JAP2A Strating

I have a JAP 2A which I have built up from bits of three others. I have a healthy spark and from time to time it will fire. There appears to be good compression. On one occasion it ran on Easy Start for about 20 secs but other than that it is dead. Can anybody advise what I am doing wrong, which I suspect is throttle/carb settings, or is able to set it up for me. I am quite prepared to pay the going rate to somebody who can get it running reliably.

I am based near Settle in North Yorkshire and could deliver in a range of say 100 miles.

Hi,

There are plenty of causes to investigate - blocked fuel line, unvented tank, wrong mixture setting, wrong idling setting, blocked jet,  stuck carburettor float and so on.
You should get some guidance from the manual. I don't have a copy but I sure someone here will have, or visit The Museum of Internal Fire website.

This forum is about problem solving rather than buying in services. Give us some more detailed info, pictures, video and I'm sure we'll be able to help.

If it ran for 20 seconds on easy start then its probably carb related, strip it down completely and give it a damn good clean, not to terse I hope

Maryalice

maryalice wrote:If it ran for 20 seconds on easy start then its probably carb related, strip it down completely and give it a damn good clean, not to terse I hope

Maryalice

No!

Those little JAP or Zenith carbs on the 2a/2s models are sensitive to getting the correct mixture for starting, I can only suggest playing with the mixture screw by trial and error until you get a result.

Pete.

Apologies for asking, but did you have choke fully closed and carb flooded? If so, then, as maryalice, infers something may be bunged up in the carb.  Bright light and magnifying glass required.

One other thought - I've had issues with Villiers engines refusing to start which turned out to be timing related.
I believe the correct setting for the 2A is 3/16" before TDC. Perhaps someone can confirm.

Many thanks to you all for your advice. There is nothing in the handbook about setting up the carb, it says it is set by the manufacturer and not to fiddle!! Less than heplful. Like most of the rest of the engine the carb was a mess so have stripped and cleaned. It is slightly different to the design in the handbook in that the handbook shows a slow running adjuster on the butterfly, there is none and also the handbook says the slow running mixture has no adjustment but it does have. Woodsman you are correct it has been flooding. I did get it to fire yesterday after drying out the plug and fitting whilst still hot I think my next step must be to try with the main jet aduster fully weak and gradually richen it to see what happens. Trouble is at age 83 keeping pulling the sting is getting a bit tiring!! I have checked the timing which I think is in accord with the handbook at 3/16 before TDC. My four classic cars never seem to give me this sort of trouble! However as it was a present I have to persevere

Sorry if I was unclear. I meant did you hold down the 'tickler' to flood the carb, thereby ensuring an initial supply of fuel. Any marks on the carb to help identify? Some pictures would be useful.

Re timing,  I slipped up in the early days by setting timing with piston 3/16" below top of cylinder rather than top of stroke. Contact breaker gapped correctly?

As for pulling the rope - try mounting a rubber sanding disk (no sandpaper) in an electric drill and holding against the rope pulley.

Something like this... Click Here

Just re-reading, I see you say the plug was wet which would indicate that fuel is getting through. It's looking more like an ignition problem. You say you have a healthy spark. Is that in free air? Maybe its not so good under compression.
The Clinton Field Service guide suggests testing in free air with a plug gapped at 150 thou!

Thanks to you all again for your interest and suggestions. It did run for about 20 seconds this morning but then died. The problem is I think carburation. If I remove the plug, dry it out and replace it will then fire, once. On removing the plug it is soaked, so too much fuel and this even with both jets fully screwed in ie closed off. I have checked the needle valve which seems to work OK. My only concern at present is the float which is OK but in the past has had a leak soldered up. Is the float too heavy and thus the fuel level in the chamber is far too high I wonder? Given up for today and tomorrow I work at a steam railway so it will have to wait until the weekend.

Which railway.

Maryalice

Good Morning May Alice, A Happy New Year.

It is the Embassy and Bolton Abbey Railway. I have worked there for the last four years. I help in the restoration of carriages. My work primarily is doors, door frames, window frames, floors, ceilings and other interior panel work. I go every Friday and am one of a small team of three who work together on these vehicles.

As Foden says the carb is sensitive to settings for starting. I have an old washing machine motor which I couple to the engine and then adjust the settings until it fires and runs. Its also handy for checking if pumps Etc work without having to fire up an engine

Rookesy wrote:As Foden says the carb is sensitive to settings for starting. I have an old washing machine motor which I couple to the engine and then adjust the settings until it fires and runs. Its also handy for checking if pumps Etc work without having to fire up an engine

That sounds like a good idea.

I wonder if the Air or Fuel needles are worn and not seating properly - close examination required. 
Spares including float available from L&S, assuming you have Zenith 13TC carb.

Rookesy wrote:As Foden says the carb is sensitive to settings for starting. I have an old washing machine motor which I couple to the engine and then adjust the settings until it fires and runs. Its also handy for checking if pumps Etc work without having to fire up an engine

I have an old Kohler "donkey engine" I use for that sort of thing, just roll it out, electric start and away she goes

Paul, Thanks once again. The card is a Zenith 12T not 13 was that a misprint and who are L&S? Being new to all this the name rings no bells. People I know for car carbs is Burlen of Salisbury from whom I have had very good service in the past. I think they do Zenith as well as SU for which I have used them.
Regards
Richard

see this thread:  https://ukengineforum.forumotion.com/t8756-j-a-p-2a-zenith-carb

I guess blue cat may be able to confirm. Don't know about 12T.

I'd certainly give Burlen a call.

L&S  Engineers  https://www.lsengineers.co.uk/catalog/category/view/id/68  Very helpful people.


Just came across this; https://forums.tomm.com.au/index.php?topic=5619.0

I've not heard of a Zenith 12T carburettor, the normal fitment for a JAP 2A is the Zenith 13T (or sometimes 13TC).

Do not confuse it with the Type 13TCA-2 which has the butterfly spindle rotated 90 degrees (and is found on Suffolk mowers).

Many thanks Blue Cat. I tihnk I have got it right. I have, would you believe, an original JAP Handbook for the 2A which states the card is a T12 and also a book on the These engines written by Fenner, orignally published in 1952, and this also states it is 12T. Interesting to note the reversal of the number and letter. Certainly the carb I have does not conform to picutres which I have found of the 13. There are similarities but they are not the same.
Thanks for you help and interest anyway.

Best wsihes,

Richard

No problem, do you have a picture of your 12T carburettor please ?

Thanks Blue Cat, have taken a couple of pics but found it beyond my limited IT capability to get them into a reply to you. I tried simply cutting and pasting without success then went into 'insert image' also without success. Any advice as to how to do it please?

Richard

Woodman has a instruction on how to do it on here somewhere

Maryalice

How to add images:


https://ukengineforum.forumotion.com/t9665-how-to-upload-images

Hope this works

That looks like JAP's own carburettor as their name is cast on the float bowl, they were discontinued in the late 1940's as they cut the engine out when on rotovators etc working at an angle and the Zenith carb was adopted then. However the JAP ones I had were not flange mounted like the Zenith (and the one in your pic) but had a spigot cast into the elbow which screwed directly into the cylinder.

Pete.