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PostPosted: Sun May 21, 2006 2:35 am
by JPXman
ok so after installing 40/17 props on both engines, we discovered that one turned at 3650rpm and one turned at 3900 rpm....

suspecting the points and seals that we just replaced, we replaced both on the 2nd engine.

after testing, we discovered that the two props that I have are vastly different!

same engine, testing one prop at a time, we achieved 3650rpm and 3900rpm on the same engine! so what we thought was an engine problem turned out to be a difference in propeller!

So if you're troubleshooting a weak engine compared to the other engine, try swapping the props....


PostPosted: Mon May 22, 2006 12:28 pm
by Chappy
Tyler, I thought you had already tried swapping the props. Are these homemade props or commercial ones? Unfortunately, it's not unusual to find a fairly large difference between props made by different companies, but you shouldn't see that kind of difference between props from the same company! I've made a couple pairs of props for my series 1 with redrive Pioneers, and the worst pair never had more than about 75 rpm difference between them - I'm a wood butcher.

Anyway, I'm glad you solved the mystery!


PostPosted: Wed Jul 05, 2006 3:42 am
by JPXman
they were both from culver, but from different batches i suspect. I just got my hands on a 3rd culver prop of the same advertised dimensions so we'll spin it up and see what we see.

may 20th i had yet another engine quit. It was due to siezure as well. We suspect that my carb tuning gizmo is letting the high speed jet walk itself lean during flight, and that my 40:1 oil ratio is too lean. I will fix both problems, as well as the bent axle and downtube :( this will be a big job to fix, but i hope to have the 2-seater flying in the next couple of weeks so i can at least enjoy the summer flying.

PostPosted: Tue Dec 19, 2006 11:55 pm
by JPXman

I've just now come to the end of the re-re-build of my 2-seater (not the series III) and am ready to fire up the engines. I am curious to see if they'll run right - they did on the stand a few months ago, but its different when you hook up a new fuel tank, filters, fuel pump rebuild, new fuel line, clamps, etc etc...

keep your fingers crossed for me, i'll post a pic of the newly reborn bird next time i'm out. i have to thaw out the pegs that hold the hanger doors closed, they are frozen solid into the ground.....


PostPosted: Thu Dec 21, 2006 11:43 pm
by JPXman
well, she's all tuned up and ready for action now. the engines fired up on about the 7th pull and ran smoothly. i have to say that the EGT guages I installed are MINT when tuning. i was able to tweak the high speed mixture to get about 1125F at max rpm, as apparently 1200F is the red line for 2-smokers. i tuned it the way i normally did, and then tried with the EGT.

my old way, i got 4290rpm and would have been satisfied. after checking the EGT it was only reading 1050F. i tweaked it until it read 1125 and i got an extra 50rpm out of it! i'm confident now that these engines will not quit due to seizure like the other pair on my series III.

the new fuel filler neck i put in is awesome too - no more hunkering under the wing.

next warmish-calmish day i shall take to the air. i haven't flown this beastie since september 2004!


PostPosted: Thu Dec 21, 2006 11:46 pm
by JPXman
one more pic, out of daylight and too windy, but ready to go!

PostPosted: Fri Dec 22, 2006 9:58 am
by uscgairdale
I'm jealous......about the plane, not the cold.


PostPosted: Fri Dec 22, 2006 10:48 am
by russell
I second that. If I should look outside and see all that white I would have to think I'm dead and that old saying " when hell freezes over" must be true!


PostPosted: Fri Dec 22, 2006 3:00 pm
by JPXman
dave you've had to come a lot further than i did with my rebuild - at least there wasn't a tree in my wing ;)

i see the double tank behind the seats, right on man. i can send you some detailed pics if you like that filler neck i did, man was that easy to fill that tank of gas compared to doing the bench press under the wing....

keep at it buddy,


PostPosted: Wed Jan 24, 2007 8:22 pm
by JPXman
well the 2-seater flies again! was about 3 deg C today and the wind picked up, but i got in about a half an hour before i got too chilly and came down. i need skiis man, i haven't flown the winter in a long time, and seeing every field covered in a blanket of snow providing infinite landing strips made me cry that the only place i knew i could land safely was the strip or a road...

so off to the shop on friday to make some skiis.

engines ran perfectly, but when i did the walk around i noticed a bit of ice suspended in the fuel lines. anyone else who flies in winter see this? i ran the engines for a good 10 minutes before going up and the lines had cleared out.