Tb42 missing straight petty carby details inside

Hello all, over the last week my maverick has developed a miss. What i have found whilst the car was running and pulling off leads one at a time is that no4 is not receiveing spark from the dizzy cap. I tried with another lead that i know is getting spark and it did not work . It has new dizzy cap and points new leads and plugs. All the contacts and button look fine to me.

I am a bit lost as to why only one point would not get spark so next step might be the extended button as per other threads.

Any hot tips would be appreciated cheers.

Dont these dizzy's need an extended rotor button ???
Is there an after market electronic ignition available
for these set and forget I say

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Originally Posted by threedogs

Dont these dizzy's need an extended rotor button ???
Is there an after market electronic ignition available
for these set and forget I say

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The electronic ignition module only replaces the points and still uses the rotor button and dizzy cap so if that's where the problem is then it won't fix it. Having said that, I'd still recommend fitting one. I installed the pertronix flame thrower 2 module and coil and it made a noticeable change in the power and economy.

Have you checked the spark plug?

>>>tappin from tassie

Yes all plugs are fine. No spark from dizzy on one point.

Can you borrow another dissy cap to try?

>>>tappin from tassie

I have a brand new dizzy cap. There is continuity between the point inside the cap and the terminal on top where the lead connects. All i can think is my button needs replacing

A combination of extended rotor button, pertonix ignition and points do help.

Have you changed the condenser and coil, as these have been know to cause missfire.

you have done the rest

The most common cause of a miss is the leads /Cap/plugs.

A cracked exhaust just below the manifold can be a cause and loss of powers

a vacuum leak on the inlet manifold can cause miss

a loose carby, can cause a miss. Remove the air cleaner grab the top of the carby and give it a shake


A faulty head or head gasket can be the cause -check the cylinder pressure

Quote:

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Originally Posted by Virgil9

I have a brand new dizzy cap. There is continuity between the point inside the cap and the terminal on top where the lead connects. All i can think is my button needs replacing

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Well it looks like you've ruled everything out but that. Strange for the button to only miss on one lead though. Only thing left to do is swap the button I guess

>>>tappin from tassie

Yer i think ill just add the 4mm onto my button or buy the extended rotor next. Thanks for the help

I dont think the extension is 4 mm, its around 2mm. I have heard of people extending their existing button. The main improvement is bettle idle, an the motor is a bit more responsive.

I don't think the rotar would be the route cause.

Could you have a bent dizzy shaft -I have heard it happening but don't know what the symptoms were

Or a worn 4th lobe on the dissy shaft.

I guess they came from factory with that length rotor button and not missing so you'd think there's another issue away from the length of rotor button... But they can be a little bitchy lol...comes down to swapping bits which luckily is not too expensive

>>>tappin from tassie

Ah are there any ways to see if it is a worn 4th lobe?

Remove the dissy and use a feeler gauge to check the gap when on the fourth cylinder.

>>>tappin from tassie

Food for thought, cheers.

Ok all found the problem. The lobes were not lubricated so the breaker block was worn causing the point in the dizzy not to open on the 4th lobe. I adjusted and lubbed it up. Working perfect. Thanks all for the tips

Great to hear it's fixed mate.

>>>tappin from tassie

Yes its running great. Love the tb

Glad you got it going. Thanks for the feedback, as it might help others.

I suggest you consider upgrading to pertronix, as there are no moving parts to wear out