Author Topic: Carburettor Adjustment.  (Read 4163 times)

Grasshopper

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Re: Carburettor Adjustment.
« Reply #15 on: 13 June, 2020, 05:53:18 pm »
Hello Polybus,
Looks like a nice little JAP motor, glad it is running good now for you.
Looks like you have a couple more Projects waiting to go in the pictures.
Cheers,
Grasshopper Max

Beech

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Re: Carburettor Adjustment.
« Reply #16 on: 13 June, 2020, 09:47:06 pm »
Hello Polybus,

 your JAP looks good, and nice to hear it is running well now, I have a 2A and a 2S one is mounted on a fire fighting pump and I think it's original colour was green, the other is very much the colour you have painted yours do you mind advising what colour that is?

Regards Beech.

cobbadog

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Re: Carburettor Adjustment.
« Reply #17 on: 13 June, 2020, 09:59:45 pm »
Very nice job and well done. with the air mixture settings I did say that almost all settings start at 1 1/2 turns out, well here is one of the exceptions.
A trick I use for setting timimg on the little mower engines is to remove the spark plug and drop the screw driver down the plug hole to touch the top of the piston. Once the screw driver is at TDC I mark the shank with a texta, pull the driver out and mark the shank all the way around. The width of the texta mark is getting close to 3/16" so put it back and wind the engine backwards until the top of the mark is level with the plug hole. Then move the stator plate to where the points are just breaking.
Cheers, John & Dee. Coopernook. NSW.

Polybus

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Re: Carburettor Adjustment.
« Reply #18 on: 13 June, 2020, 10:12:03 pm »
G'day Beech,

Hello Polybus,

,.... the other is very much the colour you have painted yours do you mind advising what colour that is?

Regards Beech.

My J.A.P. was this colour originally - I found a fair bit of it when I stripped it down. Here is the colour I used - it is very close to the original.


Hope it helps with your restoration  :)

Polybus

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Re: Carburettor Adjustment.
« Reply #19 on: 13 June, 2020, 10:15:05 pm »
Hiya CobbaDog,

... A trick I use for setting timimg on the little mower engines is to remove the spark plug and drop the screw driver down the plug hole to touch the top of the piston. Once the screw driver is at TDC I mark the shank with a texta, pull the driver out and mark the shank all the way around. The width of the texta mark is getting close to 3/16" so put it back and wind the engine backwards until the top of the mark is level with the plug hole. Then move the stator plate to where the points are just breaking.

I reckon I might give that a try next time - its such a hassle taking the head on and off all the time just to make a tiny adjustment to the timing. Thanks for the tip.

Polybus

Polybus

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Re: Carburettor Adjustment.
« Reply #20 on: 13 July, 2020, 11:54:38 am »
Well - its done  :)

Reasonably happy with results - but I will probably still try to get it running better, although maybe I am starting to chase my own tail.

I am not overly familiar with these old engines, so what do you guys think?

Is it running well?

Should I keep trying?

Or is it as good as it's going to get for a 65 year old little air cooled engine?

I think it might still be running a bit rich (you can see a few puffs of smoke when I accelerate, but normal running is smoke free), so I'm sure that can be improved.

In the video, it is really cold when I first start it, so it starts with a little choke, warms up, and then I turn the choke off after 30-40 or so. Then various little carby tweaks and the video progresses.

If you look at the earlier "Running Again - Sort Of" video, around the 50 second mark I think it was running really well there, but too fast, maybe I should have stopped there and be happy with that.

Hope you enjoy seeing it run.

https://youtu.be/ED4pf3Cu2HA

Polybus


cobbadog

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Re: Carburettor Adjustment.
« Reply #21 on: 13 July, 2020, 04:37:07 pm »
Nice job, you should be pleased with the result. Try a shorter rope, it will be easier than that long one you have. The puffs of smoke I saw were blue in colour and that is the oil in the mixture maybe because it is not hot enough yet to burn it or a hotter plug is needed. The other thing to consider is that it has not run for a long time and needs time running to get everything running free or bedding in so that it will run at it's best.
Once on a transporter try and find something for it to drive. running it at low revs and no load tends to make them jump about a bit but under load they should run smooth. It was a good idea to fit the inline fuel filter too. It appears that your timing is spot on and fuel settings are so close to being right so just run it and at times bring the revs up higher for a while and then back down again. 2 strokes at or near idle foul plugs over a long time.
Cheers, John & Dee. Coopernook. NSW.

Beech

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Re: Carburettor Adjustment.
« Reply #22 on: 13 July, 2020, 10:05:42 pm »
Cobba,JAP 2a and 2S are four strokes, I have one of each, good little motors, but am just doing the 2A up and got new piston and bigends from England had a 20 thou over rebore and shells are 10 thou over, only to find the big end on the rod is oval and not round so am waiting for a reply from England if they have a replacement rod.

Beech

cobbadog

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Re: Carburettor Adjustment.
« Reply #23 on: 14 July, 2020, 04:01:23 pm »
Ok, thanks for that. That being the case it may simply need a good long run to free up the rings.
Cheers, John & Dee. Coopernook. NSW.

Polybus

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Re: Carburettor Adjustment.
« Reply #24 on: 15 July, 2020, 10:54:23 am »
I just checked the date on this little engine.

Manufactured in 1949  -  so as of the date of it firing up again - that's 71 years old!

I doubt much we manufacture today will still be running in 71 years time.

Polybus