JCB 3D Cold Start Aid

[magreg88]

Hi! I currently remake the entire electrical system on my JCB and I found a Glow plug in the air intake with fuel feed pipe. There is also an handle, under the Fuel cutoff handle, with the COLD START Mention on it. it seem to be connected to the CAV rotary fuel pump , and seem to actionned a spring attached to a little ''rotary pin'' under the pump.

I wold like to know if there is any timer for the glow plug, and I wold like to know what exacly the Cold Start handle actionned!

thanks!!

again, sorry for my english! i'm trying my best,but it's my second langage!

[essexpete]

There would not be timer for the heater, it should have a reserve of fuel available which is heated and released into the air intake. If it is working, and replacements a just a few £, then you should be able to turn the key to a preheat position (about 5-10secs) prior to turning over the engine. Sometimes in cold weather a short delay before a second attempt of heat/start will give a good result. For the sake of a few £ it might be worth changing the heater anyway as they are prone to leaking diesel into the intake when running when past their best.

[martyn williams]

Those "thermostart " devices can be tempremental. Sometimes they just leak fuel into the intake as essexpete says.I had a problem early days on my compressor when the fuel would would dribble too much and would result in a large pop when heated resullting in me running away from it. They can be modified by just fitting a heater into the air manifold and do away with the fuel feed.
Martyn

[magreg88]

I will check if mine is leaking, I connected it directly on the Batt and the element is working,

I would like to know what the cold start handle actuate when you pull it

thanks!

[kaos]

I'm not familiar with this model, but from your description it does just what it says, activates the injection pump's cold start feature, also known as "excess fuel device". This simply pulls out the stops that regulate how much fuel is injected at a maximum at each stroke. We once had this get stuck on in a tractor. All that happened was that if you overloaded the engine, it would start spewing great billows of black smoke, as the governor tried to compensate for the drop in RPM by increasing the amount of fuel past what the engine could burn.

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Best regards, Kári.

[FOWLER MAN]

Hello,
I'm not familliar with this particular aplication either.
I have worked with CAV rotary pumps since they were first introduced in the late 1950s and I am not aware of any being fitted with a manual excess fuel device.
Some ,however, were fitted with a cold start device located as described under the pump. This retarded the injection timing for easier starting. The earlier ones as used on some DB tractors were opperated by a "T screw" at the same location which was screwed out to start then back in after starting.
Fred

[kaos]

Ah, I was not aware of this type of cold start. If this is a rotary type pump, then that's probably it; I've only ever seen the "excess fuel device" used with the more old fashioned "in line" pumps: older Zetors (the tractor I mentioned in my previous post), Fordson Major engines as fitted to our old JCB 3, and an early 70's Ford 3000.

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Best regards, Kári.

[essexpete]

I am sure that one 3C we owned had this cold start device on a cav rotary but the cable was broken and it never worked. Always used the heater if it was a little cold.

[magreg88]

Thanks you all for the info! I have a Cav rotary!, I finally finished the electricity, after about 50h of work, I start over the entire system from 0 , but now everything is working!