TOPIC: Help Installing Starter on Blue Stripe 50 Merc

I picked up a nice Blue Stripe(late 70's I suppose) Merc 50 hp today for a song. The starter was removed for another use but luckily I have one from a 89 40 Classic that I am parting out after the oil injection failed and fried the pistons etc. Problem is I am not sure where to connect 5 wires from the motor side harness.

The starter has 3 posts...top, near bottom, and slightly above bottom. I figure that the top post is negative and connected to the block on one of the top starter mounting nuts. The very bottom one is the Neg cable to the battery. The third near the bottom is Positive and has the red cable to battery.

Now where do these 5 little wires from the harness connect?

There are 3 black(one has a very small connector on it) one red(I assume goes to positive post on starter, and one yellow with a red stripe(choke solenoid maybe?).

Have a look and hopefully give me some hints. Thanks, Tim

I'm not sure that the '89 40 classic's starter has the correct bendix gear needed for the '70's 500 and if that is the case - you can't even rob the bendix gear off a '70's 500 starter and put it on the '89's starter. I 'think' that the later series Mercs went to metric.
As for your wiring question,...
What did the wiring harness originate on?
The (3) small blacks are most likely (-) grounds. One to a small terminal on the starter solenoid, one to the switchbox case, and maybe one to the engine block or the Mercury Safety Switch???
The small red should not be connected to anything until we can determine what specific internal harness you have & what specific ignition you have. It 'looks' like it have a larger end on it suggesting it would go to the primary solenoid terminal where the large red cable goes - but just a cautious guess. It might be a power lead for trim???
The yellow with red stripe coming into the motor from the harness suggests it goes to the starter solenoid's other small terminal on the starter solenoid.
(earlier model Mercs used a yellow with red stripe wire between the stator and the rectifier - but they came in pairs of two and did not go into the internal harness.
Thom

Tim I think you need to elaborate some more with detailed pics. Serial # and photo of the whole motor, where your starter mounts, ignition etc....
The more information and photography the better.
Jim

Yea Jim you are right I need to elaborate.

I think I am getting closer. Not only the starter was removed but also the solenoid. So I grabbed the one from inside the power pack on the newer 40.

So this is what I have so far.

Starter has two posts....top and near bottom. Top is ground which has a cable running to one of the upper starter bracked mounting bolts. Bottom is hot(+) which connects to one side of the solenoid.

Solenoid has two main larger posts and two small. Battery + connects to one of the large and starter lower connects to the other solenoid main right? Now for the wiring harness connections. Heavier gauge red goes to one of the solenoid main posts for + connection to key/switch.(I assume on the battery side of the solenoid right?

Yellow with red line goes to one of the small posts on the solenoid and a black wire(with very small connector) goes on the other small post on solenoid.

Now the big question.... I have two small black wires out of harness(one connector smaller than the other) left over. I am betting at least one is grounded but where would they go.

Here is a few pics.

THis is the starter still in the newer 40 classic"



Here is the starter in the 50. At the bottom of the starter the neg to the batter is connected to the left lower mounting bolt. The upper right bracket mounting bolt is connected to the upper post on the starter(behind you cant see). The positive from the battery connects to the right side solenoid big post and the left side big post goes from solenoid to starter lower in pic.

The two left over blacks out of the harness are taped with painters blue tape. Where do they connect?

Bear with me and thanks for your patience. I only have manuals for older 55 Marks with magnito and I have a newer manual up to 40 hp but only two cyl? Thanks.

