ASSEMBLING A MODEL 72 TWIN CYLINDER MAYTAG

By Staff

1095 Woodmoor Drive, Monument, Colorado 80132

I have enjoyed Gas Engine Magazine for several years. I was born
and raised on a central Illinois farm, so I have many memories of
Old Iron. My lack of space here at home limits the size of iron I
can work on. Our recreation room has been converted into the
‘Tired Iron Room.’

I play with Maytags. They are not big, beautiful, or rare. They
stink a little and smoke alot, but I like them and think they are
almost pretty. They are a nice first engine.

A friend of mine, Glen Mallet, had two Maytags in his shed and
told me that if I fixed one for him, I could have the other. How
could anyone refuse? I picked out the one I wanted and got it
running. I called him and told him I had mine running and would fix
his next. A month or so later, his was running. He came over,
looked at them, said that they looked and sounded good. Since I had
so much fun working on them, he gave them both to me. Thanks,
Glen!

Next, I bought a pick-up load of junkers from another friend. I
went through these and sorted out the ones that could be made
whole. The rest were torn down for parts. Everything was
sandblasted and painted.

When reassembling the engines, I found I would have one part on
and have to take it off to get the next part on. After partially
assembling one engine three or four times, I figured out that a
sequential procedure was needed. I thought about making a little
manual to sell through GEM’s ads (everyone can use a little
extra cash), but since I was given my first two Maytags, I thought
I would pass on the gift of friendship. Here you will find a manual
I made up. I hope it will help some of us part-time old iron
nuts.

Assuming you probably tore down your Maytag, cleaned, and
painted everything, you now find out you forgot how it goes back
together. Follow this manual and things will go together in the
right order.

1. Crankcase and crankshaft

A. Remove seal from crankcase #S-298. Do not distort, tap out
carefully. Behind the seal, between the crankcase and the bushing,
is an oil drain hole that runs from the outer end of the bearing
into the crankcase to the fuel jet intake opening. This must be
free and clear. Drill out with a #50 drill bit; blow out any
debris.

B. Non-taper end of crankshaft goes into the crankcase;
reinstall seal. Now remove crankshaft to make sure oil drain hole
is clear.

C. Check spiral oil groove on ends of crankshaft; it must be
clean and smooth.

D. Check seal on assembly #3967–it must be clean, remove if
necessary. Make sure correct shim gasket between crankcase and
assembly #3967 is in place. Either #14446, .006 – .009 or #14445,
.003 – .005. With crankshaft in place, slide assembly #3967 over
taper end of crankshaft. Tighten to 60 – 80 ft. lbs.

E. Crankshaft should spin freely with no end play or up to .002;
if too tight, increase shim gasket on assembly #3967.

2. Pistons

A. Take piston with rod and rings in place and insert in
crankcase with large slope on piston toward the bottom side of
crankcase. Insert cap through #2 piston hole on the other side of
the crankcase. Be sure to match the marks on rod and cap. Tighten
machine screws on cap. Shaft should turn freely. If play is felt,
file cap until snug fit is obtained then ream with 7/8 reamer.

B. Apply grease on cap #2 and on journal. Cap will go in aside
of rod #1 on#l side of crankcase. Take finger and place cap on
journal and hold in place. With other hand, take piston #2 and
insert through #2 opening of case. You can now hold #2 piston tight
to journal. Carefully rotate case so rod is on top. Remove fingers
and tighten screws. Check play as with #1.

3. Cylinders

A. Inspect rings on pistons, they should be free with no carbon
build-up in grooves. Apply light oil to piston and rings.

B. Make sure end gaps on double top rings are separated. Looking
at end of piston, gaps should be at 4 & 8 o’clock; this
will let gaps miss inlet and exhaust ports. Set bottom ring gap at
2 or 10 o’clock to miss intake port.

C. With rings in proper place, slide cylinder over piston. Make
sure cylinder gasket is in place and turned so it does not block
intake passage. Cylinder will slide over piston. You will need to
help rings compress with screwdriver. Be careful not to rotate
rings. If bottom bolts on cylinder were removed, they need to be
started in cylinder before it is in place against the crankcase.
Tighten bolts opposite each corner. Repeat with cylinder #2.

