THEAirplanegirl
Registered User
Michigan
Hello!
My name is Thea and I recently purchased an Experimental PA-18-150 Replica. I am having a couple of issues and hoping to receive some insight on this type of motor and any quirks that people might know of! I do have quite a bit of time in Super Cubs (1200+ hours) as I am a banner tow pilot, but most of my time is in 180 HP 0-360s...
A little back story.. This cub was built in 1985 and only has a TT of 595 hrs. The previous owner had it for about 20 years and only put about 200-250 hours on it. Logs are complete and from them I can see that the motor was completely overhauled in 2009 due to a prop strike. At that time a new crank and cam were installed. All new chromed cylinders were installed. Since OH the engine only had about 100 hours put on it and then sat from 2016/2017 until the day I brought it home (8/2023).... luckily it was a short 15 minute hop.
Since getting it back to the shop. We have pretty much gone through everything we can before pulling jugs or doing anything more aggressive. We replaced all the oil lines. I sent out the carb and mags to get them overhauled - even though they had less than 100 hours on them. I installed a new Kellys Aero harness and replaced all the spark plugs.
Post upgrades, I have put about 12 hours on it. One issue I am having is the oil temps are progressively getting higher and are now in the 220 range. I do have a very old oil cooler and put in an order today to upgrade to a new Aero Classics one. I also discovered with this old case I do not have a vernatherm. That is also the next project to replace the current oil screen housing with an updated version that contains a vernatherm. I am also looking into changing out the screen to a filter via airwolf STC.. If anyone has any insight on that I'd love to hear it!
I guess my question is if there is anything else I should be looking at? or really any/all info people might have on this type of motor. Eventually I am installing a Dynon HDX system with full EIS... But for now all I have is oil temp & oil pressure. I do not know what my CHTs are running.
The second issue I am having is the engine seems to be running rough at the 2100 RPM range... This "roughness" was semi the reason I sent out the mags/carb and purchased a new harness. But even after those upgrades it seemed to improve some but definitely is still there. On take off with full mixture it runs great but soon as I start pulling the throttle back and hit the "2100-2150 RPM" range it runs rough. I only make about 2300 RPM on take off because I have a very coarse prop (already ordered the composite Sensenich ground adjustable prop - just waiting on delivery). I have determined this "roughness" improves drastically with leaning but I am having a hard time determining if it improves because the fuel/air mixture ratio is better or with the slight RPM rise from leaning it takes it out of that "roughness range." I am leaning towards it being a air/fuel mixture ratio problem but it seems a little strange to me that its only apparent at that certain RPM. I do have the square carburetor airbox and have heard that these have issues with not getting enough air... again if anyone has any insight on the truth/validity of that statement I'd love to hear it. I am open to upgrading to the dome style airbox if that is the case!
Anyway, sorry for the long winded post and thank you to anyone who takes the time to read it and offer suggestions!
Thea
My name is Thea and I recently purchased an Experimental PA-18-150 Replica. I am having a couple of issues and hoping to receive some insight on this type of motor and any quirks that people might know of! I do have quite a bit of time in Super Cubs (1200+ hours) as I am a banner tow pilot, but most of my time is in 180 HP 0-360s...
A little back story.. This cub was built in 1985 and only has a TT of 595 hrs. The previous owner had it for about 20 years and only put about 200-250 hours on it. Logs are complete and from them I can see that the motor was completely overhauled in 2009 due to a prop strike. At that time a new crank and cam were installed. All new chromed cylinders were installed. Since OH the engine only had about 100 hours put on it and then sat from 2016/2017 until the day I brought it home (8/2023).... luckily it was a short 15 minute hop.
Since getting it back to the shop. We have pretty much gone through everything we can before pulling jugs or doing anything more aggressive. We replaced all the oil lines. I sent out the carb and mags to get them overhauled - even though they had less than 100 hours on them. I installed a new Kellys Aero harness and replaced all the spark plugs.
Post upgrades, I have put about 12 hours on it. One issue I am having is the oil temps are progressively getting higher and are now in the 220 range. I do have a very old oil cooler and put in an order today to upgrade to a new Aero Classics one. I also discovered with this old case I do not have a vernatherm. That is also the next project to replace the current oil screen housing with an updated version that contains a vernatherm. I am also looking into changing out the screen to a filter via airwolf STC.. If anyone has any insight on that I'd love to hear it!
I guess my question is if there is anything else I should be looking at? or really any/all info people might have on this type of motor. Eventually I am installing a Dynon HDX system with full EIS... But for now all I have is oil temp & oil pressure. I do not know what my CHTs are running.
The second issue I am having is the engine seems to be running rough at the 2100 RPM range... This "roughness" was semi the reason I sent out the mags/carb and purchased a new harness. But even after those upgrades it seemed to improve some but definitely is still there. On take off with full mixture it runs great but soon as I start pulling the throttle back and hit the "2100-2150 RPM" range it runs rough. I only make about 2300 RPM on take off because I have a very coarse prop (already ordered the composite Sensenich ground adjustable prop - just waiting on delivery). I have determined this "roughness" improves drastically with leaning but I am having a hard time determining if it improves because the fuel/air mixture ratio is better or with the slight RPM rise from leaning it takes it out of that "roughness range." I am leaning towards it being a air/fuel mixture ratio problem but it seems a little strange to me that its only apparent at that certain RPM. I do have the square carburetor airbox and have heard that these have issues with not getting enough air... again if anyone has any insight on the truth/validity of that statement I'd love to hear it. I am open to upgrading to the dome style airbox if that is the case!
Anyway, sorry for the long winded post and thank you to anyone who takes the time to read it and offer suggestions!
Thea
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