1972 Johnson 40hp no cooling water flow

[Bstrong1402]

Put the ears on the intake for my 1972 Johnson 40, and no water from exhaust or the two ports below the exhaust. Plus, lower end oil mixed with water (milky) leaking near prop.

 

[racerone]

Are you sure it is lower end oil ?----Checked the lower unit for water in the oil ?----Time to install a new impeller I think.-----What type of muffs are you using as the typical muff set-up does not work on that motor ?

 

[F_R]

One of the simplest and most trouble-free of outboard cooling systems. Replace the impeller and then get it in the water where it was designed to run.

It would be very rare for that one to be plugged up.

 

[oldboat1]

This motor new to you? If so, would definitely want to replace the impeller as a first step. Otherwise, you might dip the l.u. deep in a barrel and try it carefully again -- if, for example, it ran well for you last season and/or you know the impeller was replaced fairly recently (say, two years ago, or so). You should see water out of the exhaust port on the leg immediately after start up. Run it only at idle or high idle.

The l.u. oil should be checked for water, but could do the above testing first without risk. If there is water, you can pressure test the unit yourself to locate the leak.

 

[Bstrong1402]

Thanks for everything. Motor is new to me. Last owner said he test ran it last season and everything was good. I’m using round ears. I’m thinking I should renew the impeller and lu seals.

 

[racerone]

Round muffs are not the best test method for that motor.-----Main water intake is the screen behind the prop..

 

[Bstrong1402]

I didn’t know about the intake. Thought it was the screen on the left side of the motor held on w/ three screws...just above the biggest horizontal plane. I tried to use a big trash can, but the lower unit is too long fore and aft for it to fit. A friend is bringing his big tub to work tomorrow. I have ordered a new impeller and new seals and gaskets to rebuild the lower unit. The manual should be in the mail when I get home. I truly appreciate everyone’s help. I am the new owner of a 1972 Starcraft SS 16’ and live in Traverse City, MI

 

[Bstrong1402]

Got home last night and checked on the intake Racerone pointed out in his last post. Don’t I feel like a boot. I failed to look closely at my own motor. I’ll test run it again tonight in the water where F_R and everyone else told me to test it. There is still the issue with the milky oil coming out in the prop area, but I have new seals to put in after I run it. Thanks shipmates. (I was a Quartermaster, not a MK)

 

[David Young]

The milky oil coming out of the exhaust is normal. Milky oil in the lower end lube is bad.

 

[oldboat1]

good opportunity to buy an infrared tester to check head temps -- look for 120-140 or so after warm up, never hitting 160F. If too hot to touch, it's running too hot. Not good for the motor, but might be welcome up in Traverse City this time of year. (I'm in upstate NY -- also waiting for Spring.)

 

[Bstrong1402]

OK guys. I have taken the prop off, removed two sets of six bolts from two levels of the lower unit and it still will not come off. What am I missing?

 

[racerone]

For one thing it is NOT a 72 model.---You have to post a model # to get accurate help.----The rear cowling has to come off to find a long 3/8" bolt.----And you have to disconnect the shift linkage !!

 

[racerone]

Paint is faded perhaps.---But it does have that 1967 look about it.---Might even be an electric shift model too.-----Does it have the belt driven generator ?-----And why are those 2 mount screws missing ?

 

[Bstrong1402]

Thank you, Racerone. I did end up taking the rear cowling off and finding the 3/8” bolt. It does have a belt driven generator and electric shift. There is no model number on the motor, but there is a number on the freeze plug. J2740710. The mount screws are off because I was looking for any possible connection that could be holding the lower unit on. I will put them back in right away.

 

[hardwater fisherman]

If the cowl has original graphics and paint post a photo of it. That number on the welsh plug is probably the serial number.

 

[racerone]

My crystal ball says 1967 based on colour of the paint !---And yes the gearcase appeared to be electric shift to me. Where on the motor did you look for the model # -----those rarely fall off.

 

[Bstrong1402]

[No message]

 

[Bstrong1402]

I looked on the left side of transom mount

 

[hardwater fisherman]

It appears to be as racerone says a 1967 model. Maybe model number RKL-29. There could be a plate on top of the swivel bracket.

 

[hardwater fisherman]

[No message]