Nearly there...help please.. CO level..

[branty]

Hi
I would really appreciate some help for a final push to get my R4 back on the road.

My 1984 gtl went for MOT today and so nearly made it- no rust, just 2 faults.

1. The horn only works with the lights off. I paid a large sum > £3,000, to have it restored 3 years ago and it seems that the wiring may have connected the horn to the lights. Any ideas please?
2. Carbon monoxide level 10.5% ; max 4%. The nice chap said it was warned up and suggested a carb or timing issue. Any ideas how to approach this would also be appreciated...
Thanks
Branty

 

[André4Renaults]

The horn not working with the lights off sounds like either:
1/ A poor earth, preventing enough current getting to earth when the lights are on, or:
2/ A fault in the switch not passing power to the horn when the lights are on.

That CO level is HIGH! I would check the mixture screw is not too far out first, before looking at other things. Before I go any further, howw au fait with carburettor adjusting are you?

 

[retrospecparts]

A simple quick check, re the exhaust emissions: Is the choke is actually returning to the fully off position, when the cable is pushed in?

 

[branty]

A simple quick check, re the exhaust emissions: Is the choke is actually returning to the fully off position, when the cable is pushed in?

Thanks to you both,
It is high and there are other issues I think are related to the Carb such as poor hot starting and slightly lumpy running. The choke does go all the way in.

I will try the idle mixture screw first- fairly au-fait with carburettors being of an age when doing your own mechanical work was the only way to stay on the road with limited funds as a youngster!

Will also look at the earths..

Brandy

 

[mojobaby]

Hi Branty, what retrospec means is that when you push your choke control all the way in, you should look at the choke flap at the top of the carburetor. It should be in a complete vertical position. If its not, then loosen the screw that holds the cable and hold the cable with a pair of pliers so that it can't move and then physically move the choke flap until its completely upright, then tighten the screw again.

As per Andrew's suggestion, my mixture screw is 2 and a half turns out and I passed with a 4,20 reading.
Give your air filter a good clean as well.

 

[branty]

Hi Mojobaby
Thanks- yep checked choke is vertical.
I have a Zenith carb and have identified the mixture screw. Looking at other helpful entries in the forum, it seems that you can screw it right in during the test and reduce the CO. I also read in the Haynes that the car should be run at 2,000 revs ideally before the test, not just warmed up on idle?

I have screwed it in now and taken it out 1 full turn so we shall see. Will clean the air filter.
The garage is quite old care friendly and I will take it back in now all the others are sorted including the horn and hopefully play around with the mixture screw and monitor the CO.

Will feed back...

Thanks all

Branty
PS no criticism of the garage who did the restoration work discussed above intended