power loss

devildad · Post by **devildad** » Thu May 18, 2006 5:10 pm

Engine starts fine and runs for about 20 min, no problem. It then backfires a few times and looses power. If I let it sit it starts fine and runs for about 20 min. Any thoughts would be appreciated.

Post by **paso750** » Thu May 18, 2006 8:15 pm

spark plugs are clean, fuel filter is not clogged (the one of the petcock also), valve clearance is ok, carbs synched and the rubbers of the inlet manifolds ok ?
This would be the first things I would check. As the issue does not appear from the start it could be that something cloggs and the engine does not get enough fuel, but as there`s backfiring it might have to do with the engine/carbs and all other parts getting warm. This could speak for some airleak. Check if everything from the airfilterbox down to the manifold/cylinder is tightened well and take a closer look at the rubber parts.

Gerhard

Post by **paso750** » Thu May 18, 2006 8:21 pm

thinking of it, if it loses power it seems that one cylinder drops out. Usually the front one (for whatever reason). Do you have a spark ? Do you have problems with your battery (regulator) lately ?

If it looses power after some time and you open throttle, does the power come back (and the sound) ? (sorry a stupid question, but some people cannot "hear" if an engine is running on both or only on one cylinder)

ducapaso · Post by **ducapaso** » Thu May 18, 2006 9:12 pm

Have a look to the ignition wiring (both low and high voltage) a loss of this kind can also happen because of an ignition coil failure (in the downloads you'll find how to test them)
I think this sould not be a fuel trouble, as the engine just "shut" when the fuel is off.
In the very next minutes after starting, the engine is powerful in 5 gear or it looses power over 6000 rpm ? this is tipical for spark plugs gone
i'm waiting for your reply...

devildad · Post by **devildad** » Fri May 19, 2006 2:08 am

is there another filter? I replaced the one before the fuel pump, thought it was the culprit. all else is ok, no problems with battery or rubber.

delagem · Post by **delagem** » Fri May 19, 2006 4:41 am

Sounds like a classic fuel starvation problem. Possibly a kinked fuel line?

The next time it loses power, try opening the gas cap and see if that makes a difference. Sometimes the tank will cause a vacuum and starve the engine of fuel. Does anyone know where the air inlet is on a Paso? Probably in the cap.

If it does it at idle, try pulling the tank, and make an auxiliary fuel tank ( a mustard bottle and some fuel line works great!), hang it up high, and bypass the fuel pump. This will eliminate the fuel pump; if the problem doesn't reappear, it's the pump.

I know nothing of repairing the pump, I eliminated mine and it works fine without it.

ducapaso · Post by **ducapaso** » Tue May 23, 2006 8:42 pm

there's a small metal tube insede the tank (you can see it spoiling under the tank or opening the cap: it runs across the tank to its upper part) and this provides to air pressure balancing inside the tank... Maybe the engine can run also without fuel pump, bypassing it... I never tryed to do, but it should require a full tank.

power loss

power loss

what is the filter at the petcock?