Trouble shooters?
- Thread starter scottsville
- Start date
scottsville
Registered User
Update: Checked for induction leaks with WD40 running and no sign on the engine sound. Did a static pull test and got barley 2250 rpms. Borer 82-44 stc states min of 2300. But did order all new gaskets and intake hose. Also going to send mags off to get 500 hr check. Also been talking with avstar on the new carb. Hopefully they can give me some input. It feels like it is flooded. Very old diesel pick up feeling power. But the guys that I have talked to that have huge experience are saying it sounds lean to them. I have tested at higher rpm on leaning the mixture to see if I can get a rpm rise. But it does not. if the new induction gaskets and hoses and rebuilt mags do not do the trick. I think we will check on fuel flow and start checking cam lobe wear etc... Motor runs smooth and nice. Just no power!
BC12D-4-85
SPONSOR
Fairbanks, AK.
Maybe asked and answered already but does adding carb heat = richer mixture help or hurt rpm?
Gary
Gary
TurboBeaver
Registered User
Northern Maine
Have you checked the damper in the airbox? If it's sloppy and not fitting tight, so
It won't move back when you push on it??
Doesn't take much to start blending "hot air" into your carb....... That combined with
44" of pitch would do just what your saying it does.[emoji848]
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It won't move back when you push on it??
Doesn't take much to start blending "hot air" into your carb....... That combined with
44" of pitch would do just what your saying it does.[emoji848]
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scottsville
Registered User
I have a friend that has had 7 SC 150's over the years and he always ran 82-44 on them and he said he never had a issue running them up to 2800 rpms straight and level flight. The Borer STC states min rpm out of a 150 is 2300 to 2400. I am barley getting 2250. Don a Sensenich says you should have no issue hitting 2700 rpm in straight and level flight with the 74-56 sen prop. I might be able to hit 2500 on a good day. I have a Buddys SC 160 with a borer 82-42. which is 2 deg flatter than mine. and 10 hp difference. It takes off over twice as fast as mine. I've flown it a bunch. There is a huge huge difference in them. I believe there should be a pretty big difference between them. but not over twice as much?
scottsville
Registered User
I hear ya on taking advantage of the borer. That is the hole idea.
scottsville
Registered User
I have heard that every degree of pitch is about 50 rpms? Is this correct?
I recall my prop guy saying 25, but that's comparing new props that have been tuned. Factory props are a crapshoot. And to compare a new prop to a used one that's been filed or re-profiled is more of a crapshoot. The rule of thumb I was told by one of the best Cub mechanics ever is that we want 2400 minimum rpm at full power static. My preference is not to overspeed in full power level cruise. On my old -12 with a very healthy 160hp an 82-42 was a perfect match. Most of my Cub friends use 82-41, even with 160hp. I do have a friend that had an 82-44 on a 320, but that motor wasn't stock.
cgoldy
Registered User
Moogerah Queensland Australia
I had a VW beatle when I was a kid and it was a dog. My Dad said it was because I had fat tires on it. What would he know! Spent a fortune looking for the reason the engine was not performing. Turned out the old fart was correct.
wireweinie
FOUNDER
Palmer, AK
I always hated when that happened. Now that I'M the old fart, I hope I can keep that trend going.
Web
BC12D-4-85
SPONSOR
Fairbanks, AK.
Loosing the restrictive whistling perforated baffles in the VW's twin muffler outlets opened'er up. But I get the analogy of a too large prop load vs tire load.
Gary
Gary
Charlie Longley
MEMBER
Anchorage, AK
So what’s the thought on Borer prop pitch. I am building a 160. 82-42 or 41?
I run a 43 on my 160 for everyday flying. At 2400 every inch change = 2.5-3 mph change. If you don't have to pull a big load off short the speed of a 44 is nice. If you have a good running engine I would say the takeoff distance change is not that much difference, 30 feet maybe, between a say a 40 and a 43. If your not making good power is would have a much greater affect.
DENNY
DENNY
supercrow
FRIEND
Smith Pond near Millinocket, Me
Don't take this as a message for the sake of argument, but. From what I have experienced: If the fellow who flew several stock 150 0320's was consistently getting them to 2800 with an 82-44 I think he had the nose pointed slightly downhill or used the same tach in all the airplanes. You may have other issues to find, but when you do, you will still be better off with a 41 or if willing to give up a little take off and climb performance then maybe a 42. As others have stated here the 44 is too much prop, generally, for the 150. Just my 2 cents. I hope you are able to find your problem soon.
n40ff
Registered User
WV
I had a HIO360 that wouldn't make power. Bought as a core with plans to rebuild. Seller said it was running good when removed(don't believe it). I decided to hang it and see how the airplane(Acroduster) flew with more ponies. It should have made 2350-2400 static but wouldn't even do 2000. Overheated quickly, oil temp went up as pressure went down...Of coarse I didn't fly it.
I pulled the suction screen and it was completely full of the rod bearings. That's what you get when an engine is just too good of a deal. Rods were scrap, case was cracked and crank was bad. Live and learn.
I pulled the suction screen and it was completely full of the rod bearings. That's what you get when an engine is just too good of a deal. Rods were scrap, case was cracked and crank was bad. Live and learn.
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Depends on your mission. There were times when I wished my “41” was a 40 or 39 on a 160hp. When canyon walls and cedar trees fill up your windscreen I have a tendency to want less pitch.
flynlow
FRIEND
Fowler, Ks
I hear ya but my 150 hp will spin the 41” prop past 2800 at 3000’ msl level WOT
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BC12D-4-85
SPONSOR
Fairbanks, AK.
There's new props and worn props. Props that conform to new spec limits can put more of a load on the engine than well used models. Careless profiling changes the airfoil shape and so on.
Gary
Gary
Pull it back then;-) It’s a compromise. If you’re worried about speed and WOT buy a bonanza!
I get where you’re coming from leaving a little on the table at cruise but I’ll give the top end up for bottom end any day in a cub.
You aren’t far from Amarillo. Bring that under under-propped thing down and we’ll play in the Palo Duro Canyon. You’ll appreciate your fine pitched club. Promise!
Flynlow, here’s my other point.....Fowler, KS is 181nm from my home strip. Given a few KTS headwind, a 75kts cruise on Bushwheels and a 41 pitch prop it’ll take you 2hr +25 to get to my place. If everything is the same but you changed to a 44 pitched prop and estimating a generous cruise of 81 KTS, you’d shave 12 min off your trip but now that cool 250’ spot in the canyon that you landed easy looks real short when taking off......
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RaisedByWolves
FRIEND
Tx
That’s a funny looking borer
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Getting back to scottsville’s question, I just read through the whole thread and saw two guys raise cam timing but scottsville didn’t comment on those. When the carb is good, the compression is good, the spark is good, the exhaust is good and no inlet leaks - and an engine still will not perform IMHO that points to the cam and maybe lifters - corrosion and wear - or mistimed. Be good to know what it is in the end. I run a slightly cropped 81 x 43 Borer on a 160 which seems about perfect
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