Running rougher everyday........

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bendelaurence

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I've got a v8 on carbs which is running noticeably rougher and losing power every day. Anyone got any pointers on what to look for.

So far I'm thinking:

Distributor cap
Fuel filter
Could the carb be blocked?
Fuel pump seems fine
Timing maybe??

Any pointers would be appreciated

Thanks
 
Eyup, i`ve had a vertical learning curve since i got my 3.9...
mines an EFI but this will get you into a fair starting position before you go into owt more involved.
Try these before you do owt else.
1 change oil and filter.
2 put new plugs in. (NGK BPR6ES)
3 get cap, arm and leads from somebody who knows land rovers (not halfrauds or motosave)
3a ensure the firing order is correct (search for Rover V8 Firing Order). You`ll know as you wind throttle open gently up to about 3000rpm cos it`ll get lumpy at about 1500.
4 Make sure the vacuum can is working and there are no vacuun leaks in the system at all.
Are the carbs balanced? (try a search.)
Hope this is some help, dont panic until she stops or you can touch the road with your elbow.
 
bushwwacker said:
Eyup, i`ve had a vertical learning curve since i got my 3.9...
mines an EFI but this will get you into a fair starting position before you go into owt more involved.
Try these before you do owt else.
1 change oil and filter.
2 put new plugs in. (NGK BPR6ES)
3 get cap, arm and leads from somebody who knows land rovers (not halfrauds or motosave)
3a ensure the firing order is correct (search for Rover V8 Firing Order). You`ll know as you wind throttle open gently up to about 3000rpm cos it`ll get lumpy at about 1500.
4 Make sure the vacuum can is working and there are no vacuun leaks in the system at all.
Are the carbs balanced? (try a search.)
Hope this is some help, dont panic until she stops or you can touch the road with your elbow.
Click to expand...

I'm pretty sure the fireing order is correct as it was fine a couple of weeks ago.

I'll get on with the rest though.

Thanks alot mate. I'll keep ya posted.

P.S. Where you from? You talk like you're near me in Barnsley.... lol
 
Just throwing this in as got me stumped for a while. 2 pipes, 1 on each carb, coming from the top a small pipe that goes down the side of the block coming out in the middle of the radius arm area, seems to drain off is a breather. Think my carbs are SU's though.
 
probably the fuel overflow pipes on the SU's. I am just getting to grips with them myself on my new (to me) 72 RRC.

On the holly carb I have no idea, maybee the loss of power is fule starvation?? Hows the pump?
 
bendelaurence said:
I've got a v8 on carbs which is running noticeably rougher and losing power every day. Anyone got any pointers on what to look for.

So far I'm thinking:

Distributor cap
Fuel filter
Could the carb be blocked?
Fuel pump seems fine
Timing maybe??

Any pointers would be appreciated

Thanks
Click to expand...

I'm not so hot on carb engines but do a compression test and make sure you haven't got a head gasket problem. Have you tried using carb cleaner to make sure it isn't just a bit of muck in there?

Failing that check timing, adjust as necessary then run it up and check it again. If the timing appears to wander then you probably have a stretched timing chain. Depending on how old your engine is and how many miles its done, you might need to check for wear on the cam shaft and followers.
 
Thanks to all of you who have advised me so far. I working my way through your points slowly, and have found a v8 expert that can check the bits u carnt for £100.

I have another symptom to report now though.....

Since this morning it has started turning over very slowly and only just starting when the key is turned. Like the battery is nakered.

Could a nakered battery cause rough running and loss of power in a v8 with carbs?? Or is this a completely new problem?
 
I know a very good v8 man if anyone wants his number PM me.

He is well respected on here and has got me sorted a number of times, he is mobile too.

You never know , it could be the battery or a bad earth, try the new battery as you will need it anyway.
 
bendelaurence said:
Thanks to all of you who have advised me so far. I working my way through your points slowly, and have found a v8 expert that can check the bits u carnt for £100.

I have another symptom to report now though.....

Since this morning it has started turning over very slowly and only just starting when the key is turned. Like the battery is nakered.

Could a nakered battery cause rough running and loss of power in a v8 with carbs?? Or is this a completely new problem?
Click to expand...

Not really. It takes much more power to start the motor than when it is actully running. Having said that, it won't help. Is the alternator charging the battery?

From previous posts, it seems you have a Defender with a retro fitted 3.9 with a Holley carb.

I know nothing about Holleys except that they are no good off road. If you intend doing the rough stuff, switch to SUs or if you know anything about 'wiggly amps' retro fit EFi.

Going back to your current problem, have you got electronic ignition or points? What colour is the end of your exhaust (inside:D). The old addage is '90% of carb problems are ignition problems'!

Cheers

Chris
 
Ragtag said:
Not really. It takes much more power to start the motor than when it is actully running. Having said that, it won't help. Is the alternator charging the battery?

From previous posts, it seems you have a Defender with a retro fitted 3.9 with a Holley carb.

I know nothing about Holleys except that they are no good off road. If you intend doing the rough stuff, switch to SUs or if you know anything about 'wiggly amps' retro fit EFi.

Going back to your current problem, have you got electronic ignition or points? What colour is the end of your exhaust (inside:D). The old addage is '90% of carb problems are ignition problems'!

Cheers

Chris
Click to expand...

Hi, yes I will be fitting efi soon just to save some fuel! Lol

And it's ur usual electronic ignition (coil-distributor), I don't think I've ever seen point s in real life :-S

And my exhaust is sooty black on the inside. Although it never smokes or anything like that. Honestly 2 weeks ago it was a perfect runner.
 
start with the basics as pointed out gen ignition parts is the dissy points or amp what condition are the plugs?
 
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