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Mercruiser 140 starter

K

kettles

New member
OK, First off the boat is an 86 Four-Winns Freedom 160 with a Mercruiser 140 and sterndrive. Transom assy SN A694219, Motor SN A652120. Drive unit SN basically illegible, I would guess DB412398 but it would take some serious forensics to tell for sure. Anyway, so a few years ago it was left without being winterized, and of course the block cracked (opposite side of spark plugs). I prepped and welded it with nickel wire, and then my dad took it to a mechanic who checked it out and said it seemed OK, although I missed a crack which we found after running it (after I cleaned the paint off before welding, I couldn't find one of the hairline cracks). Anyway, it sat the rest of the year, and the next year I pulled it from storage and tried to run it. It took two 750CCA (deep cycle) batteries tied together to get the starter to turn it over. It ran, but wasn't charging. So it went back to storage.

OK, so now a year later I have basically taken possession of it from my dad, as he doesn't want to put the time/money into it. I am happy enough to make it a project as I love to be on the water and its a fun little boat. I recently bought a house and have moved it from storage to my back yard, so I can work on it.

I tried to get it to turn over, and even with two batteries it didn't want to, it clicked a little, but no go. I pulled the spark plugs and tried again. It will turn over, but seems slow and not as vigorous as it should. Now, I obviously straight away am suspicious of the starter motor. I was using the same two batteries as I did last year, freshly charged, but I they may have some lead sulfation and I don't rule them out completely. They can be checked at an auto parts store.

I pulled the starter motor, but I don't want to just replace it straight away. This block has been cracked, and welded, so I am weary of the internals dragging from warpage. Now it did run last year, and it seemed to work fine right after the repairs, but I cant be too sure. I know I can check the starter for operation on a bench, but that doesn't help me under load. And I don't know if the engine is dragging and the starter is fine, or if the starter is bad and the engine is fine.

So I want to try and turn the motor by hand and feel it, but there is not a easy hex nut on the front, and the engine mount is kinda in the way to begin with. Any suggestions on checking if the motor turns like it should? Any good inexpensive replacement starters?


Also, I need a new alternator, and since the wiring to my Mando unit (PN 98555, 55amp) one is partially missing. The Mando had 2 studs, and 2 wires coming from the box on the unit. however there were remnants of one more wire that had broken off at the grommet, and wasn't used. I don't know what they all did and there was even a wire in the harness that had just been cut off and not used, I would rather just replace the unit with a single wire self regulated model. I was wondering if there would be any problems using with a single wire unit, I would just get something inexpensive.

Thanks!

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For safety you will need a marine starter.-----Has to do with preventing sparks.------If you insist going with cheaper automotive you should also consider a parachute as equipment for your boat.
 
Bring both the starter and the alternator to a rebuild shop, short money.

The alt, the large insulated 1/4 20 stud is output to the starter solenoid/battery connection +12 ORANGE 10 or 8 gauge wire.

the other stud is ground

the two wires coming off the cover are, Purple (12 volts or ignition on) same wire that goes to electric choke. If you have a point ignition do not connect at coil +!!. The other wire should be purple with a red stripe and it connects to other wires in the harness of the same color. I believe the purple is 12 volt sense and the purple with red is excitation. I could be wrong as it may be the reverse but as long as wire colors match you will be good.

Also for testing you don't need the alt to try to turn it over with the starter.

The harmonic balancer should have threaded holes in it, Get some good strong screws and screw em in and use a large pry bar to rotate the motor.

Unless water got into the cylinders the motor should turn over. WHat does the oil look like? If water is present it may be time to look for a new block.....
 
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Oil looks good. I know the motor turns over, the starter managed to turn it with the plugs out, but if the block is warped and the crank is under tension it would be harder to turn over. I seriously doubt that is the case, but I am have had a little voice in the back of my head for the last year that has been worried, and I don't want to put too much time in this motor if the block is bad.

I honestly don't even know where to begin to find a shop to rebuild the starter, lol. I guess I start calling automotive shops...

Ill try the bolt and pry bar method. Any suggestion on bolt thread size so to save me trial and error ;). I don't know if these things are more likely metric or SAE.

Here is a picture of the harness. The purple one was not connected to it so it may well be at fault for the lack of charging, but the alternators wiring is pretty much gone too.
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Would a place that rebuilds alternators be able to rebuild this one? The wiring in the cap there is locked in by some type of resin, so I don't know if you could get it out. The black wire to the grounding post is the only one left with any wire, and its insulation is pretty much gone. The snub of wire in the picture had a blade connector on it connected to the pink or red wire pictured above. The third wire is doesn't protrude at all any more.
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yup purple wire needs to connected.

don't know the thread size off hand but it should be SAE not metric......

Look in yellow pages or do a google search of you local area......Where ever that is???????????

Oh and the two wires coming out of the cover should have had bullet connectors on them with heavy shrink tubing.
One wire with a male and the other with a female coming out of the cover. That way the two CAN NOT be mixed up!!

This is what happens when a back yard boat owner does when not understanding the method behind the design.....they cut wires and simply splice them back together eliminating the original set up......also they tend to use the WRONG color wires because it is all they have around the house......seen this many times.....
 
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Ah, I don't have my personal information filled out. I'm in Louisville KY.

Thanks for the help. Ill keep this thread updated.
 
The regulator is a cheap replacement and i just might have one left .dont even bother trying to get the epoxy out to repair it.
 
The Delco 10si single wire Marine Alternator is a good inexpensive replacement. They do require an initial RPM bump in order to become excited.... but it's not an issue.
Once excited, they will remain excited until shut down.

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Don't spend a dime on a "non-gear reduction" starter motor today.
Instead, find a HTGR/PMGR replacement motor.
The armature will spin approx 3 X's faster than the non-reduction motors........, and with the gear reduction it will spin the crankshaft at a bit higher RPM.
(example only)
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