Topic: 1948 Evinrude Sportwin 4423 Revisited – Antique Outboard Motor Club,Inc

This topic has 13 replies, 5 voices, and was last updated 9 years, 7 months ago by Buccaneer.

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April 22, 2015 at 11:21 pm #1297
Buccaneer
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Tried again to get my Sportwin running after a refurbish last Fall.
Now that two out of three people say that my pistons are in
the correct way I had a renewed sense of "hope".
Checked the compression (new rings, and a grand total of
about one minute running time) and came up with 75 and 78 psi.
4423 poster "Bob" says his was at 84 and 88.
I put new plugs in it, fiddled to the low speed air shutter adjustment,
and was able to fire it up on the test stand after a few tries.
Let it run for about twenty seconds.
Tried next in the test barrel………. Yep… won’t start, or only
runs a couple of seconds. Put it back on the test stand, and could
not get running again.
Reminds me of my opposed twin Neptune that probably has a loose
upper main bushing.
This Sportwin has an upper bushing, plus a sealed ball bearing,
so I wouldn’t think it "sucking air".
Could my compression be too low for this engine, pistons in backwards
after all, or is it afraid of the water like my Neptune?
Ideas?
Thanks, Bucanneer

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April 23, 2015 at 1:32 am #14542
bob
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HI BUCCANEER…I DOUBT IF IT IS A COMPRESSION PROBLEM SINCE IT IS STARTING UP WHEN NOT IN THE BARREL OF WATER IN A FEW TRIES.I HAD THE SAME PROBLEM AS YOU ON A DIFFERENT MOTOR,A 1980 MERCURY 7.5.NOW KEEP IN MIND,THAT MERCURY HAS AN OBVIOUSLY DIFFERENT IGNITION (ELECTRONIC)THAN WHAT YOU ARE DEALING WITH.AFTER GOING THRU ALL THE USUAL CHECKS AND FIXES ON MY MOTOR ,EVEN HAVING A MERCURY MECHANIC HELP,IT JUST WOULD BARELY FIRE IN A BARREL AND QUIT IMMEDIATELY.CALLED A CAR MECHANIC I KNEW AND HE SUGGESTED EITHER WIDENING OR CLOSING THE GAP OF THE PLUG BY A SMALL AMOUNT.(IF I REMEMBER I WENT FROM .040 TO,045)AMAZINGLY,IT WORKED.HIS LOGIC WAS THAT MANUFACTURES SET THE PLUG GAP BASED ONLY ON COLD STARTING WHEN THE VEHICLE IS NEW.OBVIOUSLY,MOTORS CHANGE WITH WEAR AND AGE.AND I DO REMEMBER READING THAT THE BIGGER THE GAP ON A PLUG THE MORE FUEL AND AIR COMES INTO PLAY WITH THE SPARK,AND VISA VERSA IF YOU SHORTEN THE PLUG GAP.IT IS A LONGSHOT AND MAYBE IT SOUNDS CRAZY,BUT IT MIGHT WORK FOR YOU.MAYBE I JUST GOT LUCKY.I AM SURE THERE ARE A LOT BETTER QUALIFIED PEOPLE ON THIS FORUM WHO CAN HELP YOU…OH,AND THANKS TO YOU,AND GARRY AND OTHERS FOR HELPING ME WITH MY SPORTWIN.REALLY OPENED UP MY EYES.WILL BE WORKING ON IT THIS SUNDAY HOPEFULLY.GOOD LUCK! BOB
April 23, 2015 at 3:16 am #14548
Buccaneer
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Bob, thanks for the idea. Hope it turns out to be something simple like that!

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April 23, 2015 at 8:26 am #14551
legendre
Participant
Since it’s been brought up, here are a couple of comments on plug gap..

First thing to know, is that the plug gap determines – to a certain degree – the voltage of the spark. Think about it – the wider the gap, the greater the voltage required to jump that gap. So, for a given coil / magneto system, a wider plug gap forces the spark voltage to rise high enough to jump the gap.

Secondly, plug gap has a +significant+ influence over a motors’ tendency to be ‘cold blooded’.. wider gaps (if they can be reliably fired!) can and will reduce undesirable warm-up behaviors.

But once the gap becomes too wide, to the point that it can no longer be fired, then reliability truly suffers. Also, there are some cases where the (high) voltages developed by using a too-wide plug gap can injure the ignition coil, points or other components in the system.
April 23, 2015 at 1:04 pm #14564
Buccaneer
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US Member
I gapped the plugs at .030. Suppose I should look for specs and see if
that’s correct, but I do have nice blue spark on both cylinders.

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April 23, 2015 at 11:41 pm #14598
Buccaneer
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US Member
Finn Irgens I hate your Evinrude 4423 Sportwin carburator design,
and I hope Ole is giving you an ear full right now about it!
Now that’s off my chest, I did manage to get the infernal thing
running today, after much "fiddling"…….. but something
aint right!
While running in the slow to fast range, If the air shutter adjustment screw if backed off from full seated
it will bog out and die right away. It appears to flood out, as the only way it will restart
is with the fuel needle / knob turned all the way to "off".
One source says the air shutter screw should be 4 turns open initially,
another says 6 turns.
Some times it will be running good at mid speed, but when you transistion to
"Fast", it will bog out and die, and act flooded.
I can get it to idle better if the air shutter is forced further (open?) against the tension
spring.
Am I understanding correct that "the slower the engine speed selected the further
the air shutter is open? So in the photo in the link, showing the shutter covering
the hole completely on the compensation port, would be with the engine running
full out? …….. shutter closed, full venturi action drawing more fuel for high speed?

http://grayhitandmiss.com/Outboards/442 … taway2.jpg

Anyone know the initial turns open for the fuel mixture needle?
Right now I have the knob centered on 3/4 turn open. It was further,
but seem to run better with less.
Thanks for any ideas, Buccanner

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April 24, 2015 at 4:34 am #14621
garry-in-michigan
Participant
Lifetime Member
I recall them running a two thirds to three quarters of a turn, it depends on how worn the needle valve seat is and how much varnish is in the venturi. I always file back the spark plug electrode to leave a sharp edge and a more open spark. Some motors run better with the gap facing the transfer port. You should not have problems with the top main bearing, its a sturdy ball bearing.

. . . . . . 🙂
April 24, 2015 at 12:26 pm #14634
Buccaneer
Participant
US Member
Thanks Gary. There shouldn’t be any plugage in the carb after
thorough probing and pinesol soaking last Fall.
I can’t remember anything about the venturi. You mentioned it
was a replaceable part. Is it plastic or metal I wonder?
Suppose it could be buggered up.
I’ll try resetting the fuel needle back less from 3/4 turn open,
and fiddle with the shutter some more.
Not sure how much more "pulling" my shoulder will take today though!

P.S.- I can’t remember much about the exhaust silencer inner workings.
I do remember there’s another shutter in there to bottle up the
crankcase. Anyway, the silencer exhaust out the back of the
spring like tube, but it seems to be blowing air, not exhaust.
When I plug the tube hole with my finger, it does affect the engine rpms.
How do it work, and is it working correct? 🙂
Buccaneer

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April 25, 2015 at 4:31 am #14703
garry-in-michigan
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Lifetime Member
It is brass –
April 25, 2015 at 4:36 am #14704
Mumbles
Participant
Are you sure the replaceable needle seat is still in the carb? It may have fallen out causing the over rich condition.
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