1970 4HP Johnson

[tmosgood]

Picking up a 4HP 1970 Johnson outboard this weekend for $150. Looks like it is a long shaft- I read somewhere this is a modification or a rare set up? Can’t confirm either way. Seller says it’ll run for a bit on starter fluid but likely needs a good carb cleaning, fresh gas etc. I’ll need to check the compression but other than that I’ll probably buy it as a project. Could anyone point me in the direction of some general maintenance points for these engines? Carb clean obviously, water pump, lower unit lube, etc. But is there a good checklist to follow before trying to fire it up? Thanks again.

 

[racerone]

Sorry , but it is NOT a long shaft !!----What is the model # of this motor?

 

[tmosgood]

Model 4R70E….Hmm, weird. I saw a post on here about a similar engine being fitted with a long shaft ? Post here

What do I need to know?

 

[racerone]

It is indeed a short shaft.----A long shaft would have a 5" spacer between lower unit and exhaust housing.-----Hurry to this site---leroysramblings-----Learn all there is to know about working on maintaining small motors.

 

[tmosgood]

Thank you, I’ll check it out!

 

[saltchuckmatt]

Owned the Evinrude version....the only problem with that motor is forward gear only. You start it in gear and be prepared to go somewhere.

Better as a trolling motor on say a 14 alum boat with a bigger older main motor that doesn't like to troll.

Oil mix is richer on that motor too depending on who you believe.

 

[oldboat1]

Get it to idle smoothly as low as you can -- means disassembly of the carb, soaking in a solvent and cleaning every opening. Topside under the silver plug is critical (idle passages). You probably know that the lever on the side is the throttle.

 

[tmosgood]

Picked her up today. All in all, seems fairly clean and quick inspection shows no major parts missing. All levers, teeth, linkages, boots, etc all seem functioning. Pull rope tension is a bit weak. Pulled the plugs and inside revealed a lot of carbon/oil build up (see pictures). What’s the remedy to clean inside? Plugs seemed oily as well. Haven’t pulled the carb yet but I will once it warms up outside.

 

[racerone]

Looks like the block was replaced.----I see nothing wrong with the sparkplug.

 

[saltchuckmatt]

Get it running and then run some omc carbon guard through it.

 

[airshot]

Those older motors ran a heavier oil mix in the gas than newer motors so you will see more oily residue left behind. I can remember the old add a quart of oil to 6 gallons of gas motors, they almost looked like they were on fire going down the river !!

 

[tmosgood]

Yea, I had an old 1979 9.9 Johnson…miss that thing but it loved oil. So 50:1 still?

 

[TN-25]

For 1964 OMC (Johnson Evinrude Gale) started claiming all their motors ran the new 50:1 TCW-1 grade 2-cycle oil (that OMC started selling that year, made by Castrol). It was true for fully roller bearing motors. The 3-horse became the 4 but was only partially fitted with roller bearings through 1977. Better to run 32:1 synthetic if you want to flog it safely, then de-carbon seasonally or so. I broke in a new 1974 4-horse on 50:1 very carefully in stages and it was a sweet & smooth little motor.

As far as long shafts for 20" transoms are concerned, I have attached pics of the early style straight drive (a '69) & the later straight drive (a '74).
The straight-drive foot began as a dealer kit for the Johnson 3 in 1964 and a factory model Evinrude Yaghtwin in

 

[TN-25]

Oops, I blew it during the last edit due to technical difficulties.

For 1964 OMC (Johnson Evinrude Gale) started claiming all their motors ran the new 50:1 TCW-1 grade 2-cycle oil (that OMC started selling that year, made by Castrol). It was true for fully roller bearing motors. The 3-horse became the 4 but was only partially fitted with roller bearings through 1977. Better to run 32:1 synthetic if you want to flog it safely, then de-carbon seasonally or so. Even so, I broke in a new 1974 4-horse on 50:1 very carefully in stages and it was a sweet & smooth little motor.

As far as long shafts for 20" transoms are concerned, I have attached pics of the early style straight drive (a '69) & the later straight drive (a '74).
The straight-drive foot began as a dealer kit for the Johnson 3 in 1964 and a factory model Evinrude Yachtwin, factory for all in 1965.

 

[Crosbyman]

weak recoil is easy to fix...

pull the cord all out
block the rewinder
remove the handle and loop one or two more turns around the rewinder.
reinstall the handle

important to gently pull the handle till the FW rewind gear matches up with the FW ...then pull.

 

[racerone]

There was a 15" extension kit available in the 70's for these motors.-----One issue with these motors is splines rusting out due to lack of maintenance.

 

[Crosbyman]

Picked her up today. All in all, seems fairly clean and quick inspection shows no major parts missing. All levers, teeth, linkages, boots, etc all seem functioning. Pull rope tension is a bit weak. Pulled the plugs and inside revealed a lot of carbon/oil build up (see pictures). What’s the remedy to clean inside? Plugs seemed oily as well. Haven’t pulled the carb yet but I will once it warms up outside. View attachment 375200View attachment 375201View attachment 375200View attachment 375202

for just a few $$$ you can pull the cyl head look inside for any damages on the cyl walls, then remove all carbon . probably cheaper than a bottle of Carbon Guard which I do use in my ETEC. Used quality oils . I run 40/1 on post 60s engines like these..... 4hp are great kickers !

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.

www.leeroysramblings.com

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.

www.leeroysramblings.com

 

[Crosbyman]

for just a few $$$ you can pull the cyl head look inside for any damages on the cyl walls, then remove all carbon . probably cheaper than a bottle of Carbon Guard which I do use in my ETEC. Used quality oils . I run 40/1 on post 60s engines like these..... 4hp are great kickers !

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.

www.leeroysramblings.com

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.

www.leeroysramblings.com

could be wrong here but it looks like a left hand prop...may be hard to find and $$$$ so take good care of it !!

 

[tmosgood]

Looks like I am missing the original high speed adjusting knob…prior owner looks to have put a smaller one from another model? Anyway, I’ve turned over every stone to find one…any ideas where I could get one (aside from buying an entire parts engine?)…thanks everyone for the help.

 

[racerone]

They built 1000's of these motors.----Therefor props are not hard to find.---If in Canada-----evinrudeparts.ca----For possible help on used parts.