Thread: 3.5l Carbs V8 loss of power

Have these symptoms just appeared, got worse gradually, or is it a vehicle that is new to you?

If everything else checks out, have you have the carbies rebuilt or even tuned? If it has the originals on it, they will go out of tune quite quickly. Mine seem to need a tickle every 6 months or so, or the thing runs like a pig. I have yet to convert mine to something more suitable - again, just another job that is on the 'to do' list...

Thanks for your answer.

The loss of power appeared after I did around 400k's in Fraser and I noticed it as soon as I got back on the mainland. Since then I've done more than 2000k's and if anything it has gotten slightly worse.

I'm pointing to the carbies also now. We'll try and see if it's something I can do or I'll have them checked.

Cheers,

Had similar issues with an '81 Stage One that i used to own. 1 carby was a bit out of whack (from memory each carb feeds 2 cyls on each bank ) and the vacuum advance diaphragm had **** itself therefore no vacuum advance. I'm not sure which happened first but I know with both combined it was a pig to drive. When everything was Mickey Mouse it was .

Forgot to mention that I checked the vacuum advance and it seems to work (when I put pressure on the tube it turns on the distributor).

All seems to indicate the carbies so far.

Thanks for your answer.

The change of engine note is likely when one carby is not functioning. I would suggest replacing the fuel filter first and foremost, also checking the rate of fuel delivery from the pump. Check also the carbies aren't flooding, there may be dirt in one carby inlet causing the float bowl to overflow.

G`day ,

if mine and running CDs i`d first check for oil in the dash pots and then the diaphragms for holes .

When or if you take the tops off i`d suggest checking the pistons move freely and the needles are attached , screws are tight ETC also note which direction things face .

Sounds like one carb is not working and the sooty plugs may be that the one working is over fueling to keep pace .

If flooding as suggested it may run well at high revs and poorly at low .

Peter

i have known ehxaust mufflers to collapse internally and limit flow, causes a big loss of power and a different exhaust sound. might be worth checking

Hi RuiF1,

Is she hard to start and lack of acceleration?
I agree with PLR check the oil in the dashpots and check for a minor hole in the diaphragms.
I had an issue recently with my 81 rough idling, lack of power and it turned out to be one of the Diaphragms.
What's annoying I'd checked them .....but not close enough as it was a very minor tear

Baggy