T.R | Title | User | Personal Name | Date | Lines |
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747.1 | | ROBOAT::HEBERT | Captain Bligh | Tue Sep 04 1990 10:41 | 31 |
| Assuming the engines are mechanically in good shape:
-case seals intact
-rings not frozen
-reed valves intact
-new spark plugs with the right gap
-you get a fat BLUE spark
-you have fresh gas with the correct oil mixture
-you are able to pump up the squeeze bulb until it gets quite firm
--- they should start.
I would NEVER, NEVER use ether on an outboard motor, particularly one
that is in questionable condition. The air/gas/oil mixture is sucked in
thrugh the carburetor air intake, passed through the crankcase where it's
used to lubricate everything, then into the combustion chamber. It's not
uncommon for the cylinder explosion to creep back into the crankcase.
Ether is so volatile that the crankcase could explode. Plus, ether tends
to wash the oil off the needle bearings in the crankcase; instant
scoring.
You might run some OMC 2+4 (or is it 2+2?) fuel conditioner through them
But. If they were put away with gas still in the carbs, the guts of the
carbs might be gummed up with residue from evaporated gas. I think that
means a carb rebuild.
Those engines should start within three pulls when cold (first time that
day), and on one pull the rest of the day.
Art
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747.2 | Start with a tune up ... | SITBUL::FYFE | | Tue Sep 04 1990 10:52 | 17 |
|
I would suspect the electrics before I would start on the carb.
Carbs are very simple and rarely fail. You may wish to drain the
carb bowl to remove any sediments that may be present.
Start on the tune up. Make sure you check the ohms reading for each
of the coils be within spec. Replace the two sets of points/condenser
and set to spec. Any boat shop can tell you what the proper gap is.
Also check the plug wires very carefully. A worn or broken plug
wire can be the cause of many performance problems from rough starts
to won't run at all.
The reasons for the performance differences span from the performance
of the motor to improper propeller pitch to lower end depth.
Start with the tune up.
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747.3 | Still wondering about how to change points | COGITO::ZIKA | z | Tue Sep 04 1990 13:41 | 13 |
| .re last 2
From what I understand (1) Never use Ether (2) Rebuild the Carb
(3) change the points and condenser (4) Check the electrics
Any tips on changing the Points? Is a gear puller really necessary?
The gear puller I have is medium sized and meant for a three-six inch
gear. Do you think it will work?
I found a Johnson Dealer across from the Pheasant Lane Mall in Nashua
and will try to get some info from them when thry're open.
Thanks for the info, Chris
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747.4 | Get the service manual for the engine too! | SITBUL::FYFE | | Tue Sep 04 1990 14:38 | 13 |
|
You will need a flywheel puller which uses three screws to attach the
flywheel to the puller. Do not use a standard gear puller as you
can damage the teeth of the flywheel and even warp it.
Second, since the plugs are getting wet with fuel I would put off
rebuilding the carb till after the electrics are dealt with
and tested (tune-up-wires-plugs).
You can get a puller at Sears in the mall or if you live near Milford
I could come over and pull the flywheel for you.
Doug.
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747.5 | MAGNETO PLATE COULD BE WORN ALSO | BIZNIS::CADMUS | | Fri Sep 07 1990 16:45 | 25 |
|
BOth these, motors are a little long in the tooth. a common problem
with these older magneto ignitions is that the magneto plate (the plate
that the coils and points are mounted on) gets worn and sloppy where it
rotates around the engine block- check the palte fro any sloppiness- I
have seen them so bad that hou could open and close thepoints by
wobbling the plate.
If the carbs are adjusted properly, the engine should start up cold
w/choke or hot w/o choke on one or two pulls. I and my son have had 4
of theses basic 35/40 engines o=ver the years- they are tough
,relioable, simple.
Get yourself a meanual- get the carbs adjusted, check
points/plugs/wires/mag coils, and mag plate. Use fresh gaso;ine with
the correct gas/oil ratio and she should start right up.
The ignition sysrtem on all these old 2 cyl OMC enginwes is the same.
Poinmts,condensor,coils are interchangeable. They are also the most
unreliable part of the engine- magneto coils and condensors frequently
fail- also the plugs used to dib=ve me nuts- one drop of water in the
gas and they were history- same if a plug got oil fouled. Other than
t5hat you couldn't kill these engines.
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747.6 | Timing is everything | DECWET::SCHMUHL | | Wed Sep 12 1990 15:38 | 10 |
| The warm starting (hard) sounds more like too advanced timing. One or
two degrees can make the difference between hard starting and fouling
plugs. Start with checking the timing on the one who starts different
when hot. Check also that the advance mechanism isn't binding. BTW,
old Johnsons run best when you open the throttle widest, back off until
just before the revs die down (takes a little practice and feel). This
allows the engine to fully advance the spark without over driving the
carbs (max RPM + min fuel = best performance)
Larry (who owned lots o' Johnsons)
|