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Engine died on landing rollout

lndwarrior

Well Known Member
Engine is an O-235- C1 with an MA3A carb., without the primer pump.

Flown almost 600 hours and never happened before, and now its happened twice in two flights. Not flying it until I can figure this out.

I just finished a very comprehensive condition inspection.

I did replace the fuel filters.

I did not check the fuel pressure afterwards because I didn't think of it at the time.

100 hours on new mags.

Checked timing on condition inspection and it was spot on.

No change to approach and landing procedure. Carb heat full, mixture just slightly leaned. Same as I have been doing for 600 hours.

In both cases the engine died when I pulled the throttle to idle as I was rolling out. In both cases it started right up afterwards.

I would appreciate any and all troubleshooting ideas.

Thx!
 
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Have you checked for proper idle cut off adjustment? Sometimes that needle screw can back off.
Have you (after doing the idle cut off setting) adjusted for a resonable idle speed? That adjustment screw can back off too...
 
what is the idle speed at full operating temp? The fact that ti does 700 RPM before take off doesn't mean it will still be that speed after heat soaking. If the speed is above 700 at full operating temp, next likely scenario is poor idle mixture adjustment. A lot of folks out there with less than optimal mixture settings, then will see issues at the low or high end of the temp range. Mixture requirements vary with air temp and therefore best to find te optimum mixture with ambients in the middle of the temp range you fly in. A mixture that runs really well at 10* is likely too rich for 100* when you account for the heat soak seen just after touch down.

Larry
 
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Based on the maintenance you listed, I’d first check for a fuel system leak - as in air getting into the fuel line.

Happened to me on a Franklin engine, the mechanical fuel pump seals started to let air in. I had to keep the boost pump on after landing or the engine would die. Rebuild fuel pump and all is well.

Carl
 
Engine cutoff during rollout

Initially I was going to say mags. I had an O-320 that would cutoff during the rollout and then wouldn’t start until after it cooled down. It ended up being the mags but your mags only have 100 hrs.

To check your mixture adjustment, when idling slowly pull your mixture out and see if the rpm increases by 50 or so rpm.
 
How are the spark plugs? The O-235 can get pretty dirty plugs. Also check that you get a 50 rpm rise on mixture cutout.
 
Idle

No one has mentioned prop. A wood or wood composite prop requires a higher idle speed to keep in running. A metal fixed pitch or metal blade constant speed will idle at a significantly lower r/m. Wood prop might require 650/700 r/m for idle.
Another possibility is fuel getting hot. Do you have a gascolator forward of the firewall? Eliminate the gascolator and use an inline filter.
 
No one has mentioned prop. A wood or wood composite prop requires a higher idle speed to keep in running. A metal fixed pitch or metal blade constant speed will idle at a significantly lower r/m. Wood prop might require 650/700 r/m for idle.
Another possibility is fuel getting hot. Do you have a gascolator forward of the firewall? Eliminate the gascolator and use an inline filter.

I've been flying with the same prop for all 600 hours. Never a problem before.

Gascolator is behind the firewall and all fuel lines are insulated. All has been the same since built.
 
Initially I was going to say mags. I had an O-320 that would cutoff during the rollout and then wouldn’t start until after it cooled down. It ended up being the mags but your mags only have 100 hrs.

To check your mixture adjustment, when idling slowly pull your mixture out and see if the rpm increases by 50 or so rpm.
I will try this. This is not something I've checked before.

Thx
 
Another wild guess might be to check that the tank vents are clear. At least here it's mud dauber season...
 
I had a similar issue with my O 320 on roll out. The engine ran fine otherwise. The problem was due to float bowl flooding. Trouble shooting involved leaning the mixture when the engine stumbled which would bring it back to life. The flooding was caused by a faulty needle valve seat (not the needle valve).

The actual fuel level in the carb bowl can be checked by removing the carb bowl drain plug and making a temporary replacement plug such as a barbed fitting with a clear plastic tube attached and route it vertically to above the carb. Directly observe the fuel level which should be somewhere below the level of the main gasket. (reinstall the plug before flight!!)

Fin 9A
 
Sniffle Valve

I have had two of these stick, which means they let air into the system. At high vacuum you go very lean.
 
Carb

There is another issue that causes flooding that I have not heard about for a while. The floats on some carbs due to wear will rub against the float chamber and stick enough to cause the carb to flood. I think there is a Marvel service bulletin on this and how to fix it. The Marvel carbs are pretty crude.
 
Problems solved

This is the second time in recent history when what seemed like a single problem was actually two.

Or another way of saying it - the obvious problem wasn't the real problem.

It's a good lesson.

Pulled the plane out of the hangar and took a close look at the carb. There was an obvious leak at one of the fittings on the inlet. "That must be my problem!", I thought.

Spent two hours uninstalling and reinstalling stuff to get at the carb and fix the leak.

Restarted the engine - and had the original problem of wanting to die at idle (700 rpm). Arghhh!!!

Checked the carb manual and the next obvious thing was to adjust the idle needle. Turned out a slight adjustment on that fixed the problem. Ok, to be fair, the "slight adjustment" took me an hour of adjusting, restarting, adjusting restarting, in an out of the plane, over and ever again.

Ended up with a smooth idle after a very long day.
 
...Pulled the plane out of the hangar and took a close look at the carb. There was an obvious leak at one of the fittings on the inlet. "That must be my problem!", I thought.

Spent two hours uninstalling and reinstalling stuff to get at the carb and fix the leak.

Restarted the engine - and had the original problem of wanting to die at idle (700 rpm). Arghhh!!!...
At the risk of stating the obvious, it appears it's a very good thing your relatively benign roll-out stall issue drew you under the cowl to discover a fuel leak before something much worse transpired; eg. fire.

Glad you got it sorted.
 
At the risk of stating the obvious, it appears it's a very good thing your relatively benign roll-out stall issue drew you under the cowl to discover a fuel leak before something much worse transpired; eg. fire.

Glad you got it sorted.

You're right. My "benign" roll out issue could have turned out very bad if the engine quit on short final and I was a bit low. My airport is unforgiving of coming up short.
 
You're right. My "benign" roll out issue could have turned out very bad if the engine quit on short final and I was a bit low. My airport is unforgiving of coming up short.
I think you miss understood my intent. I didn't mean to imply any engine issue is something to be taken lightly.

I mearly meant the fact that you found a fuel leak when you might not otherwise have had reason to be under the cowl was somewhat serendipitous.

Glad you're safe and your problem(s) have been corrected. I'll go back to my corner now.
 
I think you miss understood my intent. I didn't mean to imply any engine issue is something to be taken lightly.

I mearly meant the fact that you found a fuel leak when you might not otherwise have had reason to be under the cowl was somewhat serendipitous.

Glad you're safe and your problem(s) have been corrected. I'll go back to my corner now.
I was not trying to be sarcastic but I can see how it looked that way. Sorry if it came across that way!
 
Did you get your idle mixture set so that you get a 50rpm rise at ICO? Sometimes you have to go back and forth with mixture and idle speed..
 
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