TB42 Carby Rough Running an Comedy Backfire

[waflyer]

Hi all,

Well I finished my auto gearbox rebuild as documented on here and that's running all good. However, the old carby TB42 is acting up a bit.

It's done 157k so not a lot for 22 years old. However on wet days (yes - we have them in Perth ;)) it acts up: misfiring and the occasional comedy canon-like backfire. Doesn't tend to occur on dry days...

I'm thinking ignition system. No idea on the general condition of the current ignition components. What I do know (from going through receipts since original purchase 22 years ago) is it is all original (minus plugs)!

The plan is to do a full strip down and renew of the ignition system and check/reset the timing. What do you all recommend component wise? Electric ignition module? Brand of plugs/leads etc.?

All suggestions much appreciated. As I do the work I will post up bits of info in terms of how-to and the impact of everything I replace to help others along as I'm learning that this issue is common for the TB42's!!!

Cheers,

Sam

[97_gq_lwb]

Common is noise suppressor and condensor failure .
also pertronix ignition upgrade search pertronix you'll find a few helpful threads on the install.

[threedogs]

I would think electronic ignition would be the go, just set and forget. Don't buy those thick Blue style leads you dont need them Bosch make great leads

[davo94]

I have the same back fire problem. All ignition system is new. Has petroex. It plays up on gas and petrol.

[97_gq_lwb]

disconnect the noise suppressor run a dedicated relay for the coil power supply and check the resistor on the coil if your running one.

also check all connections especially earth connections.

[Robo]

disconnect the noise suppressor run a dedicated relay for the coil power supply and check the resistor on the coil if your running one.

also check all connections especially earth connections.

std power wire to the coil is undersized or poorly designed and or suffers power lose?.

[97_gq_lwb]

Yes even the ignition switchblock has been known to wear out and give trouble as well

[GandalfWhite]

If its damp conditions related maybe try degreasing/cleaning around coil lead, distrbutor cap and SP leads. Checking at night can sometimes show sparking. Check all connections around coil and earth connection on the motor . A timing light is an easy way to see an intermittent fault. All of the above are definite possibilities which can sometimes make this problem a pain in arse.

[taslucas]

BUMP...
Well instead of starting a new TB42 carby related thread to join the growing number, I thought I'd just bump this one.
My TB42 has been getting ever so slightly down on power in the last few weeks (just received pertronix2 and coil in mail).
Last night the old girl got real bad real quick. Will start fine and rev up but does not want to stay there idling. I have to keep feathering the throttle as the revs will just die down and stall. Occasionally it will idle with the hand throttle pulled out(but only up around 1500 rpm-- used to idle around 700 beautifully till yesterday) but then if I put it in drive it dies straight away unless I feather the throttle. It'll drive fine for about 1 minute then die. Feels like a fuel blockage?
I got a new filter this morning and fill fit that and have a look at carb this weekend. (carb was completely rebuilt about 18 months ago and been running sweet till yesterday).
What other things should I look for???
Help me because at the moment IM DRIVING A PAJERO!!!! Lol

Tap, crackle, pop

[waflyer]

Forgot I started this thread! Anyway last weekend, I stripped down my carby and fuel system as the backfiring and missing was getting to the point that I felt it might be terminal - as in I might kill it!

Turns out there were a nummber of things wrong. Various jets in the carby were blocked, the fuel filter was bunged with bits of the Pilbara and the timing was full 15 degrees out (actually set to 5 to go in so we will see if that makes any difference.

Best of luck with fixing it mate, but my guess is filter and jets will be the root cause of your troubles.

[taslucas]

Best of luck with fixing it mate, but my guess is filter and jets will be the root cause of your troubles.

Cheers mate, I have a new filter I will try this weekend.

Tap, crackle, pop

[Robo]

BUMP...
Well instead of starting a new TB42 carby related thread to join the growing number, I thought I'd just bump this one.
My TB42 has been getting ever so slightly down on power in the last few weeks (just received pertronix2 and coil in mail).
Last night the old girl got real bad real quick. Will start fine and rev up but does not want to stay there idling. I have to keep feathering the throttle as the revs will just die down and stall. Occasionally it will idle with the hand throttle pulled out(but only up around 1500 rpm-- used to idle around 700 beautifully till yesterday) but then if I put it in drive it dies straight away unless I feather the throttle. It'll drive fine for about 1 minute then die. Feels like a fuel blockage?
I got a new filter this morning and fill fit that and have a look at carb this weekend. (carb was completely rebuilt about 18 months ago and been running sweet till yesterday).
What other things should I look for???
Help me because at the moment IM DRIVING A PAJERO!!!! Lol

Tap, crackle, pop

Had a similar problem.
decel device on carb was blocked up.
needed a good clean out slight adjustment and good to go again.
3 yrs ago and still good.
cheers

[taslucas]

cheers Robo, PM received

[waflyer]

Since replacing the fuel filter and cleaning hte carby jets the old truck is running much better. Pertronix kit is next. I will report back if there is further improvement...