• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

TR2/3/3A TR3 Running Rough Again?

karls59tr

Darth Vader
Country flag
Online
I had Jeff at Advance dial in the Petronix dist in the Spring and that solved the black carbon fouling on the plugs.Car ran great all Summer idled great and pulled strong with a steady exhaust note.Recently I had let the gas in the tank get too low and rusty gunk clogged the filter....changed filter and blew out the line to the tank.Ran better but still running rough. Car has been running with a bad miss...runs rough on acceleration....better at idle....the plugs are badly carbon fouled again? There is a a bit of gas seepage near the jet area of the front carb(maybe the seal)? I'm wondering if some crap got past the gas line filter...past the electric fuel pump??? and into the front carb? Also am wondering if the dist rotor(has a nick in it) and cap contacts (which look less than new) might be complicating the issue? Only a few months on those? Or is it the dreaded Petronix malfunction? Any advice on how to isolate the problem?
 

Moseso

Jedi Knight
Offline
Your black plugs suggest mixture too rich -- not what one would expect if you have gas tank crud impeding fuel flow somewhere -- UNLESS -- crud in the float needle valve is preventing the valve from closing. Do you smell fuel while driving? Is there evidence of fuel coming out the top of the float chamber?

Alternatively, black plugs indicate retarded timing. Check that, of course. It doesn't sound like your cap/rotor would play into this much...
 

TFB

Jedi Knight
Country flag
Offline
not a tr expert but have experience with Su's .Have you pulled the domes off to clean and check,or lifted a piston to see if it drops back with a click with damper out.Just a thought.
Tom
 

sp53

Yoda
Country flag
Offline
Not sure exactly Karl, but it sounds like from what I hear that Jeff would know your situation best because he does that stuff every day. Having made that disclaimer, what I would do is keep a manual set around for comparison. I never used the electronic stuff, so I am not sure how difficult it would be to swap that around, but I speculate it would not be that difficult. Moreover it sounds like one needs a stock set for back up anyway. I doubt if any crud got past the filter because the crud would have clogged it first. I have had small pieces of stuff get into the jet assembly because I use the stock set up with just those brass screens for filters when they plug that that usually stops the fuel deliver, not letting the car start. But it is possible for a small piece to get through and hold the jet open and flood the system causing fouled out plugs. That is an easy fix by just lifting the bowl top off and pull out the jet and gently blow out the crud. If you have an electric fuel pump, and it is turned up past say 5 psi that can push too much gas in also. The SUs only need like two pounds of pressure. The reverse of that is. Have you tried driving up a hill and see if you run out of gas as the bowls go dry? However, there is an old sports car saying that what is wrong with your SU carbs is your Lucus distributor.

Steve
 

TR3driver

Great Pumpkin - R.I.P
Offline
Oddly enough, I was just looking at the same problem. Apparently, enough fine grit had gotten into the carb jet to erode the jet seals and cause them to leak, both out the bottom and into the carb throat.

So my suggestion would be to address the jet leak first, and see what that does for the rest of it. Of course, once you've had the jet apart, you'll need to reset the mixture anyway (which is the most likely cause of black plugs).

Another possibility worth investigating is whether the jets are returning up against the mixture nut after using the choke. It's not uncommon for them to stick down and cause extremely rich mixture. You can check by just pushing on the bottom of the jet. If it moves into the carb body, that was the problem.

If so, I suggest using some sort of polish to bring the surface of the jet to a shine. Original jets were quite smooth from the manufacturing process, but modern replacements are supplied much rougher, which can cause both rapid seal wear, and jet sticking. Ordinary toothpaste makes a suitable polish, or auto body polishing compound. Or pretty much anything sold as "metal polish". I tried some Mequiars Billet Polish this time, which worked about as well as polishing compound (for about 10 times the price :laugh: )
 

hondo402000

Darth Vader
Offline
if all was well untill you sucked crud from the tank I would say its all related to the crud getting thru the system and into your carbs, I would not touch anything else till you cleaned the entire fuel system out including the carbs,float bowls,seats,. Once that is done and you still have the problem then move to other systems, if you have crap in your fuel tank, best to take the tank out, clean it up, seal it too, other wise you risk doing it again

just my opinion

Hondo
 
OP
K

karls59tr

Darth Vader
Country flag
Online
The problem was twofold: 1)AS Randall suggested the the jets wern't returning when I used the choke. 2)I actually had a bad spark plug in the #3 cylinder!....replaced the plug and all is well again. Thanks to all for their advice.
 