Starter has two posts....top and near bottom. Top is ground which has a cable running to one of the upper starter bracked mounting bolts. Bottom is hot(+) which connects to one side of the solenoid. ***YES YOU ARE CORRECT***

Solenoid has two main larger posts and two small. Battery + connects to one of the large and starter lower connects to the other solenoid main right? ***YES***Now for the wiring harness connections. Heavier gauge red goes to one of the solenoid main posts for + connection to key/switch.(I assume on the battery side of the solenoid right? ***YES***

Yellow with red line goes to one of the small posts on the solenoid and a black wire(with very small connector) goes on the other small post on solenoid. ***YES YOU ARE CORRECT***

Now the big question.... I have two small black wires out of harness(one connector smaller than the other) left over. I am betting at least one is grounded but where would they go.
***The black with the larger lug connector will go to a 1/4 x 20 bolt nearest to it*** The black wire with the smaller lug will go to the switch box plate. You may need to extend it or simply find a spot for it to connect to. ***Are you sure it is not a black wire with a yellow stripe?***

OK Jim now we are getting somewhere. I just need to figure out where to connect the black wire with the little connector to. I will run back out and look to figure out where to connect to the switch box plate.... do you see anything in my last picture? Are those black wires both grounds? No there is no wire with a yellow line ...all three were just black...

Thanks so much...Tim

Ok Jim how's this look? I connected one of the blacks with the bigger connector to the upper right starter bracket and the other one with the small end across the starter to the lower right mounting bolt on what I assume is the switch plate(where the coil wires run into?)

Ok as I have no patience I went ahead and hooked it up to the battery and hose and tank and gave it a try. It is turning over and engaging the starter but kind of flaky ...gotta play with it a bit and try several times etc. Will check all connections tomorrow in the light.

Problem is ...no spark as far as I can tell. Before I even hooked up the fuel tank when I was just trying to make sure the starter would crank it, I squirted some pre-mix into the top three cyl's assuming that it would at least kick but no sir.

Walked away but then had an epiphany remembering that there was a on/off kill switch on the control box that probably one would hook up to a lanyard or whatever and sure enough it was in the off position. Ah hah..problem solved. Not so fast....it is still not firing.

Still wondering if the wiring is all right ...especially those wires in the harness?

Enough for tonight. .... THnaks for the help.

Tim

Happy Fathers day tomorrow to all.

Tim,
I couldn't find a wiring diagram specific to your 4 cyl unless it originally had an internal harness that went through the side of the lower pan and plugged into a cobra-head type external harness.
I have attached copies of several wiring diagrams of the type of ignition you are working with.
The yellow with red stripe solenoid wire suggests the internal harness you are using is the type with an eight pin in a circle plug-in that mounts inside the cowlings and has the 'industry standard' wiring colors that were different from the earlier cobra-head type harnesses.
Anyway - I'm sure that if you study the attached harnesses you'll be able to identify which one is closest to what you're working with.
Thom

your wiring at the starter etc...looks OK but as Doc indicated need to know if you have the cobra head side plug or are the wires coming through the front bottom left (as you are looking at it) cowl of the motor. No spark could mean dead switch box, stator, or trigger.

From the SN (5799264) I figure it is a 1981 btw.

The wiring harness connector is not the older cobra that connects on outside of cowl but rather a smaller round 8-pin that goes inside the cover and connects to the female connector under the starter. Here it is just connected outside for testing.



And here are the controls:



Here is a list of the 8 wires on the motor side of the harness and what they are connected to:

These I found connected already:
1) Red => Rectifier
2) Grey => Rectifier
3) Black/Yell => Switch Box
4) Yellow/Black => Choke Solenoid
5) Black/Yellow => Mercury Switch I believe

These were dangling with no starter or solenoid in motor and
where I connected them:
6) Red => Large terminal on Solenoid (battery side )
7) Black => Small terminal on Solenoid
8) Black => Gnd on starter motor bracket bolt
9) Black => Gnd on switch box bolt.
10) Yellow/red => 2nd Small terminal on Solenoid

