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power loss
Posted: Thu May 18, 2006 5:10 pm
by devildad
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.
Posted: Thu May 18, 2006 8:15 pm
by paso750
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
Posted: Thu May 18, 2006 8:21 pm
by paso750
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)
Posted: Thu May 18, 2006 9:12 pm
by ducapaso
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...
what is the filter at the petcock?
Posted: Fri May 19, 2006 2:08 am
by devildad
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.
Posted: Fri May 19, 2006 4:41 am
by delagem
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.
Posted: Tue May 23, 2006 8:42 pm
by ducapaso
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.