I have an Italian ST 75 that I just love and it got clobbered the
other day. The carb and muffler were basically destroyed but the
crankcase and all the internals escaped miraculously. I know I can't
get Italian parts and I was wondering what I could expect by buying a
new carb and muffler set up and using them on the Italian crankcase.
Are the Chinese parts compatible with the Italian stuff? I hate to
give up this engine as its performed so perfectly for me.
I also have a problem with an Italian ST 45. The carb. has the old
thumb screw on the low idle side. About half of the threads broke off
of the skirt part therefore I don't have enough threads for a proper
setting. How do I resolve this issue? New part, new carb(will it
fit), or what? I tried soldering the skirt back on to no avail.
You are not going to believe this one, but try it and be surprised.
Build up the area with JB Weld. There are two ways to go about it, but both
assume that you are going to prepare the are to be bonded, by cleaning very
well, and acetone would be the best to use after alcohol, with no oil-of
Also, don't use the quick JB Weld, as it is questionable about being fuel
proof, so I have heard.
One way is to build up the area and then drill and tap it. That is probably
the harder way, since you have to be able to drill it accurately before
tapping it. One way to do that is to get it lined up in a drill press vice,
with a drill into the old hole, and then don't move it as you apply the JB
Weld. After it cures for 24 hours (48 is even better) then you can proceed
to drilling and taping it.
Another way is to use Vaseline to lightly coat (put it on, then wipe
practically all off) the screw, and put it into the hole. Then, build up
some JB Weld around the outside of the body, and pay attention to how the
leftover is setting. When it is almost completely hard, work the screw out
carefully, put a little more Vaseline on it, and thread it back in. Wait a
while, and do it again.
I did this to a Fox carb probably 10 years ago, and it is still holding like
a new crankcase holding the carb.
If all else fails, you can JB Weld it in place permanently.
I tried the JB Weld on the outside of the needle skirt and it seems to
have worked. I will have to run it yet to see how it holds up.
If there is a problem with it I would like to know if the new style
(Chinese) lo speed needle will fit into the old style carb. barrell.
Or will it require a new barrel, and if so will it fit into the old
Also, I have a Super Tigre 51 (Italian) that has started spitting grey
matter all over my plane, I assume that means bearings or sometning
needs replacing. Would it be worth the time and expense to go into it
and replace parts or just buy a new ST 51 for $85?
Glad the JB Weld worked. If you got the parts getting bonded good and
clean, and you used enough, it is there for good. I have been flying that
type of repair for well over ten years, I think, and it has never given me a
hint of failing.
Don't know about the specifics, on this.
I would guess that the fuel you are burning has castor oil in it, and the
gray/black goo that comes out is completely normal for fuel with castor oil,
in small percentage of the oil content, or all castor oil.
That is a reason that some people do not like castor oil. The mess is
unfortunate, but castor oil is the best insurance you can buy to protect an
engine from a run that has been over leaned, and to protect an engine from
rust and corrosion while it is sitting between flying sessions.
Fly it until it does not run anymore, or is not reliable. You will probably
not have a problem, but it is hard to tell over the internet! <g>
What Jim said is all true, I might add that a loose screw on the header or a
loose muffler may cause that residue. It could be bearings, or con rod or
cyl & piston, anywhere there is metal on metal. Take it apart and see if
you can tell.(the metal shavings at the con rod to crank bushing on my K&B61
was a pretty good clue) In My Humble Opinion a good engine is worth putting
in Boca bearings(maybe Paul McIntosh has some) but not worth replacing all
Check all screws and engine to engine mount first.
What he said!
I did not figure theis in, partly because I didn't think of it, and partly
because I would have hoped that he would have seen something as obvious as
this, and corrected it to see if the gray gunk stopped.
At least, that's my story, and I'm stickin' to it! <g>
Also, if there is an area that looks like it has been polished from parts
rubbing together, it will be very obvious, and very different in appearence
from the surrounding metal. One area that comes to mind is on the back
plate. Some minor circular polishing is normal, but much more than what
would be caused from an occasional rub could indicate a serious problem,
then for most any case, go for replacing the bearings to solve it.
I used JB Weld several years ago to repair a broken exhaust flange on a
Saito 4 cycle. It worked like a charm and held up extremely well considering
the incredible heat generated right at the exhaust port. Great Stuff
No, Great Stuff is used to fill cracks around window frames, and pipes and
stuff, to prevent house air leaks.
Oh, you meant that JB is good stuff, eh? <g> Sorry, I had to do that!
Yep, I hear one tale after another, each topping the previous one, about
well that JB seems to hold.
Ya know what? I believe them all!
I have only had one failure, and it was a long shot, at best. In other
words, I expected it to fail, for what I was asking it to do.
The only thing that it will fail at, occassionally, is where it is expected
to take a substantial structural load.
Like your exhaust flange? If it has screws holding it, and the JB is to
fill it out and seal it (and perhaps take some of the load), then it will
work every time. It is rated at 500 degrees F, but I swear it will do better
Hey, they even make a permanent radiator sealer product. Also, a two 5
ounce tube industrial size. I gotta get me some of that!
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