Engine power loss

[moremonkey]

For the past several years I've had a recurring issue with my BN1 that only happens when running in third gear with RPM over 3,000. Because I generally don't find myself in that situation, I ignored the problem. But when the overdrive stopped working reliably last summer (just fixed), it became more of an issue.

Anyway, now that I am working my way through winter repairs, I thought I would see what the collective wisdom of the Forum has to say about this.

As I said, when the engine runs above 3,000 RPM for any sustained period, the engine will abruptly lose power and sound as if it fouled a plug. The car will struggle and fail to maintain its speed, even with WOT, make kind of a sick burrrrblllll from the tailpipe, and feel like it is running on less than all four cylinders. If I put the clutch pedal in and let the engine drop to idle speed for a few seconds and then blip the throttle, the problem cures itself and won't come back unless I take the RPM back up over 3,000 again under load.

Other than this specific situation, the car runs great.

Any ideas what's going on and how to fix it?

 

[Keoke]

Check carburetor float condition and levels.

Check Fuel pump deliver rate

Check air filters for lack of flow.

 

[CLEAH]

Sounds like fuel starvation to me, which can be caused by a blockage, air getting into the fuel lines, floats as Keoke says, etc. In general, that is a situation where the engine is using up the fuel available to it faster that it is being replaced by the system. It is amazing how a fuel delivery problem can seem like a fouled plug.

 

[BoyRacer]

Sounds to me like a an inline fuel filter may be the culprit. I have had two occasions over the years where I have had exactly the same symptoms you describe. In both cases it was an inline fuel filter that was limiting the amount of fuel at higher RPMs.

 

[pkmh]

Yep, sounds like a fuel issue. Everything above mentioned and even possibly fuel tank, filters. Mine would just quit which turned out to be the fuel pump being clogged from a rusty fuel tank. Yours problem sounds different, though. Maybe running a constant fuel flow test by removing the line after your in line fuel line (if you have that set up) to see if a good, constant flow still occurs. Easy tasks first. That and then trying new filters, then check your floats. Wouldn't hurt to also clean up your electrical connections to your fuel pump.