Engine not sounding right

[Chaz23]

Due to problems this morning I ended up going into work the 7 this morning - well at least the weather was good. However the engine was not sounding correct.

 

I did not seem to have its full power and it sounded like it was clogged up (or something was clogged) it tried to missfire a few times but did not. I have had this a few times before when starting it from cold but normally is fine once I have got down the road. Any ideas what I should look for to find out what is up? Sorry my experiance of engines is limited but I am a quick learner.

 

Oh yeah it is a 1700 Supersprint and it is sitting at work (hopefully the little kids are not trying to sit on it this time).

[Big Brother]

There could be lots of things causing your problem.

 

I'd start by checking that your carbs are balanced and that your idle mixtures are OK.

Then I'd be tempted to check that the plugs and leads are OK (and dry)

Also don't forget to check your valve clearances.

 

Steve

 

 

SE7EN-UP!

-----_{When a schizophrenic threatens to commit suicide, is that a hostage situation?}-----

 

[Chaz23]

Leads I can check before leaving home.

 

Carbs and mixture I just need to RTFM (Which I do have).

 

Valve clearances? You lost me on that one.

[Manxseven]

Chaz,

 

When did you last use the 7? Was it wet?

 

Check inside dizzy cap and maybe the air filters are damp??

 

 

 

 

Caterham Fireblade here

[Chaz23]

Last Monday (I think) definatly not raining when I last used it but could be condenstion as it has been in the garadge since I last used it and the temputre has drop a bit since then.

 

Dizzy cap great that means a nightmare of a job - air filters seemed OK last time I looked at them (2 weeks ago) but will check again.

 

Oh thanks for the help with this guys.

[Steve Cornford]

Hi Chaz23,

When I followed you to Toyota, engine was sounding ok, but not smelling ok!

You were burning something other than petrol methinks?

 

 

Sigma Steve

[Chaz23]

Right better check the mixture and stuff then.

[Big Brother]

Info on checking and adjusting idle mixtures can be found here

Look for the heading "Setting the Idle and slow running " (about 2/3rds of the way down the page)

 

Steve

 

 

SE7EN-UP!

-----_{When a schizophrenic threatens to commit suicide, is that a hostage situation?}-----

 

 

Edited by - Se7en-Up! on 24 Jul 2007 13:04:25

[Chaz23]

Thanks for that Se7en-Up!

 

A reasonable idle speed for a modified engine on Webers is between 900 and 1100 RPM

- think that might be my problem as my idle speed is not that high - have always thought it was a bit low but as it seemed to run OK thought it was correct. Will have to check it.

[Chaz23]

Thanks guys.

 

Well checked the leads for the plugs and one of them was very iffy - fixed it for now but might have to buy some new ones. Car sounds better than this morning but still have a few things to check.

[Graham Perry]

You might also want to check that the throttle cable hasn't got too much slack and as a consequence the butterfly's are not fully opening in the carbs .

 

After that you are into the dizzy having slipped a few degrees (not impossible if its not tight) and the advance not being enough.

 

Also I don't know what set up you have but rotor arms used to fail on the standard Caterham supplied Lucas dizzy where the brass arm would work loose from the plastic/metal body and could cause very rough running so you might want to check if the rotor arm isn't about to fall into bits. I had a couple of these fail in the past

 

 

Edited by - Graham Perry on 24 Jul 2007 22:10:39

[KeithT]

I had a similar problem with my Super Sprint last week. The engine sounded different to usual and developed a misfire.

As there were one or two other issues I decided to leave it at Millwood for them to sort.

During the short drive I thought the misfire was so bad might have to stop. Then it seemed to clear and, as far as i can tell, was back to normal.

Be interesting to see what Millwood have to say.

Keith