Range Rover 3.5 on Strombergs running rich

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vanquishspirit
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Range Rover 3.5 on Strombergs running rich

Post by vanquishspirit » Sun Sep 23, 2018 7:55 pm

I am slightly running out of ideas! I have a 1972 running rebuilt Stromberg carbs but it runs seriously rich. The plugs are very sooty, not oily, but sooty. I have set float levels, checked they are not flooding, I am assuming I would see fuel emerging from the top of the jet in the venturi if the electric fuel pump was overcoming the new float level valves.
I have gone back and forth on whether this is electrical, weak spark, or carburation. Clearly if I had a set of good carbs to compare that may be the best way to find out whether its the carbs or not. Given the fact that each carb feeds 4 separate cylinders, its odd that all spark plugs are sooty. The inside of the tailpipe is like the inside of a coal chimney! What can I be missing I wonder?



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ChrisJC
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Re: Range Rover 3.5 on Strombergs running rich

Post by ChrisJC » Sun Sep 23, 2018 8:21 pm

Problem with the choke mechanism?

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Re: Range Rover 3.5 on Strombergs running rich

Post by unstable load » Sun Sep 23, 2018 11:34 pm

Is it all plugs or the ones from one carb?
I would suggest reset all to basics and begin again. Start with the choke, like Chris suggests.
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Re: Range Rover 3.5 on Strombergs running rich

Post by garrycol » Mon Sep 24, 2018 3:19 am

The weight of oil you put in the dash pots can change the mixture - so ensure you have the correct weight oil in them and the correct amount.

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Re: Range Rover 3.5 on Strombergs running rich

Post by vanquishspirit » Mon Sep 24, 2018 7:31 am

thanks chaps. I shall try the dashpot oil. I am using 20/50 from memory. Yes its all plugs . Reference the choke, I think , not 100% sure, that this only operates on one carburettor and hence will not enrich 4 of the cylinders. Its the early type choke that works on a rotating disc system. As you apply full choke, it lines up larger holes allowing more fuel to be pulled from the fuel bowl directly into the venturi. I have not pulled it apart as its a mechanical item that looks like it cannot be mis fitted, but sometimes its the things you take as fine where the fault lies!

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Ian Anderson
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Re: Range Rover 3.5 on Strombergs running rich

Post by Ian Anderson » Mon Sep 24, 2018 4:45 pm

Fuel pressure?
Should be 2.5 psi

Too high and they run rich

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Re: Range Rover 3.5 on Strombergs running rich

Post by vanquishspirit » Thu Oct 11, 2018 4:18 pm

thanks Ian. The problem seemed to be that the float levels had been set too high. Allied to this one carburettor was sticking from time to time and not returning fully when throttle was closed. It seems pretty good now thank you. I checked on the fuel pressure and was told the fuel pump was a correct type for Range Rover and they had sold hundreds!! yes ok then

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