As you probably know by now - this ignition creates its own electricity and does not need a 12vdc battery electricity to create the spark.
If the control box is attached and the key is in the 'ON' or 'START' position and you don't have any spark, try these (2) tests before proceeding to individual tests of the switchbox, coils, and trigger.
1) Disconnect the white with black stripe wire from the switchbox to identify whether or not the 'BIAS' ciruit has failed & test for spark.
2) Dis-connect the black with yellow stripe wire from the switchbox and test for spark. Be aware that while this black with yellow stripe wire is disconnected the Merc can start and continue to run until the black with yellow wire's terminal on the switchbox is shorted to ground (-).
After these tests, since you don't have spark on any of the (4) cylinders, I would suggest begin component testing on the low side of the stator as per the manual.
See below. (if you can't read the attachments due to size - write direct and I'll send them to you larger and easy to review.
Thom

Thanks Thom,


I tried the first two tests but no luck. BTW the white/Blk wire casing was really corroded(rest seem good) and I have re-wrapped it yesterday.

I can read the other docs fine and will start on them next. Good news is I do have all of those parts as spares should I find something bad. Bad news is I still have not purchased that special Mercury Flywheel puller and will be looking to do so online tonight. The last 2 times I have needed one I made a 70 mile round trip to a friend to borrow his.

Happy Dad's Day All.

Tim

From looking at this pic, that red wire at bottom, would be the lead going to the selinoid.
Looks a little lightwieght for the purpose....the starter won;t be able to draw the right amperage, which may be why its not firing up as it should...my 2cents.

I have 50hp blue stripe '76....if you need any photos let me know.

"From looking at this pic, that red wire at bottom, would be the lead going to the solinoid.
Looks a little lightwieght for the purpose....the starter won;t be able to draw the right amperage, which may be why its not firing up as it should...my 2cents."

It looks to me like that small red wire is not the primary for the starter or the starter solenoid.
If you look carefully you'll see that there is a large black wire with a piece of red shrink wrap on it that is the 12vdc primary to the solenoid. Then there is an all black large wire between the solenoid's secondary large terminal and the 12vdc (+) terminal on the starter.
I'll bet that if that small red wire is taken off the primary 12vdc terminal on the solenoid - it would still have 12vdc showing with the harness plugged in and a battery attached.
If so,...It would be the 12vdc primary via a fuse link going to the power trim solenoids or relays - if PT is installed - OR - if this powerhead has a regulator installed - that smaller red wire (if it has 12vdc constant as previously explained here) it could be what the (2) red wires coming out of the regulator attach to on a terminal block - or - if this motor simply has a rectifier - that constant 12vdc small red could be the wire that goes to the (+) terminal on the rectifier.
Suspicious though due to the larger eye on the end.
Full of MYSTERY I find myself today,...Hum-m-m

if i remember mine had a fuse in the system and if it blew i had no spark. many years ago.

Thom is correct. There is a direct positive to that solenoid post from the battery. The small red wire comes out of the wiring harness and was dangling nowhere so I placed it on the solenoid assuming it might need 12V+.

There is another small red wire out of harness(and a grey one) that were already connected to the rectifier(I assume it is the rectifier....small square box below the Solenoid.

As for a fuse... I have seen wiring diagrams that have a fuse on 12V + to solenoid but I don't see anything like that here.

i clicked on picture to enlarge...yep see it now...my 2 cents was worth much sorry.

Ok Thom I finally got back to trying some more of your diagnostics. I started with the Trigger figuring that since I had no spark it was unlikely all coils bad, and stators are usually pretty hardy.

The first set of pairs White and Violet showed continuity acceptable at 8.4(between the 7-10 range)
The second pair Brown and White/BLK failed.. no continuity. Remember that this white/black was also the wire that had its insulation pretty much disintigrated and I wrapped it. I even double checked on the spare trigger I have and yes they are both within range as described.

So while I wait for my flywheel puller to be delivered, I'll check the Stator wires while I am at it.

THanks for you kind assistance as always.

Tim

Got my flywheel puller in the mail today(great deal...Made in USA and includes a lifting ring....$34).

