1973 4hp Evinrude

[Crosbyman]

these 4hp do run hot ....so what is HOT ??

the exhaust cover is NOT water cooled like bigger HP models and they frequently become discolored.

measure the engine PH with a IR heat gun to detect any true HOT spots

 

[film495]

cleaned it up and put it back together again. was more judicious with the sealant, so it didn't squeeze gobs everywhere. we'll see. the IR gun is a good idea if it starts pumping water, think I have one somewhere. when I put the lower unit back in, I'll give it a go again.

yea, I dunno what hot is. I run a 3hp Evinrude from 1968 all summer, and my check is to put my hand on the cover after running for a while, and it gets rather warm, but not hot. Probably not a good check, I should spin it and look for water spritzes, but I never do. Lucky.

 

[Crosbyman]

well there you go IR heat gun will tell you how and where it is hot assuming you do pump water. this post 43 on a least complex of OB's ...

good luck.

 

[film495]

seems to pump water fine. let it run for a good while

poor idle and hard starting. seems to run strong enough once started, but I tried another carb on it and it was similar, maybe a bit better, but similar. neither carbs low speed adjustment seemed to do very much and I could close the needle and it had almost no affect on running. so, my guess both of them have gummed up low speed jets/needles.

ordered a kit, we'll see what that does when the time comes.

 

[racerone]

The " hard starting " is usually a weak spark condition.

 

[Crosbyman]

did you inspect and refurbush all telectrical on this 4hp ... simple job

change coils if cracked or black spotted by arcing, condensers, plug wires 7mm solid strand copper wires and boots plugs etc...
adjust timing & sync the trottle cam plate follower

 

[film495]

did you inspect and refurbush all telectrical on this 4hp ... simple job

change coils if cracked or black spotted by arcing, condensers, plug wires 7mm solid strand copper wires and boots plugs etc...
adjust timing & sync the trottle cam plate follower

well, kind of - but not into all the details. I'm not sure how to check/ajust the timing. I check the electrical, point gap, connections, looked it over, I did file and clean the points a little, just as a touch up since I was in there. Looked good to me, make a bright blue spark on each plug, and I'm still running the older test plugs, have new ones, but I'll keep using the old ones to test for now and once running good, put new ones in it. The plug wires do need to go, one was melted a bit from the engine overheating, but it makes a nice spark, I just wrapped it with electrical tape for now.

I did get a service manual, but I'm not sure how to check the timing. I think there are some marks on the flywheel, but I haven't really tried to eye it up yet. I've static timed other points motors, so - same concepts should apply, just need to find the marks.

I don't know how to do the throttle plate cam follower either. Somewhere I recall skimming over directions for how to do it, but also - couple new things to learn for sure.

 

[Crosbyman]

the cam's index mark under the FW must be just touching the carb's throttle cam follower bar or roller at the START position

this leaves the throttle plate mostly closed allowing fuel-air to be extracted from the carb's top " low speed" fuel chamber .

the choke can provide extra suction on the LS circuit to start the engine if hesitant

 

[film495]

the cam's index mark under the FW must be just touching the carb's throttle cam follower bar or roller at the START position

this leaves the throttle plate mostly closed allowing fuel-air to be extracted from the carb's top " low speed" fuel chamber .

the choke can provide extra suction on the LS circuit to start the engine if hesitant

that's perfect. I actually got a minute to do this operation and it was off. I can't say it made it run any better or different, but - now I know exactly the poition that throttle should be in to be in the start position. The stickers indicating start/run are long gone. Knowing where that cam is supposed to be, that's more accurate than the start/run sticker.

It dawns on me, I'm usually trying to start it with the throttle wide open, and that works on my 3hp fine, but maybe this one is more prone to flooding. I could just be flooding it. It sure starts again like it is flooded. I should pull the plugs next time and give that a look.

How does the ignition work? In my head, I'm familiar with 70s Rotax twin 2 strokes from Snowmobiles. Similar, but different. I figured out each coil is it's own primary and secondary coil in one. On the Rotax, they share a coil, and a continuity test with a timing light, tests the whole circiut, through the primary coil, and both sets of points at the same time. Doing this on each side, pretty much indicates that ignition is going to light up plugs with a blue spark. Anyways, that test got you thriough a basic health test of the points and primary coil, without any special testing tools, but a battery and a light bulb, and a few alligator clips. On the rotax, you attach to the circuit, with the wire that connects to the external secondary coil, but here they are one unit, so - I can't visualize how to test the circiut, or do a similar basic continuity test. The old, the light goes on or off when they open or close, but through the coil. Is that possible here or do I need to learn new tricks. uhhhg

 

[Crosbyman]

suggest you download this book...it covers magneto set ups on most oldys but not the 4hp... yet they are basically the same set up wise.

for 20$ you can't get a better manual. download and print & bind locally

1922-1964 Johnson 302231 Outboard Service Manual

Johnson Outboard Motor Service and Repair Manual # 302231 Tenth Edition covers all Models 1922-1964 .pdf download

watercraftmanuals.com

coil primaries are about 1-2 ohms HV pin to either primary wire is 4-8 Kohms

lots of utubes on the subject .

 

[film495]

I'll probably order some ignition parts. I think this ignition is running pretty good. I went over it again, and took my time a bit more, and far as I can tell, looks good. Nice blue spark, gap set correctly, cleaned points.

