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PostPosted: Sat Jan 27, 2007 6:56 am
by xgary
TYler , Whatd kind of oil are was the engine been using prior to the seizures ?

Were they cold seizures ?

PostPosted: Sun Jan 28, 2007 1:32 am
by JPXman
i was using Yamalube at a 40:1 mix.

this time, i'm using penzoil air cooled at 32:1 in the other JPXs i have running on my 2-seater. i figure the richer oil mix will keep them cooler and more lubricated, but i'll keep my eye on the plugs for fouling.


PostPosted: Sun Jan 28, 2007 1:40 am
by xgary
Is the yamalube mineral or synthetic?

also the fuel acts for cooling as well on a 2 stroke and a overly lean condition will not cool as well.

Were the engien fulll warmed up ?

PostPosted: Sun Jan 28, 2007 4:31 am
by JPXman
yep fully warmed up, and the last one was at 200' :(

mineral yamalube, i stay away from synthetics and 2-smokers. haven't heard any good arguments yet about their advantages. i have a feeling there's a dried out gasket on the engine somewhere and is sucking in air leaning out the mixture.

same carbs on the other two JPX's on my 2-seater and they are running strong.


PostPosted: Sun Jan 28, 2007 6:54 am
by xgary
leaking crank seal will give you lean conditions.

you have a egt gauge now ?
If so that will be your first inidcator of pending troubles

PLugs actuallly tell the tale the best and EGT did give you a real time indication of changes in realtime.

Did the plugs indicate and differance from cylinder to cylinder and from engine to engine when it failed ?

PostPosted: Sun Jan 28, 2007 3:04 pm
by JPXman
had just finished changing the crank seals. both plugs were white. suspecting something wrong with those reed valves now, but thats a project for after i rebuild the fuselage with george-made series III gear.


PostPosted: Sun Jan 28, 2007 7:33 pm
by xgary
white plugs normally indicate lean --VERY LEAN .
what did piston look like ?

PostPosted: Mon Jan 29, 2007 2:33 am
by JPXman
yes thats how i knew it was seizure and not fuel starvation. white plugs bad - chocolate brown plugs good.

haven't gotten to that yet, like i said, probably a project for the spring. i'm knee deep in grinding and cutting aluminum to make my skiis. have one almost done, starting the other tomorrow hopefully. i'll have to take a pic of the scenery for the lads down under who've never seen a white landscape.


PostPosted: Sat Feb 24, 2007 6:51 pm
by JPXman
Skiis are done and mostly on the 2-seater now. had to make 5 skiis! two mains, two tail skiis, and a nose ski! (the 2-seater spends a lot of time on its nosewheels taxiing around... just have to fab and attach the safety cables and bungees. all 5 skiis weighed in at 19 pounds total.


PostPosted: Sat Mar 24, 2007 2:14 am
by JPXman
a few pics of my first flight on skiis ever :)