Evinrude 40973R 40HP - Selectric shift - reverse goes forward!

[stevepamboukes]

Hello all!

Thanks for your help so far - i got started here with my first post (link below) and it was a huge help. Now ive gotten a lot of enjoyment out of this rig, and my engine has been pretty darn reliable! A good performer too!

Yesterday, though, may have been the last day of the season for me:

I was pulling in to dock, shifting between F and R quite a bit to jockey around and navigate a nasty eddy. All of the sudden, reverse stopped working. I was able to dock safely, and eventually navigate back home... but needless to say I'm a little disappointed about my transmission problems!

When it first happened, I had forward, neutral, and NO reverse. I checked out the wiring as best I could on the fly, opened the selectric shift box, checked wires, all looked pretty good as far as I could see. Then, kind of out of no where, reverse started putting me into forward. Not really an improvement, but I was just sort of happy that at least something was going on in there. Maybe not a good thing at all. I was able to get home nonetheless and the engine seemed to run fine in forward.

So I still have much to research on this problem, I expect I'll check the wiring again, but after that I may need to get into the LU/transmission situation and see whats going on in there. I figured I would post here first and see if anyone had suggestions for obvious failure modes that would lead to this. Speaking of wiring, does anyone have a description of the selectric shifter wiring configuration? Ie, which wire does what for F, N, and R? That will be the first place to start...

 

[jimmbo]

Sounds like the push buttom shift has some issues internally. While not quite extinct, the remaining replacements can fetch a Kings Ransom,

Red is hot.
Green is Forward
Blue is Reverse

 

[F_R]

Since it was working before all this happened, it would seem reasonable to assume the push button switch has gone kaflooey. Or sometimes the electric cable running down to the lower unit burns up inside the exhaust housing. It is highly unlikely that the trouble is internal in the gearcase.

While you are troubleshooting, remember it can cause serious damage if voltage is applied to both the blue and green wires at the same time while running. That puts it into both gears at the same time and something will probably bust.

 

[stevepamboukes]

No Title

Jimbo, thanks for the "pinout". So to be clear... neutral would be that red is not connected to anything. Forward would be red connected to green. Reverse would be red connected to blue. Yea?

I saw another post, advising that I connect +12VDC to each wire (one at a time!) to see if the prop locks up one way or another. That would tell me if the fault was in the selectric shift control, or in the lower unit.

I would love if the problem was in the controller! I'm sure I can repair or recondition that mechanism if needed. Without knowing exactly how that little solenoid valve or whatever it is works down there, I guess I didnt have much reason to think it was any more likely to be the control over the something in the gearcase. Till I do more diagnostics, I can't rule out one or the other...

I should add its got fresh lower unit oil with less than 3ish run hours on it. I can check levels but should be fine on oil.

PS here's me and the boat!

 

[racerone]

There are no solenoids in the lower unit.----There are electromagnets that exert a pull on a spring.-----Oil / oil level does not matter for shifting.----Unit still shifts if all oil is drained.

 

[stevepamboukes]

Ok, right on, electromagnet is kinda what I meant by solenoid. while we're talking about it... shift controller juices electromagnet -> electromagnet pulls spring -> spring does....? what exactly to actuate F N R? I thought I read it controlled a hydraulic valve that allowed fluid to cycle thru one passage way or another...

 

[racerone]

You are mixing up the working of the Hydro-Electric shift unit with the one installed on you motor.----No hydraulic valve of any kind in your motor.

 

[jimmbo]

Be careful if you buy a new/replacement switch, the ones for the Electric Shift are different from the ones for Hydro-Electric Shift. Problem is Evinrude referred to both systems as 'Selectric'.
You seem to have the power routing sorted out. Appling power to one the wires and spinning the prop has to be done carefully, first the motor could start, which makes for a very unhappy day if any limbs are touching the prop. So disconnect the spark plug wires and ground them. Since the gears aren't turning, you have to spin the propshaft counter to the normal rotation for whatever gear you select, that will cause the spring to wrap itself around the hub and then the prop will become hard to turn as it is now in gear.

Here is a link showing the gearcase, it is from a Johnson Brochure, but except for the control box the units are the same
http://www.boatinfo.no/lib/johnson/b...hnson.html#/12

 

[F_R]

One end of the spring is attached to the gear (fwd or rev). The other end wraps closely but not tightly around a clutch hub splined to the prop shaft. An electromagnet magnetizes the clutch hub, pulling the spring to it. Then rotation of the gear/spring causes the spring to wrap very tightly around the clutch hub, causing the hub to rotate along with the spring/gear assy. Think of it this way: If you wrap a rope several turns around a tree, you could hold one end of the rope with your fingers and exert enough pull on the other end to spin the dadgum tree right out of the ground---or bust the rope.

 

[stevepamboukes]

ok - great thanks for that brochure and diagram! That clears the function up for me. So its a purely electro-mechanical setup.

