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TR2/3/3A TR3 Intake Fitting

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Jedi Hopeful
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I've fiddled with my 1960 TR3 for the last few months trying to get it to run properly. After it warms up it only wants to run with the choke pulled halfway out or so. A buddy of mine still thinks I have a vacuum leak somewhere, most likely the bottom of the intake manifold. I've removed it twice and re installed. How do you know for certain it is fitting over the positioning pins and sealing as it should?

Thanks, Donnie
 
Hi Donnie,

There should be a definite feeling of the manifold seating over those pins. Make sure the holes in the manifold are clear, and that there is nothing further in hanging up. Also, if you are not using the stock exhaust manifold, make sure that isn't interfering, and if you've shaved the head, check that clearance as well.

You can also spray stuff around where you suspect the leak (carb cleaner, for example), and see if that affects the idle (indicating it is getting drawn in).

However, the manifold leaking there is usually a pretty big leak, and it seems unlikely that just the choke would be enough to compensate.
 
Can you see that the gasket is evenly compressed when you remove the manifold?

Another way to prove a vacuum leak is to spray almost anything (eg carb cleaner or WD40) around the area where you think it might be leaking. If the engine note suddenly changes, you've just found a leak.

What I have done for many years is to leave out the studs & nuts that connect the manifolds together. I first hang the exhaust on the head studs, and then slip the intake into place by hand. That makes it easier to feel when it is in place over the locating pins.

I assume you've already checked that the carb pistons move smoothly throughout the range, and land with a distinct click if you drop them (with the engine not running of course).

Another distant possibility might be if you got some .090" jets rather than the proper .100" jets.
 
Here is the way I see it. You pull the choke to start it, but even after the engine warms up you still need to have the choke on half way. Perhaps the timing is so retarded that you need the fuel the choke provides. How quickly does it start when cold? What is the compression? You might have low compression that worsens when the engine is warm.
 
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