TR3driver

Great Pumpkin - R.I.P
Offline
Glad to hear you got it sorted, Karl.

karls59tr said:
I actually had a bad spark plug in the #3 cylinder!
A common side effect of mixture problems. Crud builds up on the plug, and then sometimes when it gets hot, it melts to form a conductive 'glaze' that can keep the plug from firing. Particularly frustrating when it only causes a misfire sometimes (like under load).
 
Similar threads
Thread starter Title Forum Replies Date
T TR2/3/3A TR3 Running Rough - Cause[s]? Triumph 8
M TR2/3/3A Another rough running TR3 Triumph 1
T TR2/3/3A TR3 running rough Triumph 6
R TR2/3/3A TR3 Missing [running rough not stolen!] Triumph 4
K TR2/3/3A TR3 Running rough..Cam or Carbs?How to diagnose? Triumph 10
T TR2/3/3A Anyone running tubeless radials on TR3 steel radials? Triumph 2
K TR2/3/3A Who is running a Sleeved Thermostat in their TR3? Triumph 16
K TR2/3/3A Anyone running an Oil Temp sensor on their TR3/4? Triumph 11
tinman58 TR2/3/3A TR3 running HOT Triumph 38
martx-5 TR2/3/3A TR3 Running Hot Triumph 15
newmexTR3 TR2/3/3A Oil pressure running high - TR3 Triumph 6
K TR2/3/3A "Cool running"...Hottter plug? TR3 carbon fouling. Triumph 11
RedTR3 TR2/3/3A TR3 Front Carb Running Rich Triumph 13
bluemiata90 TR2/3/3A Normal running temp for TR3 engine Triumph 10
S TR2/3/3A Running Temperature of TR3 Triumph 6
martx-5 TR2/3/3A Anyone running 6" wires on TR3?? Triumph 15
txtr3 TR2/3/3A TR3 hard starting, but has been running ok Triumph 11
Mickey Richaud TR2/3/3A TR3 Running Hot Triumph 18
T For Sale Free - Body Jig for TR3/TR3A Triumph Classifieds 0
J TR2/3/3A TR3 engine cylinder top clearance Triumph 22
BillyB62 TR2/3/3A Looking for the Owner of a TR3 Triumph 5
Pool Dad 1960 TR3 engine serial number Triumph 14
T TR2/3/3A TR3 coolant hoses Triumph 2
T TR2/3/3A Has anyone designed a hand brake warning light for the TR3? Triumph 3
J TR2/3/3A "TR3" painted on the engine block Triumph 13
J TR2/3/3A TR3 Rear seat Triumph 11
D Socket for TR3 Gear box drain plug Restoration & Tools 6
J TR2/3/3A TR3 gas tank mystery Triumph 5
T Wanted Wanted - 1956 TR3 Crankshaft Triumph Classifieds 0
jfarris TR2/3/3A Venture into the "dark side," Miata seats in a TR3 Triumph 2
T TR2/3/3A Question on old radio from my TR3 Triumph 9
T TR2/3/3A tr3 front carpet replacement Triumph 5
T TR2/3/3A Should there be a body ground strap to battery on TR3 Triumph 7
G For Sale: Triumph TR2, TR3, TR3A Sheet Metal Body Parts – Front Apron (valence) with grille, Bonnet (hood), Doors, Boot (trunk) Deck Lid Triumph Classifieds 3
G For Sale: Triumph TR2, TR3, TR3A, TR3B Factory Steel Hardtop, New Rear window, Partial Bracket Set Triumph Classifieds 2
A TR2/3/3A Early TR3 starter (bomb style) bushings sizes Triumph 5
T For Sale TR2 - TR3 Gas Cap for sale Triumph Classifieds 1
B TR2/3/3A TR3 Hard Top Triumph 2
D TR2/3/3A TR3 throttle linkage bell crank. Triumph 13
M TR2/3/3A Defective master cylinders Tr3 Triumph 13
BarryO TR2/3/3A setting up a TR3 clutch slave Triumph 5
M master cylinder brake/clutch Tr3 Triumph Classifieds 6
C TR2/3/3A TR3 Gearbox Problem Triumph 10
Tr3aguy TR2/3/3A Started a Car revival channel for the TR3 Triumph 12
J TR2/3/3A Any advice for new floor install on my TR3? Triumph 9
D 1957 Triumph Tr3 Triumph Classifieds 2
P TR2/3/3A tr3 side curtains Triumph 4
banjojambo Triumph tr3 vertical link wobble Triumph 2
S TR2/3/3A purchased a box of tr3 parts this weekend, Triumph 1
C TR2/3/3A TR3 close by Triumph 2

Similar threads

Top