Problems You Don’t Read About in the Instruction Manuals

By Staff

464 S 5th Sebewaing, Michigan 48759.

I bought a 4 HP Cushman Cub engine, a few years ago, that
refused to start and keep running. I checked it over and decided it
was because gas was not getting to the carburetor. The gas line and
check valve were all chewed up from someone’s using pliers on
the nuts, instead of a wrench. I cleaned the tank out and installed
a new check valve, one of those made from a brass 1/4 inch fitting,
put on a new gas line. So now I am ready to start, or at least so I
thought!

Now it’s a week later, and I still can’t get it started.
I took the check valve off again and checked the pressure of the
spring against the ball, and it seemed way too strong. So I removed
the spring and put it back together again, and tried to start the
old Cushman. Well, now I could get it to fire one or two
explosions, then it would stop again. I hooked it up to a vacuum
pump. Sure enough, nothing going through the check valve. When the
engine was in the vacuum cycle, the ball in the valve was reverse
checking up against the top of the check valve. I took the check
apart again, took the ball out, and laid the check valve on the
vice upside down, and ground a small screw driver narrow enough to
go inside of the check valve and put it against the top of the
valve where the ball was seating when it was reverse checking. I
hit the screw driver hard enough to put a slot in top of the check
valve, and turned the screw driver 45 degrees and hit it again. Now
I had four nice slots where the gas could go through when the ball
reverse checked. I put the check valve back together again with
just the ball in it and put it back on the engine.

These Cushmans don’t need only about 1/4 turn on the needle
valve to start. I turned the engine over once with my hand on the
carburetor to choke it, and on the second turn the old Cushman Cub
fired up and ran like a 21-jewel Elgin watch. Live and learn!!

I had a friend stop by one day awhile ago with a small Ideal air
cooled engine off of a lawn mower. He said he worked on it for some
time, but could not get it started and he wanted me to look at it.
I told him to leave it and I would look at it when I had some time.
A couple of days later, I took a look at it. It was a late model R
with the gas tank built into the base of the engine. The first
thing I found wrong was the exhaust lever latch out lever had been
welded up, and there was no adjusting screw to set the timing
between the governor cam weight and the latch out lever. I repaired
that, and put a stud bolt in the top half so I could adjust the
timing of the valve lever with the cam on the governor weight.

On this type of governor weight on the Ideal, (and also on the
Novo engines, and there may be other engines that use this also),
if the engine has done a lot of work over the years, the outside
stop on the governor weight gets worn and lets the governor weight
have too much travel. If the engine should backfire, the high side
of the governor cam will catch the stud bolt on the latch and lever
and break it off. That is what happened to this engine.

The next thing I looked at was the carburetor. It was not
getting one drop of gas. I took the gas line off the carburetor.
Everything seemed in order, so I started to put it back together
again. As I was connecting the gas line to the carburetor, I
decided to take the fitting off between the gas line and the
carburetor. It was not just a fitting, it was one of those brass
check valve fittings, and it was installed backwards. No way could
you get gas to the carburetor hooked up this way. I took the ball
and spring out of the check valve, as Ideal engines with a
Lunkenheimer carburetor don’t need a check valve on the gas
line-the spring loaded air valve in the Lunkenheimer carburetor
acts as a check valve. I put the gas line back together, put some
gas in the tank, opened the needle 1/2 turn, and three turns on the
flywheels and the engine started up and ran like it should. I
stopped it a half dozen times and every time on the third turn of
the flywheels it started up. Again I say, one is never too old to
learn, and they don’t tell you these things in the instruction
manuals.

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