Dreaded 1990 50hp Force OB

[diver2diver]

Issue was owner was cruising down the river and it shut down, during the time of the owner trying to get it restarted he burn out the starter motor and he replaced with a new starter. So he brings it over to the house and I first check compression (checks Good over 145) then I check spark and no fire.So nowthe fun part begins I check the wire wires off of the coils appear good. Pull the plate holding the coils and the power pack and everything appears to be good but do find that two wires the white/red stripe and white/ yellow stripe has some brown burn spots (no bare wires just on the coating) just about an 1/2' from the pack. I cannot check the DAV off the stator has I do not have the test equipment. But I tried to check the stator OHMS however could not get any readings. My questions is I am fairly certain that the power pack is bad but I cannot not with 100% certainty tell and second is the reason it is bad from the stator neither parts are cheap to have the owner get without being able to show him why they are bad.

 

[pnwboat]

Make sure you disconnect the stator wires when checking resistance. There are several stators used on this motor and checking them is sligtly different depending on which one you have.

If you have a Blue and Yellow wires from the stator, you should read across the two wires disconnected and see 680-850 OHMs.

The other type of stator has Blue and Red wires. This stator has a high speed winding, and a low speed winding. Disconnect the two wires and read from the individual wire to ground. One should read 3250-3650 OHMs to ground. The other should read 75-90 OHMs to ground.

The third type has Blue and Blue/White and Red and Red/White wires. Check the resistance from the Blue to Blue/White. It should read 3250-3650 OHMs. Next check the resistance between the Red and Red/Wite. It should read between 75-90 OHMs.

If you're not seeing those readings, then the stator is bad. As for the power pack, I'm not aware of any test that you can perform with a meter.

Also make sure the magnet(s) that is glued under the inner circumference of the fly wheel hasn't come loose or broken or missing.

 

[diver2diver]

The only color wires I have are brown/blue stripe and brown/ yellow stripe and yellow wires. Unless I am checking the wrong ones. NO blue wires any where I have seen.

 

[Jiggz]

No Title

You are checking on the right wires and you have the "D" type wiring diagram for the 50 HP (bottom one). Anyways, here's a diagram. The resistance reading should be taken between the brn/yel and brn/blu wires and it should be 680~800 ohms. However, I see a black ground wire. So if you do not get any continuity between these wire pairs, you should try reading each wire with the black wire. The yellow wires are for charging and are connected to the rectifier.

 

[pnwboat]

As per the diagram that Jiggz has posted. Brown/Blue stripe is the same as a Blue in my first example and the same for Brown/Yellow stripe. It is the same as Yellow.

 

[diver2diver]

Ok I have checked four times now the OHMS on the wire to wire part to Brown/Blue stripe to Brown/Yellow stripe and get a reading of 0. BTW the each of these wires are labeled 1,2,3,4, with 1 and 2 being the Blue stripe and 3 and 4 being Yellow stripe. The only thing I have not done was to ground. But I am not sure on this one as far as to which ground to to. But if this is the case is it wise to change both the pack and the stator? What else am I not thinking about?

 

[diver2diver]

Ok here's the update found out the grounding wire was burned though out it's run from the solenoid to the terminal block. Also the interlock wire Yellow/Red strip was melted to the rectifier to the engine block. I get no resistance on either side of the stator wires or to ground (open). So my thinking is the Stator is shot, bad pack as well wiring needs to be fixed. So does the cost of parts justify repairing this engine or not?

 

[Oregonbayliner]

Replace stator. If runs then your good if no run then replace power pack start with the less expensive stuff and work your way up. Replace wires that need replaced aswell

 

[jerryjerry05]

Here's the test procedures. Sounds like the stator might be your problem. E-bay or Craigslist for used parts. There was another site someone posted with real cheap stuff, I lost the link, maybe someone will have it??? The stator from the 50 and the 85 and 125 are the same. Check for broken wires and terminals, especially inside the plastic plug-in connectors. We recommend that you remove the pins from the connectors and visually inspect them. Check the flywheel for a broken or loose magnet. Disconnect the kill wires from the CD and connect a DC voltmeter between the kill wires and engine ground, turn the ignition switch on and off several times. If, at any time, you see voltage appearing on the meter, there is a problem in the harness or ignition switch. At NO TIME SHOULD YOU SEE BATTERY VOLTAGE ON A KILL CIRCUIT. Visually inspect stator for burned or discolored areas. If found, replace the stator. If the areas are on the battery charge windings, it indicated a possible problem with the rectifier.

