irregular tick-over

Micky

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Hi guys.
Been trying to sort out my diesel engine idle speeds, which flutter from 1000 RPM up to near 2000 RPM. up down, up down.
Thought the problem was air getting into the system. Decided to bleed the fuel lines...no joy. Bled it again, and again still no different.
So striped down all pipes and joints from new fuel tanks to engine, refitted all new pipes/olives etc, used the proper sealing paste, made sure that NOTHING was left out, bled the engine and hey presto...it still revs erratically, what a pain in the bum..Has anyone got any ideas as to what else to look for.
 

Its_Only_Money

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MIcky, assuming that the idle speed used to be somewhere under 1000rpm and hasn't been mechanically adjusted then your problem sound's like excess fuel rather than air in the fuel line (if you have would up the idle setting to stop it stalling then let me know now....).

So for excess fuelling it sound's like an injector sticking open or not closing properly (you didn't say what engine, assume it isn't the Mercury 8hp in your profile /forums/images/graemlins/confused.gif ), or maybe a problem in the injection pump, least likely IMHO might be it has a leak of engine oil into the cylinders and it is partially running on that????

Have the injector(s) been serviced/checked at all, how old is the motor?
 

capnjack

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Am I right in saying your engine has indirect injection with a swirl chamber?

I tend to agree that there is air getting sucked in somewhere. Irregular idling is commonly caused by a leaking manifold gasket.

Do you get any smoke apart from the norm. if so, what colour?

The only other areas left to check would be the fuel pump, cold start and fast idle.
 

Micky

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CapntJack, when you say "fuel pump" are you referring to the lift pump or the injector pump.

There is no noticable smoke
 

Jcorstorphine

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I had this problem with my BMC 1500, turned out to be the injection pump governer, you may need to take the pump off and have it serviced by your local CAV engineers. Take note of the engine position and mark the injection pump position so that you can re-time it
 

david_bagshaw

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does the injection pump have a vacume controlled governor?, as an air leak here would produce your symptoms ,with black smoke though.
 

Micky

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There's no black smoke, it is pure white like steam from a boiling kettle.
That reminds me, it's time for a cuppa.
 
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