I did get out an ohm meter and do some continuity testing, but really just to compare side to side, and I remember .4 and .8, but I'm not sure on what scale or off what connections. Couldn't get any readings off any of the coils where the 2ndary goes out to the plug wire. Get a reading between the two lead wires from the coil, but that's about it.

I gotta review and practice with the ohm meter, to be able to pick out a faulty coil better. Having a new one or two of the things, in theory, should give me a baseline to practice with. Testing on the old ones is like, well - I'm not really sure what anything is supposed to read, and I got no readings through the secondary coils, on any of 4 I tested, so - that's gotta be me, cause the coils do work, maybe not fully correctly, but they make spark - so, my test results have to be bad.

It does run a little better with new plugs and having gone over the ignition again, but very similar. I think the carb has a plugged low speed needle, the adjustment knob does nothing, I wonder if I just kept turning it out, if it is so plugged, the needle just isn't doing anything, and I could take it off an it would not affect how it runs.

 

[Crosbyman]

Testing an Outboard Coil with a Multimeter using an ignition coil from the Johnson H or T

Multimeter testing of Johnson outboard coils

pochefamily.org

you can get a digital meter with auto-ranging but see Poche document to understand the process process.

visit utubes on how to use a meter

YOU MUST HAVE 4-8Kohm from the HV pin to either primary

 

[film495]

I had to mess with my voltmeter. It doesn't auto sense the rage, so - getting the 2ndary winding to light up with any reading took a bit. Looks like the 2 coils I looked at tonight are in spec

my meter is wierd. the scale for ohms goes

200
2000
20k
200k
2000k

which maybe makes sense, but it certainly odd. since in the 200 scale, a reading of .7, means .7, but in the 20k scale, a reading of 4.07 means 4,070

I got 4,000 on both secondary windings
and .8 on the primaries

These 2 coils seem to be in spec

I did order up some ignition parts. Can't hurt, more parts to test with.

That is a good document/link.

 

[film495]

I took the magneto plate off the parts motor. Eventually figured out how to test ohms on the coil and they both test good.

Eventually, I'm gonna want to snip some coil wire and put in new. The routing of the cables messes with my head. And the plugs pointing to the left just makes the run that much longer. That can't be right, the plug wires get caught in the latch that way, no way it was assembled that way at the factory. I think I'm gonna swap that when I start replacing plug wires.

What the heck does the little tab on the bottom do? The other part there I looked up under the still assembled one and it is like a clamp to hold the wire in a channel. but, the little metal tab arm kind of looks like it is a spring?

I guess that is the benefit of the parts motor, I can see if I can put wires on that one, before I take apart the running one. I think I have a roll in my garage somewhere? Does it have to be a particular diameter?

 

[Crosbyman]

7mm metallic strand core ...copper is best but metallic is metallic and 2 feet will just add 1-2 ohms at worst (won'T slow down 10,000+ volts to the plugs ..
did you download the Johnson service manual where all this is explained and extensively covered on utubes.

the small tab is there to hold the wires in place.

the design is 60 years old and it worked for 60 years .

have you considered trading up to a nice CD 5.5hp with gear shift ?
also well covered in the big bible and the book CHEAP OUTBOARDS by E.Wawrzyniak. the book is to costly now but it is available in Kindle to download

Cheap Outboards: The Beginner's Guide to Making an Old Motor Run Forever: Wawrzyniak, Max: 9781891369629: Books - Amazon.ca

Cheap Outboards: The Beginner's Guide to Making an Old Motor Run Forever: Wawrzyniak, Max: 9781891369629: Books - Amazon.ca

www.amazon.ca

 

[film495]

apparently that piece is a grounding strip, so says parts diagram

for a 12 foot rowboat, I like the 3 and 4hp, works on a 14 fine. to plane, for me and another, I think I need a 15hp to make that work if the boat is semi-v and about 200lbs, looking to pick one up.

What is a CD 5.5? I have an 8hp 1991 Johnson my Newphew and his cousing make good use of. I had the 8 on a 12 foot aluminum mirrocraft years ago. It planed with just me, but struggled to ge there. I'm 250 and was probably 280 then. A 3 or 4hp motor is about right for that boat. I'm looking for a 14 foot aluminum, just rowboat set up, for a 15hp I don't have yet, and one of the little ones can just be a kicker or backup motor, trolling motor, etc.

 

[Crosbyman]

Oldys 1960s and up in the CD 5.5hp version use a standard tank....great motors . some go free 50$ 100$ if you look around.



if you need bigger and cheap... go AD 7.5 or QD 10hp or FD 15 hp... just look them up on utube.

apparently that piece is a grounding strip, so says parts diagram

see... you found out

 

[film495]

I think one of the 15hp Evinrude/Johnson motors they made from like 64-92, is what I'm going to try to get my hands on. or a couple, we'll see. So many motors so little time.

 

[racerone]

Not sure it is a ---" grounding strip"-----What does it connect to ground something out?

 

[film495]

Not sure it is a ---" grounding strip"-----What does it connect to ground something out?

I'm not sure. Maybe that is the ignition cut off, and it grounds the magneto when the throttle is closed far enough? So, it might be the ignition kill switch when the throttle is in the right postion?