D. Check that crankshaft still turns freely. It is does not,
reverse process one step at a time until shaft turns freely. This
will pinpoint the problem.

4. Exhaust Connection

A. Turn crankcase and cylinders with bottom side up. Tapered end
of crankshaft should be on your left. Take exhaust pipe S304 and
place it on cylinders with end exhaust flange away from you.

B. Gas tank top will not fit if flange is toward you. With
exhaust gaskets in place, use four slotted machine screws and
tighten.

5. Feed Tube Assembly

A. Hold feed tube assembly #3715 upright with jet tube #14437 on
top, strainer on bottom. You should be able to suck air but not
able to blow back.

B. Jet can be cleaned with a #72 drill bit. Remove screen from
bottom and clean disk check valve. Reassemble and check again.

C. Install with bottom of jet flush with bottom of crankcase.
Turn so set screw does not get in slot.

6. Gas Tank Top

A. Install gaskets between crankcase and #S305 gas tank top.
Turn crankcase over. Seal both sides of gasket with fuel resistant
sealant. Place tank top over feed tube assembly #3715; make sure
holes line up so jet could be removed without removing crankcase.
Torque bolts tight.

7. Magneto and Mounting Plate

A. Make sure all parts are clean and dry.

B. Check all wires for cracks in insulation and for tight
connections. Plug wires should be soldered.

C. Clean all three air gap points on coil; clean with sand
paper-they must be free of dirt and rust.

D. Check points for alignment and pits on face; file if
necessary.

E. Install breaker cam #14523 over taper end of crankshaft.
Arrow should be away from engine, pointing clockwise. Breaker cam
should go on without force. Polish inside of cam and outside of
crankshaft with #320 grit or finer emery cloth.

F. Thrust washer #14522 goes on the outside of cam. It has
keyway that needs to line up with cam.

G. Lay both cam and washer aside and make sure key #14524 will
go in crankshaft, long point up and toward crankcase. Check key in
cam. It should fit without force. Reinstall cam and washer as above
and put in key.

H. Install mounting plate over crankshaft. If it is tight, apply
light grease on crankcase. Make sure screw is loose on back side of
plate. You might need to insert screwdriver in slot on plate and
very gently spread as you start plate on crankcase. As it starts,
make sure cam follower on points does not catch on cam. Make sure
before you push plate all the way so that groove on back side of
plate is toward bottom and fits in tongue on top of gas tank. This
is a must as it sets the timing. Tighten screw on back of plate.
Apply a little grease on cam follower.

I. Points should be set now. Turn crankshaft until follower is
on high point of cam. Set points to .020.

8. Flywheel

A. Put some anti-seize compound on crankshaft. Make sure magnet
mounting plates at open end of magnets are free of rust and grease.
Slide flywheel on crankshaft; line up keyway; push on until
snug.

B. Install V belt pulley next, making sure flat spot on flywheel
lines up with flat spot on pulley. Put on lockwasher and nut;
tighten to 50 ft. lbs.

9. Starter

A. Install stud pin #14454 (starter pedal shaft) in top of gas
tank. This should rotate freely. Install snap ring on end of stud
pin next to cylinder.

10. Air Tube

A. Install air tube connection #14438 into crankcase and tighten
alien set screw. Check alien set screw on feed tube; they are
almost impossible to adjust after starter is in place.

11. Starter

A. Place starter ratchet #S307 on crankshaft. Hole in crankshaft
and starter ratchet are tapered; so is pin #12803. Turn crankshaft
so larger side of hole is up. Check ratchet for largest of both
holes. Put small end of pin in large hole, pin will go almost all
the way through it, if holes are lined up right. Tap pin tight,
rotate crankshaft and spread pin slightly.

B. Lay engine on side with flywheel down. Apply light oil on
each of four balls. Place one ball in each slot on outer edge of
ratchet. Install ratchet pinion #5310. This should be greased and
turn freely. Secure with large snap ring.

C. Install #S317 starter gear on stub shaft. Connect spring
between starter gear and ratchet guard. Remove long bolt from gas
tank lid. Slide guard on stub shaft; reinstall long bolt in gas
tank lid. Push stud shaft tight against snap ring; push guard
against starter pedal and tighten set screw.

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