Anyways...replaced the trigger...pretty straight forward deal. Put it back together and two things.
1) still lingering issue with the starter being intermittent ...gotta play with the key and it cranks well when it wants to.
2) thought I had my spark issue as it did kick and run for a sec probably burning the premix in the cyl I squirted in. Then it wouldnt kick no more...even with more premix. I pulled the top plug and wired it up with soldering wire to ground to check for spark. Turned it over and yes spark and the motor started running on the 3 cyl...albeit labored and chugging for say 10 secs or more until I turned it off.

Now I put the plug back in and no kick. I can see spark but how can u tell with these NGK's that don't have the little arm(sorry the name of these flat plugs escapes me at the moment).

I shouldn't have to do anything with timing should I if I just pulled the flywheel and installed the trigger and put flywheel back on keyway without doing anything else?

I'll keep playing but thought I would throw some thoughts out there as I putz with it.

Thanks,
Tim

Getting nowhere fast with this motor. Getting a manual btw).

Lets leave the no-spark thing aside for a minute while I tell you about the no-stop thing that happened in the dark last night. I figured I'd get a better indication of spark in the dark than in daylight. So I went out and started cranking it over (top 3 plugs out and grounded and 4th coil wire connected to spark tester.

I was getting intermittent and pretty weak spark on various cyls but then after about my third crank over, I released the key back to on and the starter motor was still spinning the flywheel...so I turned the key to off.....still spinning...turned past off turning the ign cyl in the control box....quickly dropped the controls and pulled the sparking neg lead off the battery to stop it before I burnt out the starter etc.

What the heck would cause that?

Back to the no-spark. As I was replacing the timer with the newer one I had on hand, I decided to upgrade a few other things cause I had them and they are 10 years newer. I swapped out the coils and the switch box also. I know I have all the wires correct connecting to the switch plate(easy enough when it is printed right on the face what color goes where...only one that threw me was what they call black/white to the trigger...it is actually just a lighter shade of black but anyways...)

Only thing I haven't tested is the Stator yet. Will do so this morning...shoulda thought of it when I had it off replacing trigger yesterday DUH!.

I certainly have a much better working relationship with magnito's and points than I do with these CDI motors.

bad starter relay

Where is the starter relay? You are not referring to the solenoid are you?

yes i am

dave bernard wrote:

bad starter relay

This could also explain the intermittent starter operation.

The starter is now engaging regularly and the motor actually started running after I replaced Stator and checked spark. Thats the good news. Bad news is..as soon as it started up the starter kept on spinning so I had to remove the + battery lead again and it stopped. When I immediately touched the cable to the battery it engaged the starter again(with the key off)....as in the solenoid is open(or it is closed) without the key being in start position.

Gonna do some searching on Iboats forum now...probably is solenoid right? It isn't anything to do with the keyed ignition as I was using another set of controls and it has happened with both now.

see if ther is juice to the small wire on the solonoid.should be none with the key in run or off

I am just heading out to test that and if the solenoid is stuck closed with continuity across it. If solenoid I found one at Napa ten miles away.....Merc dealer 1 mile away was out of course.

Stay tuned.
Tim

Solenoid was indeed stuck closed....continuity when key off...tapped with screwdriver and it opened again. Got a new on at Napa and she is cranking like crazy. But unfortunately not starting. Coughs and sputters for a few secs once in a while but then other times just cranks even with pre-mix in the cyls.

If it was consistently kicking when spraying the cyls and then dying I would move directly to cleaning the carbs etc but it is not. Gotta concentrate on spark some more I guess.

So it goes......or actually doesn't

Tim

Got it to fire up several times with pre-mix....last time roared at full cold throttle then died. So now it a deeper dive. Carbs are off and cleaning begins tonight. I am pretty familiar with these little Tolletson carbs with the integrated fuel pump...albeit one at a time on the 9.8's and 9.9's I have worked on.

Stay tuned.

Tim