I assume you have overhauled your carburettor?

 

nope, just split it in two, little cleaning...

Well I would be looking at cleaning it properly, blowing out all passages and fitting an overhaul kit before I got carried away with anything else.

Well I would be looking at cleaning it properly, blowing out all passages and fitting an overhaul kit before I got carried away with anything else.

 

It's not worth it as I have a 32/36 Weber to go in! I don't think the 3 cilinder problem has anything to do with the carb

I'm not convinced it's actually running on three cylinders. What are you basing this assumption on. You say the plug in cylinder 3 is dry. If it wasn't running it should be wet (unless the inlet valve is completely closed. A key clue to me is the fact that it ran correctly briefly after it backfired through the carb.

 

Why not fit the weber then and see what happens.

 

You still haven't given us any outcome of the compression test. Don't try and over think it. The cause is likely to be a simple one.

 

Back to basics: spark, fuel, timing, compression.

EDit - didn't read whole thread , disregard

Edited January 26, 201610 yr by ms85er

I'm not convinced it's actually running on three cylinders. What are you basing this assumption on. You say the plug in cylinder 3 is dry. If it wasn't running it should be wet (unless the inlet valve is completely closed. A key clue to me is the fact that it ran correctly briefly after it backfired through the carb.

 

Why not fit the weber then and see what happens.

 

You still haven't given us any outcome of the compression test. Don't try and over think it. The cause is likely to be a simple one.

 

Back to basics: spark, fuel, timing, compression.

 

I thought I had posted the values here.

 

1 - 12,5 bar

2 - 12 bar

3 - 12,75 bar

4 - 12,5 bar

 

When I take spark lead in each cilinder I can notice the engine working differently. But this doesn't happen with cilinder 3. It just works as it was before, with lead or no lead...

 

I'm gonna replace dizzy cap and rotor tonight and see what happens...

Take each spark plug out, one at a time. Put it in its spark plug boot and sit it close to the engine block crank the motor. and get it to arc. You will see the little spark, might help if it's darker or shaded. Next when your confident that all your spark plugs are working, Dissy is firing on all 4 report back

Take each spark plug out, one at a time. Put it in its spark plug boot and sit it close to the engine block crank the motor. and get it to arc. You will see the little spark, might help if it's darker or shaded. Next when your confident that all your spark plugs are working, Dissy is firing on all 4 report back

 

Did that already, all of them have spark, switched cables and spark plugs to see if the problem moved to other cilinder but it's always number 3. On number 3 I took the cable out with a rubber covered clamp and still got shock in my finger...

About the spark colour I can't tell anything.

Replaced dizzy cap and rotor, nothing...

The car is hard to start, few stalls before it could keep the idle, working on 3 cilinders keeps RPMs stable for a minute, then starts floating until it stalls...

Is the anti dieseling(??????) solenoid connected? If it isnt getting power when the engine is running, it will cause running issues - rough idle, stalling etc.

 

My 5K idled rough with the standard 3k carby fitted. Ran fine but would rock the whole car at idle. Got lots of looks sitting at lights - people were asking what the hell was in the car...... When we switched to the factory twin carb set up, idle smoothed out. Did not touch anything else.

I've been running 4K carb for a year with no problem.

What solenoid is that??

Its the rectangle looking thing in the bottom left of the pic.

So you have compression. That suggests your valve train is working as it should and valve clearances can't be too bad. Presumably that clears the doubt about lifters? It sometimes runs properly so the cam timing must be roughly right. You have spark.

 

Does No. 3 plug get wet or is it dry. If that cylinder isn't working, the plug should be wet with fuel. If it isn't, where is the fuel mixture going?

 

If it's dry, is there some sort of obstruction in the inlet runner or exhaust on that cylinder? I would still be rebuilding or swapping that carb and replacing the plugs.

A friend lended me a 3K carb.

The engine works as it should!!

I can't get it to idle without throttle help, but it doesn't bounce, looks pretty decent. Now I just need to adjust the carb so it can move

That's great news. Fingers crossed it continues running right.

 

Be aware that the weber will need proper setting up to get it running better than the carb you already have. Unless you are planning changes to cams, headwork etc, I would suggest staying with the 4K carb (properly rebuilt). Otherwise you may find all you add is reduced driveability and poor fuel economy.