TeamMuir1

My Feedback: (-1)

hello everyone... I am new to this site.... I was told about this GREAT PLACE by a friend.....
and it is just that supper support center.. lol...
so HERE is my situation...
I bought a saito 4stroke.. used.... He said it was in great running condition... So.. I have worked on my P-51.. all say yesturday.... lol
just to finaly start it this afternoon.... IT starts... it runs smooth but as soon as you POWER up.. .. it makes a HUGE knocking sound and then DIES...
It will restart immediatly... no problem.... let it idle... then POWER UP...SAME thing happens time after time...
So .. all KINDS od Questions arise????
was the motore ever takin apart...????
was the timing off....????
is the cam WORN?????
for someone that knows oviously more than me..... with making that kinda noise....someone autta have a good educated guess as whats wrong?
NOW>>> I have taken the motor apart..... in hopes to find something BROKEN.... but nothing is......everything is ok... and there are no metal shavings anywere..... PLEASE PLEASE some one give me some insight on this problem..... THANKS>>>GUYS.....

alan0899

G'day Mate,
Check cam timing, valve clearance, & make sure it is not too lean, on the top end needle. Those are my educated guesses!

w8ye

My Feedback: (16)

Open up the high speed needle -- It is too lean on fuel

rcdude7

My Feedback: (264)

If it's a rattle sound, it's detonation, back out the hi-speed needle til it stops, Some engines will react rather violently when they rattle and try to kick the prop off in you face.[:@]

William Robison

My Feedback: (3)

Muir:

I'm in agreement with the lean high speed, but there are other considerations as well.

First, many of the FA-80 engines in use are the "High Compression" version, with these 15% nitro is pushing the upper limit. 5% runs more easily in them, and gives better fuel economy as well.

Next, whether it's "High" or the later "Low" compression version it runs with more power and less wear with the valve clearance set to minimum, you said you checked, but did you set them to 0.0015" clearance? The close setting, along with castor oil in the fuel, will greatly decrease the wear on the acm and lifters as well.

Finally, if none of this helps, there is an upgrade kit for the carb that seems to settla any of the FA-80 engines down.

Bill.

Hobbsy

My Feedback: (102)

I'm glad you got it worked out, always suspect the needle settings first and things like airleaks, cam timing, worn cams, etc last and you won't waste a lot of time shooting in the dark.

scratchonly

If your low speed adjustment is turned in too far, it can prevent your hi speed needle from richening the mixture. Back your low speed out if this is occuring. I needed the upgrade kit to allow me to run the 80 inverted without glow heat. A velocity stack also helped quite a bit.