Im not sure when I'll get a chance to chase this out but this oughta be good info for me... maybe i'll get back in the water once more this year!

I'll post my findings.

 

[stevepamboukes]

ok so i was impatient. I shut the power off on the boat, left the shift control in neutral. I went to the blue/green connections down at the engine, peeled the rubber protectors back, and used jumper cables to ground the negative and put +12VDC on the blue and green wires, one at a time. Again, both allow me to rotate the propeller in the REVERSE direction, indicating that both wires are putting me into forward.

Check my thought process here... doing the test that way... that does take the shift control right out of the equation right?

Best theory right now I can think of is that the blue and green wires are crossed somewhere, so when you juice one, it juices the other. From what I hear, thats not a good thing, particularly if the engine was running when that cross wiring happened. I've only done a cursory check of the wiring so far, but I haven't seen any damage or red flags yet. If I wanted to buzz them out using a continuity test....? Is it safe to assume that the blue and green circuits are independent of one another? So if i do a continuity test between green and blue, they should read open circuit?

PROBABLY BAD IDEA: could I put a reverse voltage on the forward wire (green), to maybe pop the thing back into neutral/reverse? Probably a bad idea.

 

[stevepamboukes]

aaaaaand more diagostics:

i opened up the selectric shift control and disconnected the wires entirely. manually connecting purple (hot) to green, I get a nice little spark and the prop goes into forward. manually connecting hot to blue, I get nothing, and the prop does not lock up at all. Same for back at the connections at the engine...

so is my reverse coil shot?....

if I have to get into there......?

I haven't taken the rubber off the selectric switch so I dunno if thats a problem... but either way... seems like my reverse is shot.

 

[stevepamboukes]

... buzzing out the switch... switch appears functional effectively switches the + terminal over to either the F or R terminals, as it should. switch does not connected both F and R terminals to + at the same time.. so on the workbench, at least, the switch appears to be functioning normally.

 

[racerone]

??--When there is no voltage applied the clutch spring disengages by itself !!-------Time to do an ohm check on green wire and to the casing.-Then blue wire and to the casing.--No guessing is needed, just report the values you get..

 

[Guest]

If memory serves me correctly, the 1973 OMC motors 50 hp and up had hydro-electric shift, (lever operated), this is not be confused with "Selectric" push button shift of the late 60's.

On the 73 models, if the "electric" assisted shift stopped working, Legend and Lore has it, you should still be able shift F-N-R, but with more effort.

Are there any shift solinoids on that motor? a parts diagram would tell you., you may have one thats gone bad.

BRP still has all the exploded parts diagrams and (latest) numbers for the motor on their BRP catalog website. I can still get anything I need for my 1973 25 Johnson.

Hope this helps.

 

[racerone]

Hydro-electric shift was never ever installed on any 40 hp motor.-----------And the 73 and later models were NOT ELECTRICALLY SHIFTED at all.--------They used a shift cable to move a shift servo that was oil pressure operated.------And yes they were mechanically operated and would still shift if there was no oil pressure.-----The 73 and later motor had the term " POWERSHIFT II " on the label.--------------But not electrically operated !------And there are no shift solenoids on a 1969 40 hp model.----Just the electro magnets.

 

[jimmbo]

Electric Shift
1962 -1968 on select V4s
!962 - 1970 on select 40hp

Hydro Electric
1968 - 1972 3cylinder
1969 - 1972 V4s

Hydro-Mechanical(powershift II)
1973 - 1976 135hp
1973 - 1977 or 78 85hp and 115hp

 

[stevepamboukes]

with the wires still disconnected from the control switch, resistance reads the following:

green to ground: 8 ohm

blue to ground: 40 kOhm

green to blue: open loop.

big difference there. what values am I shooting for here? Looking like that blue coil is toasted? not sure why switching to forward would have put me in reverse...

I don't suppose getting at those coils is as easy is taking off the prop, then the plate on the motor?

 

[stevepamboukes]

hmm thought I posted this but maybe it didnt go thru....

disconnected the wires from the selectric control switch, and resistance is as follows:

blue to ground: 40kOhm
green to ground: 8 ohm
blue to green: open loop

big difference there. Looking like blue (reverse) is toast? what values am I shooting for?

still dont quite get why selecting R would have put me in F.... i checked the switch and it functions normally

I dont suppose getting at those coils is as easy as pulling the prop, then pulling that front plate off the motor eh?

 

[jimmbo]

Assuming the wires you are measuring are the ones going into the lower unit. The green to ground is nominal. The blue to ground is out of spec. Green to blue should have been around 16 ohms. The cable(2 wires) may be heat(exhaust) damaged, or was damaged inside the case itself. Disassembly is most likely in the future, no it is more involved than just removing the back cover. But it is a lot easier than some of the later cases