuel needs to jump out of the emulsion tube and into the carb venturi.
If this doesn’t happen then a cold start will be difficult.
The air from the primer can go in two directions. First, it goes into the float chamber as we know. However, it is also possible for the air blast to go out of the back of the carb, out of one of those small brass drillings to the side of the main venturi, but the size of this orifice should send the air into the float chamber as intended. Don’t ask me why this isn’t happening!
Can you put a finger over the carb venturi - air filter off- and choke the engine that way as you try to start, or is this impossible?

The hole in the primer bulb is to allow air back in, but of course your finger prevents air escaping when you press it.
John

 

[Burnerman]

I should also have said, there needs to be a perfect air tight seal between the float chamber bowl and the carb itself......yours has slight damage but to be honest I would have expected a fuel leak from there if it was faulty.
John

 

[Burnerman]

Another suggestion....
Are you certain the black plastic block is the correct way round?
John

 

[ipbr21054]

Ok
The seal has been on / off a few times but looks tatty BUT no leaks at all.

No not certain about black block,i cant even remember if i tried it the other way as ive had it on / off so many times.
From memory one side is flush & the other has a driiled hole "BUT DOESNT GO RIGHT THROUGH" this hole then leads to a groove down the block.
Im sure its fitted with hole / groove engine side as opposed to carb / air filter housing side.

 

[Burnerman]

In your post #24 you mentioned that you could get some fuel to appear from somewhere, but I guess that's not happening now.
All fuel, be it normal running or cold start has to pass through that main jet.....it hasn't blocked up again?
Are you pressing the primer quickly, maybe 6 presses in quick succession?
John

 

[ipbr21054]

See attached photos.
From memory i could see a spray of fuel from the arrowed hole.
BUT
If i press the primer say 10 times it starts but chugs & youve got your fingers crossed its going to go.
Same as before a squirt of brake cleaner stright into air filter housing with foam element remote & first pull starts & sounds great,only to burn that off & chug or stall then im pulling & pulling

The hole / groove is shown in nylon block.

 

[Burnerman]

Right, that’s a bit more info!
I think you are going to have to juggle the number of primer pumps because I think you are flooding the engine, especially if it recovers maybe blowing a little black smoke.
Try say 4 quick presses then immediately going for a start - if it’s reluctant maybe one more then try again.
John

 

[ipbr21054]

OK
My job for tomorrow

 

[ipbr21054]

Afternoon,
3 press but no joy.
Tried 4,5,6 then started but does that mean it needs 9 presses Ha Ha

Running & cut the gras again but sounds like a kitten & want it more like a tiger.
If anybody was walking past they would think i had the vacumm & not a mower.
Not sure if im used to the loud engine of my R484SP but the height adjusters on this mower has like 5 different settings front / rear.
With the engine purring like a kitten its got no chance of cutting anything when the height adjusters need to be at the max height.

I assume the max height is for longer grass 7 not tiny little mice to crawl under it to change the oil ?

Joking aside these really need some kind of throttle.
I assume the bar & spring setup from engine shaft to carb butterfly is that ?

Either way im still not happy.
I wouldnt sell it as i wouldnt have any confidence of the customer being happy only then for it to arrive back here the next day or two.
All the others ive fixed for friend / family i put my hand on my heart & say i would stand by what ive done,This thing though ha ha ha ha ha ha

Did look / touch the carb block as you mentioned as i assumed its the correct way fitted or it would even start ?

 

[Burnerman]

At least we have a start up situation now....try it again in the morning to see if you can establish a reliable sequence.
At this time I'd leave everything alone to settle down, and that includes the black emulsion block.
Are you saying that the engine isn't revving fast enough? Obviously the speed is set by the internal governor but you may be able to improve things by slight bending of the governor rod. Don't overdo it, but you should be able to bend it back again if you do. Keep the tickover adjustment screw on the high side, too.
John

 

[ipbr21054]

Will check things out in the morning.
Yes engines seems to not be revving enough.
The governor rod connects with the linkage on the carb.
So one direction opens throttle butterfly & the other closes thus acting as a choke.
So which way should i be heading

 

[Burnerman]

Consider putting a slight kink in the rod from the governor, effectively shortening it a fraction. Best to leave the damping spring alone.
John

 

[ipbr21054]

I tried to start it with a few pushes of the primer & pulling then more & pulling......................

Got it going but up / down its all ok then its going to stall scenario.

I bent the rod a little leaving the spring but not much difference.
Bent it a little etc etc to the point this isnt working either so i put it back as it was before i bent it.

Total rubbish i think this is but i dont like to be won over