Engine Problems!

[Rhino1]

Hi

I was wondering if any one can help me with the problem i been having on my trike with a rotax 582 not blue top. A little history of what i have done i have replaced all fuel pipes cleaned out the tank removed carbs and stripped and cleaned retuned them Removed and replaced spark plugs.

I then fly the aircraft with no problems 3 hours of good flyin then all of a sudden the engine goes to idle. Open throttle engine remains at idle, pull choke no cahnge, put fuel pump on no change egine remains at idle. I land with engine at idle stop and i open throttle and engine gets full power. Cant fault engine on the ground done extensive gnd runs cant get it to do it on the ground. The plane will then fly for maybe another 2 -3 hours then do the same thing there is no time cosistant when it happens last one was 3 min after take off down wind. Im flying up in zim alt 4600 ft the day was clear no clouds

Checked all fule sysytem no contaminents have no idea whats happening with this has any one got any ideas would really appreciated the help

[weedy]

Hi, in the past I had a similar problem and found the fuel tank breather block, so as the fuel level dropped a suction was created in the tank.

[John Young]

Seen the movie too many times ...

[V]

The general wisdom says that if pulling the choke at any throttle setting makes no difference to the motor, then the problem is likely to be electrical.

Cheers,

V.

[Tailspin]

It also sounds like a blocked Vent pipe to me.

[John Young]

The general wisdom says that if pulling the choke at any throttle setting makes no difference to the motor, then the problem is likely to be electrical.

Hi V,

I stand to be corrected but -

Electrical will either be 100% or stone dead.

Fuel starvation will dampen the effect of the enricher.

There are known cases where the silver top just gets tired after running for an hour or so but for now i will go with lack of fuel supply.

It could of course be a blocked breather of gunge in the elbow from the tank - here just pull the pipe off and look for a good "pee" of fuel.

Regards
John

[V]

Hi John,

you're perfectly right, electrics have little to with the throttle on these engines. However, this Mike Stratman article stresses the point of the 'choke circuit': http://www.800-airwolf.com/pdffiles/ARTICLES/part2.pdf He says that when you experience a problem during flight, apply the choke. If the problem gets worse, it is probably a fuel-rich engine. If the engine responds favourably or speeds up, the engine wants the fuel, indicating a too lean condition at this rpm. If applying the choke does nothing, it is likely a electrical problem.

Of course, one always has to look at the whole system. I just thought, based on the description it is unlikely to be a carb icing problem and since the choke, turning on/off the auxiliary fuel pump make no difference and the engine repairs itself in the ground, without anyone cleaning anything, it's an idea to check the electrics for gremlins. rhino1 also mentioned that the problem might occur as soon as 3 minutes after take-off - that sounds a bit too quick for pressure build-up in the tank that can not be countered with an auxiliary fuel pump.

Cheers,

V.

[kloot piloot]

I would go with weedy and John on this one. Also check fuel pump membrane, since you are talking about a "not a blue top 582". Could have a pin-prick hole in it.

You replaced pipes. Check for small rubber filing stuck at jets or elsewhere.

[Duck Rogers]

There are known cases where the silver top just gets tired after running for an hour or so

Also check fuel pump membrane, since you are talking about a "not a blue top 582"

There's no difference between a Silvertop (mod 90) and Bluetop (mod 99) except the plumbing to the cylinder head. Everything else is exactly the same

[kloot piloot]

Ja Duck, what I meant is that silver tops are older machines thus more prone to brittle pipes, membranes, rubbers, plastics etc.

[skybound®]

There are known cases where the silver top just gets tired after running for an hour or so

Also check fuel pump membrane, since you are talking about a "not a blue top 582"

There's no difference between a Silvertop (mod 90) and Bluetop (mod 99) except the plumbing to the cylinder head. Everything else is exactly the same

Also the crank was upgraded on the blue top (or more accurately all 582s after serial 4,172.665) But if you have replaced the crank after July 1994 then it would be the newer crank which could be retrofitted to the silver tops.

[John Young]

There are known cases where the silver top just gets tired after running for an hour or so

There's no difference between a Silvertop (mod 90) and Bluetop (mod 99) except the plumbing to the cylinder head. Everything else is exactly the same

Quack-Mate Howdy,

"Except plumbing to the head" which is why there are known cases of them getting tired - saw one myself.

The retired Dave Miller will be able to tell you a bit more about this. Still plenty of them flying.

Keep well. Regards
John

[Boet]

Check the pulse line between the pump and the crank case for leaks. Is your pump lying horizontal or vertical?

[nickjaxe]

Does it go direct to idle or slowly drop to idle....when you land is the engine still running at idle or has it stopped,

You say once landed I can go to full power ok....is that after stopping the engine first????

Does the throttle feel normal....


Nick.

[Morph]

Revs are controlled by the carbs, fuel and air

if the vent pipe is blocked the fuel will initially be supplied and normal operation will occur, but as the tank vacuum increases the engine will begin to die. Switching on the electrical pump will show a difference, for a while. This happened to Ranger flying over Franshoek one. Turned out the the vent hole was drilled in the top of the cap, and the plastic shaving from the drill was not removed. the air suction thus pulled it into the hole, blocking it. This will take minutes not hours.

But if you are flying and suddenly it goes to idle tells me there is something wrong with the mechanics of the carbs. On both carbs at the same time, points to the throttle cable mixer that splits one into two.

When this happens again keep your throttle open (or open your hand throttle) and land. Take the airfilter off and look at the slides. They should be open. Maybe the single cable is jumping loose after extended usage and once landed and the throttle released it clicks back into place.

The engine is definately running right, not just windmilling. if that is the case then it is electrical.

Opening the choke will make the engine run a little rougher, the revs will drop rather than increase