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TR2/3/3A TR3 carb float bowl

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emmett1010

Jedi Hopeful
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Hi Guys; two quick questions.
My front Carb float bowl on my H6 carbs starting leaking where the float assembly is attached to the bottom of the Carb. I tryed to snug it up some, and tore the rubber gaskets beyond use. I installed some copper compression washers, and it doesn't leak anymore, but I wondered if this can cause later/different problems?

The second question is the wiper motor wiring. My car is converted to negative ground. After complete disassembly it would appear that the motor terminals 1 and 2 are designed for a positive and a ground. Number one has a ground interuption for the park switch. Since it will not start without a ground, I assume that a switched ground, on the dash, would solve this problem. Number two terminal should have a hot whenever the key is on.
This means that I must take my wiper switch and disconnect the hot, and run the unswitched side to ground.
Is this correct, or am I missing something?
Thanks Emmett
 
The wiper motor will work just fine, no matter which polarity you use for the battery. The wiring to the dash switch is the chassis ground side of the wiper motor. The motor gets a hot (either + or -) green wire from the ignition switch, and the other terminal, the one that is grounded by the park mechanism, gets a black wire that runs to the wiper switch on the dash -- and then to ground when you pull that switch.

I can't remember which is which, re: "1" & "2" -- but I know that if you get em backwards, the 35 amp switched side fuse blows, when you turn the ignition key. Check with a continuity tester: which terminal is grounded when the park switch is making contact with the motor cap. That's the switch terminal -- the other one will be for the hot wire. There must also be a ground wire from the motor body to the chassis for this to work.
 
Converting to negative ground should have no effect on the wiper motor (i.e.it doesn't care. Depending on the year of your TR3 the switch is likely switching the ground (green w/ black tracer I think).
 
As I recall, the factory tried the hard mounts for the float bowls, and found that engine vibration could cause enough frothing to make the mixture go lean under some circumstances. Whether you would ever operate under those circumstances is a different question.

The current supply of rubber gaskets seems to be much better than older ones; the ones I took off TS39781LO were almost good enough to reuse. But I replaced them anyway.

Someone, I forget who offhand, is supplying them in polyurethane, which may be the best solution. Try Mark Macy, it might have been him.

Terminal 1 of the wiper motor gets the black/green from the switch on the dash, which grounds the wire to make the motor run continuously. Terminal 2 gets the green wire from the fuse block. Depending on the vintage of your wiring harness, it's either one or two green wires.
 
Randall;
What a wonderful wiring diagram.
I was using the diagram out of the factory manual which shows the switch running a hot lead from the fuse block. That is wrong! The switch switches the ground side, as I suspected. Where can I get a copy of the wiring diagram like you have?
I'll check with Macy on the float bowl bushings.
Thanks a bunch,
Emmett
 
Each edition of the factory owner's manual had a slightly different wiring diagram, to reflect the changes in the actual cars. The first two editions were called "Instruction Book", while the later ones were known as "Practical Hints for the Maintenance of the Triumph T.R.3".

That is a portion of a scan I made from the 4th edition, which appeared to be closest for TS39781LO (probably up to TS50000 or so when the dash rheostat was introduced); then modified with the wiper motor terminal numbers, and the LHD drive connections between the control head and wiring harness. It's still not totally correct, as the fuel gauge connection are shown going to the temperature gauge; and the gauges are not shown in the correct positions. The OD wiring legend isn't quite right either, as of course the switch is not on the steering column; and on my car the relay got power from the ammeter instead of the control box.

Here's a link to the full image.
 
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