Reminds me of a story I heard about a fish scale, lodged in a fitting, just upstream from a fuel control unit. It apparently would move between feather and partial blockage. A trouble shooting nightmare.
180 fuel flow issues
- Thread starter Sturgill
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aktango58
FRIEND
9aa9
Might also put your hand on the mags and wire harness and see if things are loose. It could be fuel, but the bounce causing you issues really speaks to an electric (grounding out) issue, or if actually fuel you have something VERY loose moving around like the butterfly in the carb or the carb air box blocking the air
BC12D-4-85
SPONSOR
Fairbanks, AK.
Always good to check muffler for loose baffles. Same for mag switches that have heavy keys hanging.
Gary
Gary
I agree on the bounce being much more likely causing an electric issue...my neighbor had a rotary mag switch that did stuff like that...the weight of the keys bouncing, was apparently enough to excite it.
I prefer a pair of toggle switches these days to rotary switch...never had a hassle with one of them.
Steve.
aktango58
FRIEND
9aa9
Question: "faltering problems"... does it miss? Go silent for a second? Choking trying to run but just won't catch?
Exactly how does the engine sound when you hit the bump? Is it instant, or slightly after the bump?
How long does the falter last?
What happens to the EGT? before and after?
Have you tried to wiggle the wires on the back of the mag switch while engine is running to see if things change? (sometimes having someone else work throttle/brakes while your head is down is a great idea, pull a seat so you can lay down and be under the panel for comfort)
Just tome thoughts to narrow down what might be happening.
What do you mean to check muffler? It could do this?
On the straight runway it goes smooth with any faltering even straight grass runway is good.
Ones it goes on full throttle, and you hit the bump it slightly falter for 0,1s and then it goes back to full rpm when it goes off the runway (to the air) it also goes back on full power without any faltering.
It is on bouncing frequency - sometimes only ones, rarely twice (twice bounce).
Thanks for ideas.
BC12D-4-85
SPONSOR
Fairbanks, AK.
Mufflers have internal baffles....cones or whatever shape with holes through which exhaust gas flows and is redirected. They lower the noise, but if the baffles are loose they can move out of position and restrict the flow of exhaust gas. The main restriction can occur at the muffler's outlet. Blocked flow = excessive back pressure = reduced power.
Typically they can be examined visually first through the outlet, then by removing the muffler and the baffles observed to not be warped or loose in the housing. Tap the muffler both on then off the engine and listen for movement/rattling of loose parts.
Gary
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skywagon8a
MEMBER
SE Mass MA6
If you hadn't mentioned replacing the carburetor recently, I would have suggested a small amount of water in the carburetor bowl. That is still possible, if there had been some water elsewhere in the system which migrated to the carburetor. There is a drain plug at the lower rear of the carburetor. Remove this plug and allow a good solid stream of fuel to flow out. This will clean out the bowl and sometimes eliminates the type of issue you described.
Carbureror is completely new, no water inside :-(
Kid Durango
FRIEND
Rangely, Co
I don’t know if this will apply - but I had a vehicle that would do this on ROUGH roads. It was an incorrectly set float. It had ‘almost’ too much fuel that would slosh about and cause trouble with the jostling. Hoping you get it figured out.
A freshly overhauled and re-jetted carb was the culprit of my fuel flow issues in a freshly overhauled 0470-50 engine. If you have another carb you can trade out with for a couple test flights that could check that possibility off the list. My symptoms weren't the same as yours, but I was experiencing pulsed power on take off, regardless of runway surface conditions. We went top to bottom through the fuel system, never thinking it could be the "brand new" carb.
Dear guys,
let me come back to this issue after a few checks.
I have finally decided to dismantle the fuel flow gauge/switch and did not find anything bad. So we went from the top down and the fuel flow seems to be good (90-100l/h static flow).
Then I went to check exhausts and what was surprising to me is there are two different ones. Left is 320-1 without any baffle, and right is 320-2 with a lot of baffles (you can't see through). Is it ok?
Next step would be probably a magneto coil.
What do you think??
let me come back to this issue after a few checks.
I have finally decided to dismantle the fuel flow gauge/switch and did not find anything bad. So we went from the top down and the fuel flow seems to be good (90-100l/h static flow).
Then I went to check exhausts and what was surprising to me is there are two different ones. Left is 320-1 without any baffle, and right is 320-2 with a lot of baffles (you can't see through). Is it ok?
Next step would be probably a magneto coil.
What do you think??
You're reading the number off the muffler shrouds. Both left and right shrouds are different due to differing locations for scatt tube attachment. What is interesting is the parts book does indicate differing part numbers for the left and right mufflers. I don't think I've ever seen what I could validate were original exhaust cans on an early 180. I always thought they were the same. Not sure what the difference was originally. Is your baffled can the left one that feeds your carb heat? Ensure the baffles in the one can are intact and not rolling around loose. Also see if you can see any remnant of baffling attachment in the other can. I have seen several early 180 exhaust cans where the baffling has burnt/fallen out but are still flying.
Ok - numbers are correct.
What is strange is that left (pilot side) can (the one which is for carburetor) is just the hole you can see through without any baffles, but on the other side there are a lot of baffles so you can not see the light on the other side.
There is definitely nothing loose or moving.
I replaced my original early exhaust with a modified to fit the 180, tunned Cessna 206 Leading Edge Exhaust, prior to their FAA approval for their early 180 exhaust. The early exhaust was restricting the breathing of the Pponk engine. Dane (the original owner of Leading Edge) offered me exhaust cans with what I would describe as "minimal" baffling and a standard cone type. I had him make both. It was all field approved although the minimally baffled can could not produce enough temperature rise to meet CAR 3 requirement for carb heat. Not a problem anymore due to the install of fuel injection. You may want to ensure your left can is producing enough heat.
Anyone out there know what the differences were in the two exhaust cans on the early 180"s? Looks like AWI offers only one muffler part number for their dual exhaust system.
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hotrod180
FRIEND
Port Townsend, WA
I replaced both mufflers on my 53 180 about 9 years ago.
AWI invoice calls them both p/n 0750290-3, as does my early IPC.
The muffler shrouds are different though--
p/n 0750290-19 for the LH, and -20 for the RH.
You are correct. I misread my parts manual. Michael W's mufflers are obviously not matched as they should be. I doubt that's what's causing his problem. Just something else to fix as he continues to trouble shoot his anomaly.
Multiple landings multiple faltering, but sometimes nothing...
Maybe do a timed fuel drain. Time how long it takes to drain one gallon of fuel through the fuel strainer. See if there is any time difference in full fuel and low fuel. Block your fuel vent to see if this effects the time. You are trying to insure you have adequate fuel venting. Directly after you fly the plane are your fuel tanks slightly pressurized?
