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TR2/3/3A Tr3 bogging

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prb51

prb51

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Gents, Recent development, car starts and idles fine, runs well if I accelerate slowly but if I punch it or 'step on it' I get a flat spot/bog. The car will run fine a 70+ mph if I arrive at the speed slowly. New fuel pump about a month ago. Suggestions. Pat
 
Put some 20 wt oil in the carb dashpots. About 3cc's worth. Pull the caps on top, remove the cap with plunger attached, put in the oil, replace caps.
D
 
This was also an issue with my Dad's TR3A. I check the dashpot oil level before every trip now and when it is full the hesitation goes away.
 
Check the dist advance weights under the point plate. this is a very neglected area and a problem here will get you a tow bill. The other symptom will be a back-fire when you turn it off(just before failure)At todays gas prices, a well oiled dist. is a must!!
MD(mad dog)
 
Guys, It ain't the dash pot oil, checked and at the correct level. I would normally guess a gas restriction but if that were the case it shouldn't run at the higher rpm's as it does.
 
Not a very expert opinion - I had the same symptons happening on my 6 and could fix that by

a) setting ignition to specs (points, static timing)
b) tweaking the carbs
c) tweaking the ignition by ear

PS: I assume MD's clue is worth more than a glance...

Joerg
 
On my old MG's vacuum leaks would cause the same problems-- Haven't had that as a concerns yet with my TR3
 
Sometimes a bogged motor can be caused by rich carburetion. Have you swapped needles/rejetted? I'm not familiar with TR3's, are you using SU's?
 
Hi Pat the bogg down problem is probably ignition. Flat spot in coil or condenser possibly developing which would not permit the capacitance to built and discharge fast enough-- naturally that is if you have stock ignition. However, once I had a similar problem with my tr3 and it turned out to be the link had come lose between the carburetors. The car would run fine off the one carb if I just took it easy-- like you were commenting.

George
 
you also might want to pull each wire one by one and make sure that you are firing on all cylinders. I recently had two wires switched and had a "bogging" feeling - i never got it up to 70 but I imagine it would have been possible on a flat road.

I also had similar symptoms years ago and found that one of the needles had dropped into the jet and I was running on one carb.
 
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