IF NO FIRE ON ANY CYLINDER: Disconnect kill wire AT THE PACK. Check for broken or bare wires on the unit, stator and trigger. Measure DVA voltage of the stator between the output wire sets. With everything connected, readings should be approximately 180 volts or more. Resistance readings between the stator wire sets range from 680 - 800 ohms. Disconnect the rectifier. If the engine fires, replace the rectifier.

NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check stator and trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-5V or more), stator reads 680-800 ohms, DVA 180V or more from blue to yellow. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.

NO FIRE ON TWO CYLINDERS: If two cylinders from the same CD unit will not fire, the problem is usually in the stator. Test per above.

ENGINE WILL NOT KILL: Check kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, possibly the ignition switch.

COILS ONLY FIRE WITH THE SPARK PLUGS OUT: Check for dragging starter or low battery causing slow cranking speed. DVA test stator and trigger.

HIGH SPEED MISS: DVA check stator voltage to each pack at high speed. If it exceeds 400 volts, replace the pack. Disconnect the rectifier. If the engine fires smoothly, replace the rectifier.

Two Cylinder Engines with Combination CD Module with Built-in Ignition Coils (1984-1988)

NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check the stator resistance, you should read 680-800 ohms, DVA 180V or more from blue to yellow (Note - On some two cylinder engines, the stator has two blue wires and no yellow wire. The stator will read from blue to blue). All stator wires should read open to engine ground. Check the trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-5V or more), and open to engine ground. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack

ENGINE WILL NOT KILL: Check kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, or possibly the ignition switch. Disconnect the kill wires from the CD and connect a DC voltmeter between the kill wires and engine ground, turn the ignition switch on and off several times. If, at any time, you see voltage appearing on the meter, there is a problem in the harness or ignition switch. At NO TIME SHOULD YOU SEE BATTERY VOLTAGE ON A KILL CIRCUIT. Check the flywheel for a broken or loose magnet. Check for broken wires and terminals, especially inside the plastic plug-in connectors. We recommend that you remove the pins from the connectors and visually inspect them. Visually inspect stator for burned or discolored areas. If found, replace the stator. If the areas are on the battery charge windings, it indicated a possible problem with the rectifier. IF NO FIRE ON EITHER CYLINDER: Disconnect all kill wires AT THE PACK. Check for broken or bare wires on the unit, stator and trigger. Measure DVA voltage of the stator between the output wire sets. With everything connected, reading s should be approximately 180 volts or more. Resistance readings between the stator wire sets range from 680 - 800 ohms. Disconnect the rectifier. If the engine fires, replace the rectifier. NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check the stator resistance, you should read 680-800 ohms, DVA 180V or more from blue to yellow (Note - On some two cylinder engines, the stator has Iwo blue wires and no yellow wire. The stator will read from blue to blue). All stator wires should read open to engine ground. Check the trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-5V or more), and open to engine ground. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack. ENGINE WILL NOT KILL: Check the kill circuit in the pack by using a juniper wire connected to the white kill wire coming out of the pack and shorting it to ground. If this kills all fire from the pack, the kill circuit in the harness or on the boat is bad, or possibly the ignition switch. COILS ONLY FIRE WITH THE SPARK PLUGS OUT: Check for dragging starter or low battery causing slow cranking speed. DVA test stator and trigger. HIGH SPEED MISS: DVA check stator voltage to each pack at high speed. If it exceeds 400 volts, replace the pack. Disconnect the rectifier. If the engine fires, replace the rectifier. Check for broken wires and terminals, especially inside the plastic plug-in connectors. We recommend that you remove the pins from the connectors and visually inspect them. Check the flywheel for a broken or loose magnet. Disconnect the kill wires from the CD and connect a DC voltmeter between the kill wires and engine ground, turn the ignition switch on and off several times. If, at any time, you see voltage appearing on the meter, there is a problem in the harness or ignition switch. At NO TIME SHOULD YOU SEE BATTERY VOLTAGE ON A KILL CIRCUIT. Visually inspect stator for burned or discolored areas. If found, replace the stator. If the areas are on the battery charge windings, it indicated a possible problem with the rectifier.

 

[diver2diver]

OK so I got the flywheel and stator removed and found a burnt out hole on the the stator. Cleaned down to the coil winding and low and behold I can read OHMS on one wire. So I am now sure this was the issue. Waiting on a new stator and hopefully nothing else is burned out.